HOT SLURRY PUMP

Abstract

A hot slurry pump includes at least one working chamber, at least one displacement chamber which is arranged to be immobile with respect to the at least one working chamber, at least one transfer line, and one separator arranged in each of the at least one transfer line. The at least one transfer line either does not comprise a cooling section or comprises a cooling section having a length of less than 5 m.

Description

FIELD

The present invention relates to a hot slurry pump. The term “slurry” as used herein means in particular any thick material, that is, any mixture of liquid and solid components. This can include, for example, a slurry during excavation work or the like. Such slurry pumps are designed for continuous use and must reliably operate as smoothly as possible for long periods, extending to years, because a replacement of a defective slurry pump commonly involves considerable effort and time.

BACKGROUND

Hot slurry pumps have previously been described. DE 19782185 C2, for example, describes a hot slurry pump. A disadvantage of previously-described hot slurry pumps is that they are expensive to produce, require a lot of space, do not have a long operating life, or require a great deal of maintenance.

SUMMARY

An aspect of the present invention is to provide a hot slurry pump which is improved with respect to at least one of the aforementioned disadvantages.

In an embodiment, the present invention provides a hot slurry pump which includes at least one working chamber, at least one displacement chamber which is arranged to be immobile with respect to the at least one working chamber, at least one transfer line, and one separator arranged in each of the at least one transfer line. The at least one transfer line either does not comprise a cooling section or comprises a cooling section having a length of less than 5 m.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail below on the basis of embodiments and of the drawings in which:

FIG. 1 shows a schematic cross-section illustration of the principle of a hot slurry pump as described in the prior art.

FIG. 2 shows a perspective illustration of a part of an embodiment of the hot slurry pump according to the present invention;

FIG. 3 shows a detail of a longitudinal cross-section of the part of the hot slurry pump shown in FIG. 2, in comparison with the larger scale shown in FIG. 2;

FIG. 4 shows a side view of a part of a hot slurry pump according to the present invention;

FIG. 5 shows a view from above of the part of the hot slurry pump shown in FIG. 4; and

FIG. 6 shows a partial cutaway side view of a part of the hot slurry pump, in comparison with the larger scale shown in FIG. 4.

DETAILED DESCRIPTION

The hot slurry pump according to the present invention has at least one working chamber. The term “working chamber” as used herein means in particular the space into which the slurry is sucked and from which the slurry is pushed out. Each working chamber can, for example, have at least one pair of valves, for example, one intake valve and one outlet valve. The hot slurry pump also has at least one displacement chamber. The displacement chamber is immobile relative to the working space. Both the displacement space and the working chamber are installed in a fixed position, i.e., they are not arranged on a carriage, car, or the like. The displacement chamber comprises a displacement element. The displacement element can be a piston. However, the displacement element can, for example, be a diaphragm which can be actuated by a piston. The hot slurry pump can, for example, therefore have a piston diaphragm pump. The diaphragm can, for example, be a flat diaphragm. The hot slurry pump has a transfer line which can, for example, functionally connect the working chamber to the displacement chamber. In this displacement line, a liquid reciprocating fluid can, for example, reciprocate back and forth, and the pressure pulses alternate between the suction and pressure levels. The reciprocating fluid can also include, at least, slurry. A separator is arranged in the transfer line. The separator separates the hot slurry being pumped from the cooler reciprocating fluid. The temperature load on the diaphragm is thereby reduced. The separator can be a separator piston.

The at least one transfer line either has no cooling section, or a cooling section is included which has a length of less than three meters. In the alternative with a cooling section, the length of the cooling section can, for example, be less than two meters, or less than one meter.

The transfer line expands, for example, when the pump is started as a result of the heating of the transfer line by the reciprocating fluid associated with the startup. This expansion results in difficulties in known hot slurry pumps. By way of example, a compensator must be provided which compensates this thermal elongation, or other measures must be taken to prevent the occurrence of unacceptably high flange tension. It has been shown that the flange tension which occurs when the transfer line has no cooling section, or the length of the cooling section is less than three meters, for example, less than two meters, and, for example, less than one meter, is acceptable. This is because the change in length is then minimal.

It has also been found that it is possible to dispense with a cooling section or a longer cooling section, in particular since a significant temperature drop can already be achieved by the separator.

The term “cooling section” as used herein is in particular used to mean a section which is used exclusively or primarily for cooling, as concerns the transport of heat which cools the reciprocating fluid.

The cooling section can, for example, be a section in which no separator is arranged.

The cooling section can, for example, extend from the region of the transfer line in which the separator is arranged to the diaphragm housing. It is in principle conceivable that the transfer line is constructed as an integral part. However, the region of the displacement line in which the separator is arranged can, for example, not be constructed as an integral part of the remaining transfer line. It can, for example, rather be connected to the remaining transfer line by a separator line flange on the side thereof which faces away from the working chamber. The cooling section can then, for example, extend from the separator line flange to the diaphragm housing. It can be contemplated that a bend is arranged between the cooling section and the diaphragm housing. The cooling section can then, for example, extend from the region of the transfer line in which the separator is arranged, or from the separator line flange, to the end of the bend facing the cooling section.

The transfer line of the slurry pump can, for example, not have a heat exchanger.

The length of the entire transfer line can, for example, be less than five meters. The length of the entire transfer line can, for example, be less than four meters, and, for example, less than three meters, or less than two meters.

The transfer line can, for example, extend from the working chamber to the diaphragm housing. The transfer line can, for example, extend from the connection of the suction valve housing of the working chamber to the diaphragm housing.

If no compensation device is, for example, included to compensate the thermal length expansion of the transfer line, conditions for a particularly reliable hot slurry pump are created. The transfer line can therefore, for example, be constructed of rigid pipe so that no moving parts, such as, for example, metal bellows or telescopic connections, exist. The thermal expansion can also, for example, not be compensated by the pipe line, for example, by an expansion bend.

The medium to be pumped can be nickel slurry with a temperature of, for example, about 210° C.

The material of the diaphragm which is, for example, arranged in the displacement chamber can, for example, comprise a high-temperature material.

The material of the diaphragm can, for example, comprise fluoroelastomer. The diaphragm in one embodiment is formed of fluoroelastomer.

The region of the transfer line which has the separator can, for example, be connected by the shortest route to the displacement chamber. This achieves a particularly short transfer line with particularly low flange tension caused by thermal expansion, and a very compact pump.

The term “hot slurry pump” as used herein in particular refers to pumps that are suitable for pumping slurry with a temperature of up to 300° C. or 250° C. or 210° C. or 170° C. or 160° C. or 140° C.

The hot slurry pump is suitable for pumping hot slurry with a temperature, for example, of 160° C. to 210° C.

The present invention also relates to a method wherein slurry is pumped by a hot pump as described above. In this method, the reciprocating fluid is not actively cooled. The expression “not actively cooled” as used herein in particular means that no measures are taken which exclusively or primarily serve to cool the reciprocating fluid as concerns the transport of heat for the purpose of cooling down the reciprocating fluid.

A reciprocating fluid temperature which is tolerable for the diaphragm can, for example, be achieved in the displacement chamber, for example, exclusively, by separating the hot slurry being pumped from cooler reciprocating fluid by a separator.

Slurry can, for example, be pumped with a temperature range of from 130° C. to 300° C. or 130° C. to 250° C. or 130° C. to 210° C. or 130° C. to 170° C. or 130° C. to 160° C. or 130° C. to 140° C. or 160° C. up to 210° C.

The thermal length expansion of the transfer line can, for example, not be compensated.

The present invention is explained in greater detail below under reference to an embodiment shown in the drawings.

FIG. 1 shows the principle of the hot slurry pump previously described in the prior art. This prior art pump comprises a drive unit A and a pump B unit. The transfer line 3 has a cooling section K with a heat exchanger T which is intended to enhance the cooling effect of the transfer line 3. The length L of the cooling section K is greater than three meters.

To reduce to a harmless level the forces exerted as a result of the thermal length expansion of the transfer line 3 between the working chamber 1 and the displacement chamber 2, for example, during the startup of the pump, an expansion joint D, symbolized by a bend and not shown in detail, is arranged between the transfer line 3 and the displacement chamber 2.

The cooling section K extends from the region 6 of the transfer line 3, in which the separator is arranged, to the bend connecting the cooling section K to the diaphragm housing 14, is here designed as an expansion joint D. More specifically, the cooling section K extends from the separator line flange 21 up to the bend, and more precisely up to the end 24, of the bend facing the cooling section K.

FIGS. 2 and 3 show the drive unit A and a part of the pump unit B of a hot slurry pump according to the present invention. A double-acting duplex pump is shown in the embodiment. The drive unit A includes a drive shaft 13 which is rotated by a motor (not shown), for example, an electric motor. At least one gear wheel, indicated generally, is arranged on the drive shaft 13, which meshes with at least one substantially larger gear wheel, indicated generally, of the crankshaft 7. The crankshaft can also be driven directly. Two connecting rods 8 are arranged side by side on the crankshaft 7. The connecting rods 8 each transmit their movement by a crosshead 9 to a crosshead rod 12 which turns into a piston rod 11. One piston 10 is arranged on each piston rod 11, executing a linear reciprocating movement in a cylinder. A transmission medium 10a, for example, hydraulic oil, is arranged in each of the two cylinders 5, 5′. Two transmission medium chambers (not shown in FIGS. 2 and 3) adjoin each cylinder 5, 5′, each establishing a connection between the cylinders 5, 5′, and a diaphragm housing 14, 14′, 14″, 14′″. The transmission medium transmits the movement of the piston 10 to the displacement elements, which are each formed as a flat diaphragm 19. Because the pump is double acting, each cylinder 5, 5′ has a functional connection to two displacement chambers 2, 2′, 2″, 2′″, each of which comprises a diaphragm 19 and a diaphragm housing 14, 14′, 14″, 14′″. When the piston 10 in FIG. 2 moves to the right, the transmission medium flows into another diaphragm housing 14′, 14′″ and displaces the diaphragm 19 arranged therein. When the piston in FIG. 2 moves to the left, the transmission medium flows into another diaphragm housing 14, 14″ and displaces another diaphragm 19 arranged therein.

The diaphragm housings 14, 14′, 14″, 14′″ of the hot slurry pump according to the present invention can for their part be designed as the known pump shown in FIG. 1 in cross-section.

FIG. 4 shows the pump unit B of the hot slurry pump in a side view.

FIG. 5 shows, in a top view of this pump unit B, the four diaphragm housings 14, 14′, 14″, 14′″, already shown in FIG. 2, as well as the two cylinders 5, 5′, already shown in FIG. 2. Exactly one transfer line 3, 3′, 3″, 3′″ is connected to each diaphragm housing 14, 14′, 14″, 14′″, connecting each diaphragm housing 14 to exactly one working chamber 1, 1′, 1″, 1′″. Hot slurry flows into each working chamber 1, 1′, 1″, 1′″ through an inlet line 15 and an inlet check valve 17, 17′, 17″, 17′″, which is not shown in detail, and is then pushed out through an outlet check valve 18, 18′, 18″, 18′, which is likewise not shown in detail, into an outlet line 16.

The drive unit A and the pump unit B of the shown embodiment of the hot slurry pump according to the present invention are immobile, that is, installed permanently onto the substrate. The working chamber 1, 1′, 1″, 1′″ and the displacement chamber 2, 2′, 2″, 2′ are therefore immobile relative to each other.

As FIGS. 5 and 6 show well when viewed together, neither of the transfer lines 3, 3′, 3″, 3′″ of the embodiment shown of the hot slurry pump according to the present invention has a cooling section K.

The transfer lines 3, 3′, 3″, 3′″ each extend from the working chamber 1, 1′, 1″, 1′″ to the diaphragm housing 14, 14′, 14″, 14′. More specifically, each transfer line 3, 3′, 3″, 3′″ extends from the connection 23 of the housing of the inlet check valve 17, 17′, 17″, 17′″ to the diaphragm housing 14, 14′, 14″, 14′.

As shown most clearly in FIG. 6, the four transfer lines 3, 3′, 3″, 3′″ have two different lengths L₁, L₂ due to the geometry of the pump. Both the length L₁ and the length L₂ of the transfer lines is less than five meters.

The shown embodiment of the hot slurry pump according to the present invention does not have a heat exchanger T.

FIG. 6 also shows that no expansion joint D, or compensating device, is included for the purpose of compensating the thermal length expansion of the transfer line 3, 3′, 3″, 3′″.

The transfer line 3, 3′, 3″, 3′″ serves the purpose of subjecting the diaphragm 19 to a significantly lower temperature than is inherent in the hot slurry being pumped. This is achieved with the aid of a separator 4. In each case, the transfer line 3, 3′, 3″, 3′″ has a region 6, 6′, 6″, 6′″ with a separator 4 at its end which faces the working chamber 1, 1′, 1″, 1′″. This is designed as a separator piston.

The region 6, 6′, 6″, 6′″ of the transfer line which has the separator 4 is connected by the shortest route to the displacement chamber 2, 2, 2″, T″.

The reciprocating fluid 20 is not actively cooled. No device is therefore included which functions exclusively or primarily to cool the reciprocating fluid 20 in the sense of transporting heat to cool the reciprocating fluid 20.

The present invention is not limited to embodiments described herein; reference should be had to the appended claims.

LIST OF REFERENCE NUMBERS

• • 1, 1′, 1″, 1′ working chamber
  • 1 a hot slurry
  • 2, 2′, 2″, 2′″ displacement chamber
  • 3, 3′, 3″, 3′″ transfer line
  • 4 separator
  • 5, 5′ cylinder
  • 6, 6′, 6″, 6′″ region of the transfer line in which the separator is arranged
  • 7 crankshaft
  • 8 connecting rod
  • 9 crosshead
  • 10 piston
  • 10 a transmission medium
  • 11 piston rod
  • 12 crosshead rod
  • 13 driveshaft
  • 14, 14′, 14″, 14′″ diaphragm housing
  • 15 inlet line
  • 16 outlet line
  • 17, 17′, 17″, 17′″ inlet check valve
  • 18, 18′, 18″, 18′″ outlet check valve
  • 19 diaphragm
  • 20 reciprocating fluid
  • 21 separator line flange
  • 22 connector flange of the bend
  • 23 connection of the housing of the inlet check valve
  • 24 end of the bend
  • L length of the cooling section
  • L₁, L₂ length of the transfer line
  • A drive unit
  • B pump unit
  • D expansion joint
  • K cooling path/cooling section
  • T heat exchanger

Claims

1-7. (canceled)

8. A hot slurry pump comprising: at least one working chamber;at least one displacement chamber which is arranged to be immobile with respect to the at least one working chamber;at least one transfer line; andone separator arranged in each of the at least one transfer line,wherein,the at least one transfer line either does not comprise a cooling section (K) or comprises a cooling section having a length of less than 5 m.

9. The hot slurry pump as recited in claim 8, wherein the length of the at least one transfer line is less than 3 m.

10. The hot slurry pump as recited in claim 8, wherein a compensation device configured to compensate a thermal length expansion of the at least one transfer line is not provided.

11. The hot slurry pump as recited in claim 8, wherein, the at least one displacement chamber comprises a diaphragm, andthe diaphragm comprises a material comprising a high-temperature material.

12. The hot slurry pump as recited in claim 11, wherein the material further comprises a fluoroelastomer.

13. A method of pumping a hot slurry with the hot slurry pump as recited in claim 11, the method comprising: separating the hot slurry being pumped from a cooler reciprocating fluid via the one separator so as to achieve a reciprocating fluid temperature which can be tolerated by the diaphragm in the at least one displacement chamber,wherein, the reciprocating fluid is not actively cooled.

14. The method as recited in 13, wherein a thermal length expansion of the at least one transfer line is not compensated.