Device and method for processing powder and granular material

TECHNICAL FIELD

The present invention relates to a powder grain processing technique used for manufacturing medicines, foods, agricultural chemicals, resins, fertilizers, and the like, and particularly to a technique effectively applicable to a dry granulation apparatus in which powder grains are compacted and formed to manufacture a product.

BACKGROUND ART

As methods for granulating powder grains to manufacture medicines and foods, there are a wet granulation method using wet materials such as water, alcohol or the like, and a dry granulation method in which dried powder grains are compacted and formed by a pair of compression rollers. The dry granulation method obtains stable granules without necessitating wet material and have advantages of shortening of processing time and increasing efficiency of production in order to omit an intermediate step used the wet granulation method. In recent years, frequency in use of the dry granulation method is promoted.

In this dry granulation method, both of the compression rollers receive such a force from supplied powder grains that pushes and opens between the rollers, as a reaction to a compressing force generated during compacting and forming. Therefore, in conventional cases, one of the compression rollers is provided with a hydraulic mechanism to press the other compression roller and, thereby, the other roller is prevented escaping from the one. A dry granulation apparatus of this kind is described, for example, in Japanese Patent Application Laid-Open No. 49-125281 and No. 50-56373. FIGS.

14

(

a

) to

14

(

c

) and

15

are explanatory views showing structures thereof.

Firstly, in the dry granulation apparatus shown in FIG.

14

(

a

), a powder grain container hopper

101

is provided at an upside thereof to temporarily store powder grains

109

that are materials and are transported with air. A feeder

102

that have screw wings for transporting the powder grains

109

supplied from the hopper

101

in a lateral direction is installed at a lower portion of the container hopper

101

. Compression rollers

104

for pressing, with a high pressure, the powder grains

109

fed by the feeder

102

to compress them at a high density are provided below the feeder

102

. In this case, a press cylinder

105

is attached to one of the compression rollers

104

. Further, the one roller

104

is pressed against other roller

104

, so that the other roller

104

is prevented escaping from the one roller

104

during the compacting and forming.

A needle-shearing device

106

for shearing a compacted object that is fed from the rollers

104

is provided below the rollers

104

. Provided below the shearing device

106

is a cutter-shearing device

107

for further shearing granulation sheared by the shearing device

106

to obtain granulation of appropriate shape. A grain refiner

108

for refining the sheared granulation is provided further below the device

107

. Note that these devices are always disassembled into component parts for every lot of products or the like at every appropriate period in order to prevent contamination therein. The parts and process rooms are individually cleaned. In this manner, even with respect to medicinal supplies that should avoid mixture of foreign ingredients, an operation of granulation or the like can be achieved while the devices are consistently kept clean.

Meanwhile, even if the one roller

104

are pressed so as to prevent the other roller escaping from the one roller during the compacting, then powder grains for granulation escape from both end surfaces of the rollers

104

. This results in insufficient compression force and causes a drawback that solid tablets having uniform quality cannot be obtained. To prevent this escape of the powder grains, the granulation apparatus shown in FIG.

14

(

a

) is provided with seal plates

111

and

111

as shown in FIG.

14

(

b

), in a positional relationship as shown in FIG.

14

(

c

). In this case, a pressure-resistant device

113

that is operated by oil pressure or the like is provided on a back part of one of the seal plates

111

. Also, by the pressure-resistant device

113

, the seal plates

111

and

111

are pressed so as not to come apart from end surfaces of the rollers

104

. Accordingly, the powder grains supplied between the rollers

104

and

104

are compacted and formed without escaping and flowing from therebetween.

And, the granulation apparatus shown in FIG.

15

(

a

) is also provided with similar seal plates

125

and

125

. In the granulation apparatus shown in FIG.

15

(

a

), powder grains are supplied from a powder grain container hopper

121

through a screw feeder

122

to a pair of compression rollers

123

and

123

. To prevent the supplied powder grains from escaping between the rollers

123

and

123

during the compacting and forming, seal plates

125

are provided on both end surface sides of the rollers. A hydraulic cylinder

124

is also provided at one of the rollers

123

as described above.

Next, with respect to supply of powder grains to the compression rollers, a screw feeder is used to supply powder grains in many cases as described above. A screw feeder is frequently used in apparatuses, which must feed powder grains, such as a powder packaging apparatus, a powder scale apparatus, and the like, including a granulation apparatus. In this case, there are, in particularly, no problems caused by supply efficiency of the screw feeders in powder grains having a small apparent specific volume. However, there is a drawback that the supply efficiency decreases as the apparent specific volume increases. For example, in a process of performing the compacting and forming by means of compression rollers, the compacting and forming is carried out without problems in case of powder grains having a small apparent specific volume (2.5 and less). On the other hand, if the apparent specific volume is slightly larger (4 to 5), the supply efficiency of the screw feeders decreases. This results in making bad a thrust of the powder grains between the compression rollers, decreasing capacity for compacting and forming the powder grains, and reducing production efficiency. Additionally, if the powder grains have a much larger apparent specific volume (5 and more), the thrust of the powder grains is made worse and, thereby, it is no longer possible to compact and form the powder grains.

Therefore, if the powder grains have a large apparent specific volume, then it is necessary to compress the powder grains twice by the rollers or to compress the powder grains after the powder grains are pre-compressed by another compression device and the apparent specific volume thereof is reduced. That is, this processing has some wasteful steps. Although various methods and apparatuses using a tapered screw, a wave-form roll, a large-diameter roller, or the like have been proposed, any of them cannot be a satisfactory solution. On the other hand, tries for reduction of the apparent specific volume of powder grains have been made. For example, in a fine powder granulation apparatus described in Japanese Patent Application Laid-Open No. 64-44300, a structure is proposed in which fine powder containing much air is subjected to degassing during transportation thereof.

In the apparatus according to the Japanese Patent Application Laid-Open No. 64-44300, as shown in

FIG. 16

, a filter cylinder

132

is provided inside a trough

131

, and screw wings

133

are provided in this filter cylinder

132

. In this case, a ring-like chamber

134

is formed between the trough

131

and the filter cylinder

132

. In addition, the ring-like chamber

134

is connected to a vacuum pump not shown through a communication tube

135

. In this apparatus, the fine powder

137

supplied to a hopper

136

is degassed by the vacuum pump while being fed to the compression rollers

138

by the screw wings

133

. Accordingly, the fine powder

137

comes to have the small apparent specific volume and is supplied between the compression rollers

138

.

Meanwhile, various control methods about a powder grain processing apparatus have been proposed to be able to obtain compacted objects having uniform thickness and hardness without depending on operator's intuition about thickness and hardness.

FIG. 17

is an explanatory view showing a structure of a powder compression apparatus according to Japanese Patent Application Laid-Open No. 51-98682, which is an example of the above-mentioned proposition. In a dry granulating apparatus shown in

FIG. 17

, there are provided a supply hopper

141

, a screw

143

rotated by a motor

142

, and compression rollers

144

and

145

. Powder grains supplied from the hopper

141

are compacted and formed between the rollers

144

and

145

. In this respect, this apparatus is similar to a conventional one.

In this apparatus, however, at the rollers

144

and

145

are provided a thickness detection device

146

for detecting distance between the rollers, and a powder grain supply amount control device

147

. The powder grain supply amount control device

147

controls rotation speed of the motor

142

in correspondence with a detected thickness and adjusts the powder grain supply amount from the hopper

141

. In this case, a device in which a spring supports rotation shafts of the rollers

144

and

145

and which the distance between the rollers is detected on the basis of a pressure caused by the spring or a device in which the distance between the rollers

144

and

145

is detected with using a differential transformer is used as the thickness detection device

146

.

However, the conventional powder grain processing apparatus as described above involves the following problems. At first, in the conventional powder grain processing apparatus, the compression rollers must be pressed by a hydraulic cylinder to increase the compacting and forming effect when compacting the powder grains. And, in order to increase the compacting and forming effect for compressing the powder grains with the rollers, seal plates must be pressed by the hydraulic cylinder. In addition, an actuator for pressing the seal plates or compression rollers, and equipment thereof are required, so that the mechanism of the apparatus is complicated and number of parts thereof is increased. This is a factor causing cost-up. Also, since powder grains attach to the actuator and equipment, contamination of the actuator and equipment may give damage to functions of the apparatus. Hence, it is desired to simplify the mechanism thereof.

Further, there are problems not preferred from view of GMP (Good Manufacturing Practice: manufacturing rules for medicines) for following reasons: products may be polluted by (hydraulic) leakage of fluid from a hydraulic cylinder, a pressure-resistance device, or the like; and abrasion powders that is abraded from the seal plates due to contact between the seal plates and the compression rollers may be mixed in the products. In this case, to prevent the abrasion powders from being generated, a hard seal material requires being used on contact portions between the seal plates and the compression rollers. These result in problems that the price of the seal plates increases and, thereby, the cost for manufacturing the apparatus raises.

In addition, in the conventional apparatus, the hopper, compression rollers and the like are individually detached from the apparatus and then are individually disassembled and cleaned. And, the process rooms are manually cleaned after putting out the apparatus. Therefore, since time and labor are required at cleaning, it is desired to improve the cleaning. In particular, cleaning must be carried out for every one of products that are subjected to batch processing, so that operation of the cleaning is very troublesome and complicated. And, since the cleaning operation tends to be done roughly, severe attention and management are required to achieve the cleaning in compliance with the GMP.

Meanwhile, in the device which detects behaviors of compression rollers to control the powder grain supply amount and to stabilize quality of compression moldings, the behaviors of the compression rollers are detected by a mechanical transmission structure using a spring or the like. Therefore, there is a problem that since dislocation from the reference position is caused due to the physical characteristics of the spring itself, such as hysteresis, settling (permanent set in fatigue), or the like, an accurate detection value cannot be obtained. Also in a device using a differential transformer, an accurate detection value can be no longer obtained due to abrasion of slidable contact points and change of voltage thereof at a transformer. This results in not achieving preferred control.

A first object of the present invention is to provide a powder grain processing apparatus capable of obtaining compression moldings made of powder grains and having uniform thickness and hardness.

A second object of the present invention is to provide a powder grain processing apparatus which has a simple structure without necessitating an actuator pressing the seal plates against the compression rollers and which prevents contamination due to oil leakage or the like and abrasion powders from the seal plates, from being mixed therein.

A third object of the present invention is to provide a powder grain processing apparatus in which a housing of the apparatus is sectioned into a process room and a drive room so that the outside of respective component parts such as a hopper, compression rollers, and the like and the inside of the process room can be automatically cleaned.

A fourth object of the present invention is to provide a powder grain processing apparatus capable of adjusting the compression condition of powder grains that are raw material, without making a complicated operation of exchanging screws.

A fifth object of the present invention is to provide a powder grain processing apparatus capable of controlling hardness of compression moldings by recognizing condition of the compression moldings as numerical values on manufacturing lines thereof.

The above-described and other objects and novel features of the present invention will be apparently understood from description of the present specification and the drawings appended hitherto.

DISCLOSURE OF THE INVENTION

Representative aspects of the present invention disclosed in the present application will be briefly summarized as follows.

An apparatus for processing powder grains according to the present invention, having a pair of compression rollers arranged in parallel with each other and supplying powder grains to a powder grain introduction/compression part formed between the compression rollers, thereby forming compressing moldings of the powder grains, includes a seal members being provided to face side surfaces of the compression rollers with clearance maintained from the compression rollers, and forms closer layers of the powder grains between the seal members and side surfaces of the compression rollers when the powder grains enter into the clearance, thereby sealing the powder grain introduction/compression part.

Another apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and supplying powder grains between the compression rollers, thereby forming compression moldings of the powder grains, comprises; a pressure detection means for detecting a pressure which the powder grains receive when the powder grains are pressed between the compression rollers; and a control means for adjusting hardness of the powder grains fed from the compression rollers in accordance with the pressure detected by the detection means.

Still another apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and supplying powder grains between the compression rollers, thereby forming compression moldings of the powder grains, comprises; a fine change amount detection means for detecting a fine change of a distance between the compression rollers, the fine change being caused by a pressure which the powder grains receive when the powder grains are pressed between the compression rollers; and a control means for adjusting hardness of the powder grains fed from the compression rollers in accordance with a fine change amount of the distance between the compression rollers, the fine change amount being detected by the fine change amount detection means.

In an apparatus for processing powder grains according to the present invention, the control means may adjust a pressure applied to the powder grains.

An apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and supplying powder grains between the compression rollers, thereby forming compressing moldings of the powder grains, comprises; a pair of compression roller support shafts for supporting the compression rollers; a compression roller support part for holding the compression roller support shafts; a distortion detection means attached to the compression roller support part and measuring distortion caused at the compression roller support part by a pressure which the compression rollers receive when the powder grains are pressed between the compression rollers; and a control means for adjusting the pressure applied to the powder grains in accordance with a distortion value caused at the compression roller support part, the distortion value being obtained by the distortion detection means.

In an apparatus for processing powder grains according to the present invention, the powder grain processing apparatus further comprises a powder grain press/feed means for feeding the powder grains to the compression rollers, and the control means may control the powder grain press/feed means, thereby adjusting a feed amount of the powder grains. And, the control means may control a rotation speed of the compression roller.

An apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and supplying powder grains between the compression rollers, thereby forming compression moldings thereof, comprises; a pitcher hopper provided in a front stage of the compression rollers and storing the powder grains supplied to the compression rollers; and a powder grain press/feed means connected to the pitcher hopper, arranged between the pitcher hopper and the compression rollers, and pressing and feeding the powder grains to the compression rollers, wherein the powder grain press/feed means has a transport tube internally including a screw member for pressing and feeding the powder grains.

In an apparatus for processing powder grains according to the present invention, the transport tube may comprise a deaerating barrel and a deaerating jacket, the deaerating barrel containing the screw member and being made of a member which allows air to pass and does not allow the powder grains to pass, and the deaerating jacket covering the deaerating barrel and being provided with a deaerating vent at a part thereof.

In an apparatus for processing powder grains according to the present invention, the deaerating barrel may be made of porous metal material. And, the hopper may be provided to be movable relatively along the screw member. Moreover, the hopper and the transport tube may be provided to be movable relatively along the screw member. In addition, the screw member may be provided to be able to change a distance between the screw member and the compression rollers.

An apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and supplying powder grains between the compression rollers, thereby forming compression moldings of the powder grains, comprises; a powder grain processing room sealing hermetically and containing the compression rollers in a watertight condition; and a cleaning means provided in the powder grain processing room and injecting a cleaning liquid into the powder grain processing room.

In an apparatus for processing powder grains according to the present invention, the cleaning means may be provided at least one of an upper part and side parts of the powder grain processing room.

An apparatus for processing powder grains according to the present invention, having a pair of compression rollers parallel with each other and a powder grain press/feed means for supplying powder grains to the compression rollers, and supplying the powder grains between the compression rollers with use of the powder grain press/feed means, thereby forming compression moldings of the powder grains, comprises; a shearing means provided in a rear stage of the compression rollers and shearing the compression moldings formed by the compression rollers; and a load detection means for detecting a load applied to the shearing means.

In an apparatus for processing powder grains according to the present invention, the apparatus may further comprise a control means for controlling at least one of the powder grain press/feed means and the compression rollers in accordance with data detected by the load detection means. And, the load detection means may detect rotation torque of the shearing means.

Further, the powder grain processing apparatus may be a roller compactor by dry granulating apparatus.

A method for processing powder grains according to the present invention, having a step of supplying powder grains between a pair of compression rollers arranged in parallel with each other, with use of a powder grain press/feed means provided in a front stage of the compression rollers, thereby forming compression moldings of the powder grains, comprises; a step of detecting a load applied to a shearing means during shearing the compression moldings formed by the compression rollers by means of the shearing means provided in a rear stage of the compression rollers; and a step of controlling at least one of the powder grain press/feed means and the compression rollers in accordance with the load detected.

In a method for processing powder grains according to the present invention, the load may be rotation torque for driving the shearing means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.

1

(

a

) is an explanatory view showing a structure of a dry granulating apparatus which is embodiment 1 of the present invention, and is a front view thereof.

FIG.

1

(

b

) is an explanatory view showing a structure of a dry granulating apparatus which is embodiment 1 of the present invention, and is a side view thereof.

FIG.

2

(

a

) is an explanatory view showing a structure of a powder grain processing room in the dry granulating apparatus shown in FIG.

1

(

a

), and is a front view thereof.

FIG.

2

(

b

) is an explanatory view showing a structure of a powder grain processing room in the dry granulating apparatus shown in FIG.

1

(

b

), and is a side view thereof.

FIG. 3

is a plane view of the dry granulating apparatus shown in FIG.

1

(

a

).

FIG. 4

is an explanatory view showing a structure of the powder grain transport means in the dry granulating apparatus shown in FIG.

1

(

a

).

FIG.

4

(

a

) is an explanatory view showing one embodiment of an introduction/compression part shown in

FIG. 4

in a greater detail and is an exploded perspective view thereof.

FIG.

5

(

a

) is an explanatory view showing a structure of a closer member, and is a plane view thereof.

FIG.

5

(

b

) is an explanatory view showing a structure of a closer member, and is a front view thereof.

FIG.

5

(

c

) is an explanatory view showing a structure of a closer member, and is a base view thereof.

FIG. 6

is an explanatory view showing a structure of a compression roller mechanism.

FIG. 7

is an explanatory view showing a structure of side seals.

FIGS.

8

(

a

) and

8

(

b

) are explanatory views showing a structure of a shearing device, FIG.

8

(

a

) is a plan view thereof, and FIG.

8

(

b

) is a front view thereof.

FIG. 9

is a block diagram showing a structure of a control circuit associated with the shearing device.

FIG. 10

is an explanatory view showing a structure of an elevation device.

FIG.

11

(

a

) is an explanatory view showing a structure of a dry granulating apparatus which is embodiment 2 of the present invention, and is a front view thereof.

FIG.

11

(

b

) is an explanatory view showing a structure of a dry granulating apparatus which is embodiment 2 of the present invention, and is a side view thereof.

FIG.

12

(

a

) is an explanatory view showing a structure of a powder grain processing room in the dry granulating apparatus shown in FIG.

11

(

a

), and is a front view thereof.

FIG.

12

(

b

) is an explanatory view showing a structure of a powder grain processing room in the dry granulating apparatus shown in FIG.

11

(

b

), and is a side view thereof.

FIG. 13

is a plane view of the dry granulating apparatus shown in FIG.

9

.

FIG.

14

(

a

) is an explanatory view showing a structure of a conventional powder grain processing apparatus, and shows the entire structure thereof.

FIG.

14

(

b

) is an explanatory view showing a structure of a conventional powder grain processing apparatus, and shows the structure of a seal plates and a metal plate used in the granulation apparatus shown in FIG.

14

(

a

).

FIG.

14

(

c

) is an explanatory view showing a structure of a conventional powder grain processing apparatus, and shows the relationship between the seal plates and the compression rollers.

FIG. 15

is an explanatory view showing a structure of another conventional processing apparatus.

FIG. 16

is an explanatory view showing a structure of another conventional processing apparatus.

FIG. 17

is an explanatory view showing a structure of another conventional processing apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be explained below in details on the basis of the drawings.

(Embodiment 1)

FIGS.

1

(

a

) and

1

(

b

) are explanatory views showing a structure of a dry granulating apparatus (a powder grain processing apparatus) which is embodiment 1 of the present invention. FIG.

1

(

a

) is a front view thereof and FIG.

1

(

b

) is a side view thereof. And, FIGS.

2

(

a

) and

2

(

b

) are explanatory views showing a structure inside a powder grain processing room of the dry granulating apparatus shown in FIGS.

1

. FIG.

2

(

a

) is a front view thereof and FIG.

2

(

b

) is a side view thereof. Further,

FIG. 3

is a plan view of the dry granulating apparatus shown in FIG.

1

.

As shown in

FIG. 1

, said dry granulating apparatus has a housing

1

set on a floor surface G. The housing

1

is divided, by a partition wall

2

, into a powder grain processing room

70

where processing of powder grains is actually carried out, and a drive room

4

where a control operation panel, a motor, and the like are arranged.

In the processing room

70

, the powder grains are supplied from a supply hopper

8

provided on an upper portion of the housing

1

. The powder grains are fed from a powder grain storage vessel

5

through a hose

71

by vacuum transportation, for example, using an ejector. A powder grain transport means

17

and a compression roller mechanism

18

are provided in the processing room

70

. The transport means

17

has a pitcher hopper

19

for receiving and storing the supplied powder grains, and a powder grain press/feed means

20

vertically connected to a lower portion of the hopper

19

.

The press/feed means

20

comprises a screw (screw member)

23

and a transport tube

69

. The screw

23

is linked through a decelerator

22

to a drive shaft of a motor

21

provided with the top portion of the housing

1

. The transport tube

69

comprises a deaerating barrel

24

, a deaerating jacket

25

covering outside of the deaerating barrel

24

, and a deaerating vent

26

connected to a not shown vacuum suction means provided on the jacket

25

. The transport tube

69

need not always be structured to have a deaerating function as described above.

As shown in

FIG. 4

, the hopper

19

is a container having a funnel-like shape with handles

27

equipped on an outer circumferential surface thereof. The screw

23

is vertically inserted in the hopper

19

along center axis thereof. Inside the hopper

19

, a scraper

28

attached to the screw

23

is provided to be rotatable and slidable along an inner circumferential surface

19

a

of the funnel-like shape of the hopper

19

. A short tube part

29

is formed on a lower end of a diminishing diameter direction of the hopper

19

. A joint flange

29

a

is provided on an outer circumference of the short tube part

29

. A brim part

31

fitting in a ring-like packing

30

is welded to an upper surface of the hopper

19

.

The deaerating barrel

24

having the same diameter as that of the short tube part

29

is jointed at the lower portion of the short tube part

29

. This barrel

24

is made of a member which allows air to pass but does not allows powder grains to pass, for example, porous material such as sintered metal, ceramics, or the like. In addition, a flange part

24

a

is formed on the outer circumference of the barrel

24

. Although

FIG. 4

shows a structure in which both end surfaces of the short tube part

29

and the barrel

24

are joined to each other, these end surfaces may be coupled by a socket-and-spigot joint to improve adhesion of both end surfaces.

Joint flanges

32

and

33

are welded to upper and lower parts of the deaerating jacket

25

, respectively. The joint flange

29

a

of the short tube part

29

is joined to the upper flange

32

so as to put the flange

24

a

between the flange

24

a

of the barrel

24

and the joint flange

29

a.

The flange

32

and the flange

29

a

are fixed by a clamp

34

. In this manner, the jacket

25

is fixed integrally and coaxially to a lower part of the hopper

19

so as to contain the barrel

24

a

therein. At this time, such a jacket structure is formed that the jacket

25

is separated by a desirable space from the barrel

24

and covers outside of the barrel

24

. So, a deaerating room

35

is formed between the jacket

25

and the barrel

24

. And, the deaerating vent

26

is provided so as to communicate with the deaerating chamber

35

and is connected to a vacuum pump not shown.

The flange

33

at a lower part of the jacket

25

is formed in a quadrangular shape, and a closer member

36

is joined to a lower part of the flange

33

. A through hole

33

a

for tightening a long screw is formed in the flange

33

, and the closer member

36

and the compression roller mechanism

18

are joined to each other by tightening the long screw not shown into the through hole

33

a.

FIGS.

5

(

a

) to

5

(

c

) are explanatory views showing a structure of the closer member

36

. FIG.

5

(

a

) is a plan view thereof, FIG.

5

(

b

) is a front view thereof, and FIG.

5

(

c

) is a base view thereof. As shown in FIG.

5

(

a

), the closer member

36

is formed in a quadrangular shape. A convex part

36

a

inserted and joined into the flange

33

of the jacket

25

is integrally formed with a through hole

36

b

having the same diameter as that of the barrel

24

. Provided in the lower surface thereof are a dovetail groove

36

c

formed such that a side seal (a seal member)

37

attached to the compression roller mechanism

18

described hereinafter can be inserted, and a clearance parts

36

d

for avoiding interference with the compression rollers

38

a

and

38

b.

Further, through holes

36

e

for tightening long screws inserted into the jacket

25

are provided in the closer member

36

, and moreover handles

36

f

are fixed at both sides thereof.

Next, the compression roller mechanism

18

is fixed to the not shown lower surface of the closer member

36

by the not shown long screws which are inserted into the through holes

33

a

and

36

e

described above.

FIG. 6

is an explanatory view showing a structure of the roller mechanism

18

. The roller mechanism

18

has a pair of compression rollers

38

a

and

38

b

key-connected to compression roller support shafts

39

a

and

39

b.

And, the powder grains supplied from the powder grain transport means

17

are pressed by these rollers

38

a

and

38

b.

In the roller mechanism

18

, a front frame block (hereinafter abbreviated as a frame)

41

and a rear frame block (hereinafter abbreviated as a frame)

42

are provided. Screw holes

40

, which are formed so as to correspond to the through holes

33

a

and

36

e

and to tighten long screws therein, are provided in the frame

41

. The frames

41

and

42

are arranged in parallel with a movable wall

46

attached to the partition wall

2

. The rollers

38

a

and

38

b

are arranged between the frames

41

and

42

so as to be engaged with each other. Bearings

43

a

to

43

d

are attached to the frames

41

and

42

by bearing stoppers

44

a

to

44

d.

The compression roller support shafts

39

a

and

39

b

are supported on these bearings

43

a

to

43

d.

And, compression roller support parts for holding the shafts

39

a

and

39

b

are formed by the frames

41

and

42

, the bearings

43

a

to

43

d,

and the bearing stoppers

44

a

to

44

d.

Further, a tie-rod

45

is provided between the frames

41

and

42

to maintain a distance between frame blocks.

Constant velocity gears

47

a

and

47

b

are attached, respectively, to the pair of shafts

39

a

and

39

b.

The shaft

39

b

is connected to a compression roller drive motor

48

through a coupling

49

. Therefore, as the motor

48

is rotated, the roller

38

b

rotates clockwise and the roller

38

a

rotates counterclockwise at constant velocity.

Meanwhile, as shown in

FIG. 4

, a powder grain introduction/compression part

50

is provided between the rollers

38

a

and

38

b.

In this introduction/compression part

50

, the powder grains are supplied from the powder grain transport means

17

. Also, as these rollers are rotated, the supplied powder grains are pressed between the rollers

38

a

and

38

b.

In the roller mechanism

18

according to the present invention, as shown in

FIG. 4

, side seals

37

of

FIG. 7

are provided on both side surfaces of the rollers

38

a

and

38

b

in order to cover the introduction/compression part

50

.

FIG. 7

is explanatory view showing a structure of one of these side seals

37

. That is, the present apparatus is structured so that the powder grains are prevented from leaking out from the rollers

38

a

and

38

b

by means of providing the side seals

37

between rollers

38

a

and

38

b

and frames

41

and

42

, respectively.

Each of the side seals

37

is made of Teflon material as shown in

FIG. 7

, for example. In an upper portion of respective side seals, a convex part

37

a,

which is slidably engaged with the dovetail groove

36

c

of the closer member

36

, is formed. A lower portion of each of the side seals

37

has such a tapered part

37

b

as to correspond to the shape of the introduction/compression part

50

. The side seals

37

are inserted between the frame

41

and the roller

38

a

and

38

b,

and between the frame

42

and the roller

38

a

and

38

b,

respectively, so as to have a clearance

72

of about 0.1 to 0.3 mm. In this manner, since the powder grains enter between side seals

37

and each side surface of the rollers

38

a

and

38

b

and a closer layer is formed by the powder grains, the powder grain introduction/compression part

50

is sealed by the layer. FIG.

4

(

a

) shows in greater detail one embodiment of the introduction/compression part

50

.

FIG. 6

shows the clearance

72

emphasized in size, in order to understand easily a relationship between side seals

37

and each of the rollers

38

a

and

38

b.

Thus, according to the present invention, a closer layer is made of only the powder grains by using the side seals

37

, and the introduction/compression part

50

is sealed thereby. Therefore, it is unnecessary to use an actuator or the like such as a hydraulic cylinder for pushing the seal plates, the actuator being used in the conventional powder grain processing apparatus. So, the distance between the frames

41

and

42

can be shorter than that of the conventional apparatus. Accordingly, the shafts

39

a

and

39

b

can be shortened so that rigidity of the roller mechanism

18

itself can be improved.

Also, the introduction/compression part

50

is surrounded by the side seals

37

, the pair of rollers

38

a

and

38

b,

and the lower surface of the closer member

36

. By this manner, it is possible to obtain a rigid structure capable of withstanding a pressure that is caused when the powder grains pressed and fed by the press/feed means

20

, are fed between the rollers

38

a

and

38

b.

Meanwhile, in the conventional powder grain processing apparatus, one of the rollers

38

a

and

38

b

is pushed by the hydraulic cylinder or the like, in order to prevent such a force from being reduced that the rollers

38

a

and

38

b

press powder grains due to repulsion between the powder grains and the rollers

38

a

and

38

b.

In contrast, in the present dry granulating apparatus, the rollers

38

a

and

38

b

are fixed and the constant distance is maintained between the axes thereof without using an actuator such as a hydraulic cylinder or the like. In the structure like this, the roller mechanism

18

is greatly simplified and contaminations caused by a hydraulic device or the like can be much more prevented, in comparison with the conventional apparatuses. On the other hand, this structure has a risk that the rollers

38

a

and

38

b

may move apart from each other and that a sufficient compression force cannot be obtained at the time of pressing the powder grains if no countermeasure is taken. That is, when the powder grains are supplied to the powder grain introduction/compression part

50

and pressed between the rollers

38

a

and

38

b,

repulsion against a compression force for pressing the powder grains is generated in the rollers

38

a

and

38

b.

Therefore, since each of the rollers

38

a

and

38

b

receives the force in opposite direction of each other, a larger clearance than needed is caused between the rollers and the compression force for pressing the powder grains is reduced.

Hence, in the dry granulating apparatus, a sensor (a distortion detection means)

51

for detecting metal distortion (strain) is adhered to the frame

42

, so that the conditions of the rollers

38

a

and

38

b

can be detected in details. That is, if being applied to the rollers

38

a

and

38

b

from the powder grains, repulsion is transmitted to the frames

41

and

42

through the roller support shafts

39

a

and

39

b

as well as the bearings

43

a

to

43

d.

The frame

42

is then distorted by this force. In this case, the distortion of the frame

42

corresponds to the repulsion applied from the powder grains to the rollers

38

a

and

38

b

in the introduction/compression part

50

. Accordingly, it is possible to know strength of the force compressing the powder grains by measuring the distortion. And, it is possible to maintain constantly optimal processing conditions by changing operation conditions of the apparatus as based on measured values. That is, if being decreased, the compression force can be recovered by lowering operation speed of the press/feed means

20

to reduce supply amounts of the powder grains or by reducing the rotation speed of the rollers

38

a

and

38

b

or by other methods.

In this case, a metal distortion sensor of an adhesion type that is commercially available is normally used as the sensor

51

. This metal distortion sensor is constructed by foil made of copper alloy such as nickel-copper, copper-constantan, or the like and detects a distortion change as a change of a resistance value. As shown in

FIG. 6

, in the present dry granulating apparatus, the sensor

51

is connected to a distortion detector

52

and to, for example, a pressure gage

54

as an indicator and a control device

55

through a direct current amplifier

53

from the distortion detector

52

. In this manner, when the powder grains are fed from the rollers

38

a

and

38

b,

pressure that the rollers

38

a

and

38

b

receive is detected. If the pressure is decreased, the operation conditions for driving the press/feed means

20

and the rollers

38

a

and

38

b

are automatically controlled by the control device

55

, so that the compression force is adjusted to a predetermined value. Note that this value being output may be used as an alarm buzzer. And, reduction of the pressure force or a withstand pressure limit value may be informed to an operator, so that the operator can manually control the operation conditions.

Meanwhile, a shearing device (shearing means)

75

is provided below the compression roller mechanism

18

, as shown in FIG.

2

. This shearing device

75

shears sheet-like or flake-like compression moldings W pressed by the roller mechanism

18

, and measures hardness of the compression moldings W by a torque sensor described later. FIGS.

8

(

a

) and

8

(

b

) are explanatory views shown a structure of this shearing device

75

. FIG.

8

(

a

) is a plan view thereof, and FIG.

8

(

b

) is a front view thereof.

The shearing device

75

comprises a shearing member

76

for shearing compression moldings W squeezed out from the rollers

38

a

and

38

b,

a shearing member drive motor

77

(hereinafter abbreviated as a motor

77

) used as a rotation drive source for rotating the shearing member

76

, and a torque sensor (a load detection means)

78

for measuring a load when the shearing member

76

is rotated. In this case, the shearing member

76

is formed in a tuning-folk-like shape having two arms

76

a,

and is located and installed below the introduction/compression part

50

of the rollers

38

a

and

38

b.

And, the arms

76

a

are rotated by the motor

77

, thereby shearing and smashing the compression moldings W squeezed out from the rollers

38

a

and

38

b.

The motor

77

is provided on a slider

60

of an elevation mechanism

56

described below adjacent to the motor

48

. And, a sensor shaft

81

of the torque sensor

78

is rotated through a belt

80

driven by the drive shaft

77

a

of the motor

77

. The sensor shaft

81

of the sensor

78

links the shearing member

76

and the motor

77

to each other. And, load caused by rotation of the shearing member

76

, is converted into an electric signal and then is output. The shearing member

76

and the sensor

78

are supported by bearings

79

a

and

79

b

mounted on a motor base

57

of the elevation mechanism

56

. For the structure like this, the sensor

78

can exactly measure fragility of the compression moldings W without affected by the shearing operation of the shearing member

76

.

A commercially available sensor is used as the torque sensor

78

. When a torque is applied to the sensor shaft

81

, the sensor

78

outputs a voltage proportional to the torque.

FIG. 9

is a block diagram showing a structure of a control circuit associated with the shearing device

75

. As shown in

FIG. 9

, a detection value obtained from the sensor

78

is output to a control part (control means)

91

comprising a microcomputer

89

and servo amplifiers

90

a

to

90

c.

And, rotation control signals are output from the control part

91

to the motor

21

of the press/feed means

20

or the motor

48

of the rollers

38

a

and

38

b.

The control part

91

has the microcomputer

89

which processes the rotation control signals for indicating the rotation speed of the motors

21

and

48

on the basis of the voltage being output from the sensor

78

. The control part

91

also has servo amplifiers

90

a

and

90

b

for driving motors

21

and

48

, respectively, on the basis of the rotation control signals formed by and output from the microcomputer

89

, and signals from tachometer generator

93

a

and

93

b.

And, the control part

91

controls rotation of the rollers

38

a

and

38

b

and the press/feed means

20

by the microcomputer

89

and servo amplifiers

90

a

and

90

b,

respectively. That is, if the torque for rotating the shearing member

76

is increased, it is determined that the compression moldings W become hard (a high density). In accordance with this determination, the rotation speeds of the rollers

38

a

and

38

b

and the press/feed means

20

are controlled to lower density of the compression moldings W. On the other hand, if the torque is decreased, it is determined that the compression moldings become low density, and then the rotation speeds of the rollers

38

a

and

38

b

and the press/feed means

20

are controlled. Note that condition of the compression moldings W may be controlled by either the rollers

38

a

and

38

b

or the press/feed means

20

, or by both.

Thus, in the present dry granulating apparatus, the sensor

78

of the shearing device

75

can detect hardness, fragility, and the like of the compression moldings W at any time, and control the press/feed means

20

and the rollers

38

a

and

38

b

on the basis of the detected data. In addition, the shearing member

76

can also be driven in compliance with the squeezing speed of the compression moldings W, so that the shearing device

75

can be driven under an optimal condition which complies with the fragility or the like of the compression moldings W. By this way, the compression moldings W can be obtained which become uniform in the fragility or the like, so that it is possible to achieve stabilized quality of granular productions by whole graining them.

The compression roller drive motor

48

is mounted on the motor base

57

provided in the processing room

70

such that the base

57

can freely move up and down.

FIG. 10

is an explanatory view showing a structure of the elevation mechanism

56

. The base

57

is fixed to the movable wall

46

, as shown in FIG.

2

(

b

). Also, the compression roller mechanism

18

, integrally connected to the hopper

19

, the jacket

25

, and the closer member

36

, is fixed at the movable wall

46

. Accordingly, the roller mechanism

18

and the like are integrally moved up and down in the processing room

70

as the base

57

moves up and down.

The elevation mechanism

56

, moving the base

57

up and down, comprises guides

58

and

58

fixed at both inner side surfaces of the housing

1

, a hydraulic cylinder

59

, and the slider

60

moved up and down along the guide

58

by the cylinder

59

, as shown in FIG.

10

. Therefore, as the cylinder

59

is operated, the base

57

moves up and down so that the roller mechanism

18

and the hopper

19

, set on the movable wall

46

, move up and down in the processing room

70

. FIG.

2

(

b

) shows an elevation state of the hopper

19

, and the hopper

19

can move between positions indicated by both solid line and one chain line.

In the present dry granulating apparatus, a distance between one end part of the screw

23

and the rollers

38

a

and

38

b

can be appropriately changed by the elevation mechanism

56

. Accordingly, for example, in case of powder grains which cohere for the feed force caused by rotation of the screw

23

in the presence of the rollers

38

a

and

38

b,

the distance is set to enlarge, so that the cohesion is prevented beforehand. Conventionally, a length of the screw

23

is changed to prevent the cohesion. Therefore, by preparing various screws having different lengths, such screws are properly exchanged in accordance with kinds of powder grains, respectively. However, in the dry granulating apparatus according to the present invention, only one screw can be widely applied to various kinds of powder grains because the screw

23

is fixed at the movable hopper

19

. Accordingly, replacement services and kinds of screw can be reduced.

In addition, positional relationship between the screw

23

and the hopper

19

can be appropriately changed as shown in FIG.

2

(

b

), since the screw

23

in the press/feed means

20

is fixed at the housing

1

. That is, a length of the screw

23

entering into the barrel

24

can be appropriately adjusted, so that the press/feed means

20

can change a distance feeding the powder grains. Accordingly, compressing condition of the screw

23

can be appropriately changed depending on kinds of powder grains. In this case, it is also unnecessary to prepare various kinds of screw

23

in accordance with the kinds of powder grains.

Further, a cleaning device (a cleaning means)

73

for cleaning inside of the processing room

70

, the hopper

19

, and the roller mechanism

18

is provided in the processing room

70

. The cleaning device

73

comprises cleaning nozzles

61

and cleaning nozzles

62

. The cleaning nozzles

61

are provided on the inner circumferential surface of the hopper

19

with an appropriate distance maintained therefrom and inject a cleaning liquid to the inner surface of the hopper

19

. And the cleaning nozzles

62

are arrested at an appropriate portion of the inner wall surface of the processing room

70

, respectively. The nozzles

62

are attached to cleaning tubes

63

provided and extended vertically in the processing room

70

. The cleaning tubes

63

and the nozzles

61

are connected to a cleaning liquid supply pump not shown. In addition, a drain tube

64

for draining the cleaning liquid after finishing the cleaning is provided on a bottom surface of the processing room

70

.

The inside of the processing room

70

is watertight so that the cleaning liquid might not leak to the outside thereof during cleaning. Therefore, a seal member

65

is adhered to an edge of an opening portion

2

a

formed in the partition wall

2

in order to connect the roller mechanism

18

with the motor

48

. And, the processing room

70

and the drive room

4

maintain a sealed watertight condition by installing the movable wall

46

which moves slidably on the seal

65

with watertight contact maintained therebetween.

A door

66

which can be opened and closed with respect to the housing

1

is provided at a front surface part of the processing room

70

. Also, a transparent window

67

is fitted in the door

66

so that the inside of the processing room

70

can be observed from the outside. Further, vibration isolation bases

68

are provided between the housing

1

and the floor surface G, thereby supporting the dry granulating apparatus while preventing vibrations.

Next explanation will be made of granulation operation in the dry granulating apparatus having the structure as described above. At first, in the present dry granulating apparatus, raw powder grains are vacuum-transported from the storage vessel

5

through a hose

71

to the hopper

8

. The powder grains supplied to the hopper

8

have a high specific volume and a high bulk density. The powder grains supplied to the hopper

8

are thrown into the hopper

19

.

When the hopper

19

is at a moved-up position thereof, the packing

30

of the top part thereof has a tight contact with a back surface of a top board of the housing

1

. Supply of powder grains into the hopper

19

is carried out by a down move of the hopper

19

. Then, the hopper

19

is moved up, and the inside of the hopper

19

is kept on closed condition. Accordingly, the powder grains supplied into the hopper

19

are stored in the hopper

19

without scattering or leaking to the outside of the hopper

19

. The top part of the hopper

19

is provided so as to be able to move up and down from a position of abutting on a back surface of the housing

1

, to a position down from the position due to the elevation mechanism

56

. Therefore, it is possible to throw manually different kinds of powder grains in a clearance gap opened in the upper part of the hopper

19

by moving down the hopper

19

.

Next, the powder grains in the hopper

19

are fed to the roller mechanism

18

through the transport means

17

. That is, the powder grains are fed downward from the hopper

19

by the screw

23

of the press/feed means

20

. At this time, since the scraper

28

is rotated in accordance with rotation of the screw

23

, the powder grains in the hopper

19

are transported into the transport tube

69

by both self-weight of the powder grains and rotation of the screw

23

.

Since the transport tube

69

communicates with the short tube part

29

of the hopper

19

, the powder grains are supplied into the barrel

24

of the short tube part

29

through the short tube part

29

. In this case, the barrel

24

is made of a permeable member and the jacket

25

connected to a vacuum pump not shown is provided around the barrel. In addition, the closer member

36

and the roller mechanism

18

are provided under the jacket

25

. Accordingly, the powder grains in the barrel

24

pressed and fed under a negative pressure by the screw

23

in such a state that flow of the powder grains is temporarily stored and squeezed by the closer member

36

and the roller mechanism

18

. Therefore, the powder grains are pressed in the barrel

24

and then air included in the barrel

24

is deaerated outward. And, the air, included in the powder grains, passes from micro holes of the barrel

24

through the deaerating room

35

to the deaerating port

26

of the jacket

25

and is forced to vacuum-suck from the deaerating port

26

.

The powder grains pressed and fed by the press/feed means

20

are supplied to the introduction/compression part

50

formed between the rollers

38

a

and

38

b.

Since the rollers

38

a

and

38

b

rotate in the inward direction so as to be engaged with each other, the powder grains are put therebetween, fed out, and pressed at a high density. At this time, the side seals

37

of the roller mechanism

18

are slightly slid in the dovetail groove

36

c

of the closer member

36

due to the compression force of the powder grains, the compressing force being caused by the press/feed means

20

. So, the clearance

72

of about 0.1 to 0.3 mm is formed between both side surfaces of the rollers

38

a

and

38

b

and the side seals

37

. Further, the powder grains enter into the clearance

72

of about 0.1 to 0.3 mm thereby forming cross-bridges between both side surfaces of the rollers

38

a

and

38

b

and the side seals

37

. In this manner, it is possible to prevent the powder grains from leaking to the outside from the rollers

38

a

and

38

b.

Also, since the rollers

38

a

and

38

b

do not contact the side seals

37

, abrasion powders of the side seals

37

or the rollers

38

a

and

38

b

is not mixed into the powder grains. Further, heat is not generated by friction between the rollers

38

a

and

38

b

and the side seals

37

, and the product quality can be stabilized.

In addition, when the rollers

38

a

and

38

b

receive the repulsion due to the compression force to the powder grains, the repulsion is transmitted to the frames

41

and

42

through the shafts

39

a

and

39

b

and the bearings

43

a

to

43

d.

The frame

42

is distorted by this repulsion. In the present dry granulating apparatus, the sensor

51

is adhered to the frame

42

to detect condition of the rollers

38

a

and

38

b

when the powder grains are pressed. That is, the distortion of the frame

42

changes the resistance balance of the sensor

51

, and this change is detected as a voltage difference by the distortion detector

52

. And, this voltage difference is transmitted to the pressure gage

54

and the control device

55

through the direct current amplifier

53

. Accordingly, the granulate-grain-size distribution of flake-like compression moldings fed from the rollers

38

a

and

38

b

can be determined by visually monitoring the numerical value of this pressure gage

54

. In addition, data obtained by A/D-converting the detected voltage difference, is supplied to the control device

55

, and each rotation speed of the motors

21

and

48

is controlled on the basis of the data, and then it is possible to obtain compression moldings having the preferable granulate-grain-size distribution.

The compression moldings W fed from the rollers

38

a

and

38

b

are sheared by the shearing member

76

provided under the shearing device

75

. In this case, the rotation torque of the shearing member

76

is detected by the sensor

78

, and the control part

91

controls the rotation speeds of the motors

21

and

48

on the basis of the detection data. Accordingly, the condition of the compression moldings W can be grasped on real time in the present dry granulating apparatus. And, the rotations of the press/feed means

20

and the rollers

38

a

and

38

b

are controlled so that the compression moldings having optimal hardness and fragility can be obtained constantly. Note that, after the powder grains are sheared by the shearing device

75

, the sheared powder grains are supplied to the grain refiner not shown and then granulate products are obtained.

Meanwhile, the processing room

70

is cleaned by the cleaning device

73

after the steps of granulating desired granular products are completed. In this case, in the present dry granulating apparatus, the hopper

19

is firstly moved up by the elevation mechanism

19

and is cleaned in a state where its top part is kept in contact with the back surface of the housing

1

. At this time, the processing room

70

is kept sealed. In this condition, the inner surface of the hopper

19

, the barrel

24

, the closer member

36

, the side seals

37

of the roller mechanism

18

, and the rollers

38

a

and

38

b

of the roller mechanism

18

are cleaned by the nozzle

61

. Next, the hopper

19

, the jacket

25

, the closer member

36

, and the roller mechanism

18

are moved down by the elevation mechanism

56

. These components are cleaned from the outside thereof by the nozzle

62

and the inside of the processing room

70

is cleaned. Thus, in the dry granulating apparatus according to the present invention, the respective component parts need not be disassembled for cleaning, unlike the conventional apparatuses. Therefore, the number of steps required for disassembling and cleaning this apparatus can be greatly reduced.

The barrel

24

and the jacket

25

can be appropriately replaced with other ones that have a different length size, a different pore roughness, and the like depending on the kind of powder grains. And, the service for replacing the barrel

24

and the jacket

25

is carried out as follows; That is, the hopper

19

is firstly moved down by the elevation mechanism

56

to detach the screw

23

from the barrel

24

. Next, the clamp

34

coupling the flange

29

a

of the short tube part

29

and the flange

32

of the barrel

24

with each other is removed. In addition, the long screws screwed into the frames

41

and

42

through the through holes

33

a

in the flange

33

is loosened and pulled off from the through holes

33

a,

respectively. In this state, the jacket

25

together with the barrel

24

is pulled out. Further, a barrel and a jacket that have different specifications are set under the flange

29

a

and are installed between the hopper

19

and the closer member

36

with use of the long screws and the clamp

34

. Thereafter, the long screws are screwed into the frames

41

and

42

and fixed thereto, respectively, and the service for replacing the barrel

24

and the jacket

25

with each other is thus completed.

(Embodiment 2)

Explanation will further be made of a dry granulating apparatus which is the second embodiment of the present invention. FIGS.

11

(

a

) and

11

(

b

) are explanatory views showing a structure of the dry granulating apparatus (a powder grain processing apparatus) according to the present embodiment. FIG.

11

(

a

) is a front view thereof and FIG.

11

(

b

) is a side view thereof. FIGS.

12

(

a

) and

12

(

b

) are explanatory views showing a structure in a powder grain processing room of the dry granulating apparatus shown in FIGS.

11

(

a

) and

11

(

b

). FIG.

12

(

a

) is a front view thereof and FIG.

12

(

b

) is a side view thereof. Further,

FIG. 13

is a plan view of the dry granulating apparatus shown in FIG.

11

(

b

). The same members as those used in the embodiment 1 will be denoted at the same reference symbols, and detailed explanation thereof will be omitted herefrom.

If powder grains having a large specific volume are processed, there is a case that air included in the hopper

19

cannot be sufficiently deaerated from the hopper

19

itself at one time and that it is therefore difficult to supply a constant amount of raw material. In addition, there is a possibility that the product quality is not maintained to be constant, or decrease of the yield is involved. In particular, if the degree of consolidation influences the product characteristics, e.g., if medicinal supplies are pressed, then the stability, disintegration (solubility), titer, or the like of a medicine thus being pressed, differs in pressed parts. Therefore, the product quality is not maintained to be constant. Or the yield (which is the ratio of an actually generated amount to a theoretically expected amount in the production process) is decreased.

A method of adjusting the compression force to the powder grains, by changing the length of a screw member in a screw feeder, has been adopted on the basis of the difference of the specific volume. However, in this method, it is necessary to replace the screw member every time when the kind of powder grains is changed. Therefore, a complicated replacement service cannot be avoidable. It is also necessary to prepare a large number of replaceable parts, which may cause increase of the apparatus costs. Hence, in the powder grain processing apparatus as the embodiment 2 of the present invention, the specific volume of the powder grains is reduced step by step by providing the powder grain transport means in two stages, as shown in FIGS.

11

(

a

) and

11

(

b

). So, the powder grains can be supplied stably to the compression roller mechanism.

As shown in FIGS.

11

(

a

) and

11

(

b

), the present dry granulating apparatus also has a housing body

1

set on a floor surface G. The housing

1

is divided into a powder grain processing room

70

and a drive room

4

where a control operation panel, a motor, and the like are installed.

A first powder grain transport means

7

is provided above the housing

1

. The means

7

performs primary the deaerating of the powder grains that have been vacuum-transported from the powder grain storage vessel

5

through a hose

71

by using, for example, an ejector, and then supplies the powder grains to the processing room

70

. Firstly, the transport means

7

has a supply hopper

8

which temporarily stores the supplied powder grains, and a powder grain press/feed means

9

connected to a lower part of the hopper

8

. In the top end side of the press/feed means

9

, a discharge port

10

is provided so as to stand on the housing

1

. The discharge port

10

is provided such that the lower part of the port penetrates through the housing

1

and is exposed to the inside of the processing room

70

.

In this case, the press/feed means

9

comprises a screw

13

internally connected to a drive shaft

12

of a motor

11

, and a transport tube

14

which perfectly seals the screw

13

. The transport tube

14

is provided so as to penetrate through the supply hopper

8

from the right side of the axis of the supply hopper

8

in FIG.

11

(

b

). The powder grains in the hopper

8

are fed to the discharge port

10

, being involved with the spiral fin of the screw

13

.

Also, the press/feed means

9

is provided with a deaerating nozzle

15

(a deaerating port) which communicates with an end part of the transport tube

14

and is located above the discharge port

10

. This nozzle

15

communicates with the transport tube

14

and the discharge port

10

, so that air included in the powder grains is deaerated and emitted to the atmosphere while the powder grains are transported by the screw

13

. Accordingly, in the present dry granulating apparatus, raw powder grains are subjected to primary deaerating before being thrown into the processing room

70

. Also, it is possible to supply stably a constant amount of powder grains to the next means, i.e., the second powder grain transport means

17

in the processing room

70

. Note that an air filter

16

is attached to the nozzle

15

so that powder grains might not be discharged to the atmosphere.

Meanwhile, the transport means

17

and the roller mechanism

18

are provided in the processing room

70

. In this case, the transport means

17

has a pitcher hopper

19

which receives and stores the powder grains fed from the transport means

7

, and a powder grain press/feed means

20

connected to a lower part of the hopper

19

in order to vertically feed the grains, like the transport means shown in FIG.

4

.

The press/feed means

20

is provided above the housing

1

and is deviated with respect to the press/feed means

9

, as shown in FIGS.

12

(

a

) and

12

(

b

) and

13

. Also, the discharge port

10

of the transport means

7

is positioned at the center of the hopper

19

, and the powder grains discharged from the discharge port

10

are supplied to the center of the hopper

19

. In the present dry granulating apparatus, the transport means

7

is provided above the housing

1

and deviated with respect to the center axis of the transport means

17

. Accordingly, the press/feed means

9

and the press/feed means

20

are arranged so as to be perpendicular to each other, so that the entire apparatus can be compact. The structure not described in the embodiment 2 is the same as that of the dry granulating apparatus according to the embodiment 1.

Thus, in the dry granulating apparatus according to the embodiment 2, the specific volume of the powder grains can be decreased step by step since the powder grain transport means has the first and second stages. It is therefore possible to achieve stable supply of the powder grains to the roller mechanism. Accordingly, flake-like compression moldings having a uniform shape can be formed by the compression roller mechanism.

Although the invention made by the present inventor has been specifically explained above, the present invention is not limited to the embodiments described above but can be variously changed without departing from the subject matter of the invention.

For example, in the above embodiments, a barrel made of porous metal is used as the barrel

24

. However, the barrel

24

may be a barrel in which a filter made of unwoven fabric, paper, cloth, a synthetic resin film, or the like that has pores. In addition, although the condition of the rollers

38

a

and

38

b

is detected by the sensor

51

attached to the frame

42

, the pressure of the powder grains in the introduction/compression part

50

may be directly measured by a pressure sensor. Also, the condition can be detected by measuring the displacement amount or distortion of the side seals

37

, the distance between the axes of the rollers

38

a

and

38

b,

or the distortion of the shafts.

The above description has been made of a case where the invention made by the present inventor is applied to a dry granulating apparatus which belongs to the applied field of the present invention. However, the present invention is not limited hitherto but may be applied to other powder grain processing apparatuses for pressing and shaping the powder grains.

Industrial Applicability

As has been described above, the powder grain processing apparatus of the present invention is provided with side seals which do not contact compression rollers. Powder grains enter between the rollers and the side seals, thereby forming closer layers which prevent leakage of the powder grains in the compression roller mechanism. Therefore, the side seals are not pressed in direction of the compression rollers by an actuator or the like, unlike conventional apparatuses. Accordingly, abrasion powders caused by contact between the compression rollers and the side seals can be prevented from mixing into products and the products can be prevented from becoming dirty, so that quality of the products can be stabilized.

The compression rollers or side seals need not be pressed by an actuator such as a hydraulic cylinder or the like, so that there is not a risk that the products may be polluted by oil contamination or abrasion powders from operating parts. In addition, since a distance between the frames is shorter than a conventional compression roller mechanism, the compression roller support shafts are short so that since no actuator is needed, the compression roller mechanism can have a strong rigid structure. Further, number of parts can be reduced in comparison with a conventional roller mechanism. The apparatus price can be reduced and the maintenance thereof can be easily performed.

Since a sensor for detecting motion of the compression roller mechanism is provided, it is possible to detect directly a pressure generated by the powder grains pressed or expanded. Accordingly, the physical characteristics, such as the hardness of the powder grains or the like, can be informed on real time.

If a porous deaerating barrel and a deaerating jacket surrounding the deaerating barrel are used as the powder grain transport means, the apparent specific volume of the powder grains can be much more increased so that the powder grains having a higher bulk density can be supplied to the compression roller mechanism. Accordingly, it is possible to obtain compression moldings having a more uniform shaping condition at a higher yield. In addition, the deaerating barrel and the deaerating jacket can be replaced with ones corresponding to the supply amount of the powder grains. Therefore, the bulk density and the apparent specific volume of the powder grains supplied to the compression roller mechanism can be appropriately adjusted.

Inside of a housing is divided into a powder grain processing room and a drive room by a partition wall, and the powder grain processing room has a watertight structure in which the inside of the powder grain processing room can be automatically cleaned by a cleaning device. Therefore, both inside and outside of each of various devices set in the powder grain processing room can be automatically cleaned, so that a powder grain processing apparatus which complies with GMP can be provided. In addition, since the inside of the housing is divided, maintenance and inspection can be easily performed.

A pitcher hopper and the like are arranged to move upward and downward in the powder grain processing room by the elevation mechanism. It is therefore possible to change appropriately the distance between the screw end part and the compression rollers. Accordingly, it is not necessary to prepare a large number of screws having different lengths or replace appropriately the screws in accordance with kinds of powder grains, so that it is possible to process widely various types of powder grains by only one screw. Also, services for replacing screws and number of types of the screws can be reduced.

Since load torque of the shearing device is detected, condition, such as fragility or the like, of the compression moldings can be expressed as a numerical value. Accordingly, the operation of the powder grain press/feed means and the compression rollers can be automatically controlled on the basis of the detection value. As a result of this, it is not necessary to carry out condition being set as depending on operator's intuition, so that compression moldings with stable quality can be obtained constantly. In addition, the condition of compression moldings need not be monitored minute by minute. Further, measurement of fragility or the like can be carried out during operation, so that time and labor necessary for performing granulation can be reduced and efficiency of the manufacturing can be improved.

Number	Date	Country	Kind
10-97955	Sep 1998	JP
10-97956	Sep 1998	JP

Number	Date	Country
48-89907	Nov 1973	JP
49-125281	Nov 1974	JP
50-56373	May 1975	JP
51-98682	Aug 1976	JP
51-123970	Oct 1976	JP
54-126674	Oct 1979	JP
61-136431	Jun 1986	JP
63-180198	Nov 1988	JP
01-044300	Feb 1989	JP
01-107999	Apr 1989	JP
05-069198	Mar 1993	JP
07-148599	Jun 1995	JP
09-194906	Jul 1997	JP

Device and method for processing powder and granular material

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (2)

PCT Information

US Referenced Citations (1)

Foreign Referenced Citations (13)