The presently disclosed embodiment relates to an electromagnetic vibrating diaphragm pump utilized for aeration of septic tanks for home use, oxygen supply for fish culturing tanks, exhalation for whirlpool baths, and other applied equipment, etc. More specifically, it relates to an electromagnetic vibrating diaphragm pump structured to prevent fluid from passing through the fixing part between the end of an oscillator and a diaphragm and leaking into the pump from outside.
An electromagnetic vibrating diaphragm pump is structured to comprise diaphragms made of rubber, for example, fixed to both ends of an oscillator having magnets fixed thereto, and electromagnets are provided in a manner to face the magnets on the oscillator. The oscillator and the electromagnets are surrounded by a housing and pump casings covers the outer diaphragms. Additionally, the oscillator oscillates in accordance with the polarity change of the electromagnets changing in accordance with the change in the phase of an AC source applied to the electromagnets such that the diaphragms vibrate so as to repeatedly suction and discharge fluid such as air.
The oscillator and the diaphragm are fixed in a structure shown in
Additional background information may be found in Japanese publication JP 2003-035266 A.
The structure where the mounting screw part 103c of the oscillator 103 is inserted into the through hole 110 of the above described outer and inner center plates 107a, 107b so as to be fixed with the nut 106 is preferred in terms of very easy assembly. However, in some cases, a gap may be formed between the mounting screw part 103c and the through hole 110 of the outer and inner center plates 107a, 107b. Additionally, depending on how tightly the nut 106 is fastened, a gap may be formed between the end of the supporting member 103b and the inner center plate 107b, too. Therefore, there is an issue that fluid such as air suctioned into the compression chamber leaks to the oscillator 103 side where the electromagnet, etc. is arranged, as indicated by arrows a1, a2 in
When such liquid leakage causes the amount of fluid discharged from the compression chamber to decrease to less than the amount of fluid suctioned into the compression chamber, the utilization ratio of fluid such as air suctioned into the compression chamber decreases, which is not preferred because it reduces pump efficiency. Moreover, in some cases, dangerous gas such as hydrogen for a hydrogen circulation pump, etc. may be discharged with a pump. It is dangerous to allow such gas to leak to the electromagnet side. Furthermore, because in some cases liquid may be suctioned or discharged, there is a problem that liquid flowing to the electromagnet side causes a short circuit in an electric system such as an electromagnet coil and so on.
On the other hand, as a method for preventing such liquid leakage, for example, it is possible to seal with a gasket between the washer 105 and the outer center plate 107a. However, if the oscillator 103 is fixed with a gasket inbetween, it becomes difficult to securely seal between the mounting screw part 103c and the through hole 110 of the outer and inner center plates 107a, 107b depending on how tightly the nut 106 is fastened. Moreover, if a gasket is provided between the washer 105 and the outer center plate 107a, the oscillator 103 can be tilted depending on how tightly the nut 106 is fastened, and the tilt, if any, allows the gap between the oscillator 103 and the electromagnet to vary easily, which leads to an issue of difficulty in stabilizing diaphragm pump performance among products.
Moreover, the issue of fluid leakage of the electromagnetic vibrating pump is not limited only to between the oscillator 103 and the outer and inner center plates 107a, 107b. For example, a conventional electromagnetic vibrating diaphragm pump had a diaphragm support 108 and a partition wall 109a constituting a compression chamber (not illustrated) of a pump casing 109 sandwiching the outer periphery end 104a of a diaphragm 104 as shown in
The presently disclosed embodiment was made in the light of the above conditions, and the object of the presently disclosed embodiment is to provide an electromagnetic vibrating diaphragm pump which improves pump efficiency by preventing fluid such as air from leaking out to the oscillator side while stabilizing pump performance among products by maintaining a gap between the oscillator and the electromagnet constantly among products, and does not cause damage to components or harm to human bodies, etc. even when suctioning and discharging liquid or dangerous gas such as hydrogen.
Moreover, another object of the presently disclosed embodiment is to improve the pump efficiency by preventing the leakage of air, etc. from the abutment surface of the pump casing and the diaphragm.
The electromagnetic vibrating diaphragm pump of the presently disclosed embodiment comprises an oscillator having two magnets on at least one surface side of a plate-like supporting member made of non-magnetic material and having mounting screw parts fixed to both ends of a central axis of the supporting member, disc-shaped diaphragms fixed to the mounting screw parts at both ends of the supporting member, an electromagnet provided to face the magnets and pump casings fixed to respective outer peripheries of the diaphragms provided at both ends and individually covering the outer side of the diaphragms, wherein the diaphragm is sandwiched by an inner center plate provided on the magnet side of the diaphragm and an outer center plate provided on the side opposite to the magnet side of the diaphragm, the end of the oscillator is inserted into and fixed to a through hole provided at the center of the inner and outer center plates, a cylindrical projecting portion is formed at the center of the inner center plate on the oscillator side, and a concave groove capable of fitting the projecting portion is formed at the end of the supporting member of the oscillator such that the projecting portion and the concave groove are sealed in an airtight manner with a ring-shaped elastic member inbetween.
It is preferred that a protruding portion holding the side surfaces of both ends of the supporting member constituting the oscillator is formed on the surface of the inner center plate on its oscillator side so as to position the supporting member. The side surface herein includes, in addition to the side surface in the thickness direction of the plate-like supporting member, the side at the end of the planar part of the plate-like supporting member.
It is preferred that the pump casing has a compression chamber adjacent to the diaphragm, an exhaust chamber connected to the compression chamber via an exhaust valve and a suction chamber connected to the compression chamber via a suction valve, and a rib digging into the diaphragm is formed on a joint surface jointing the diaphragm on the partition wall of the compression chamber.
The electromagnetic vibrating diaphragm pump of the presently disclosed embodiment is structured such that a cylindrical projecting portion is provided at the center of an inner center plate on its oscillator side and a concave groove capable of fitting the projecting portion is formed at the end of a supporting member of the oscillator, the projecting portion and the concave groove being sealed in an airtight manner with a ring-shaped elastic member inbetween. Therefore, with the groove formed beforehand on an outer periphery of a site where a mounting screw part is fixed at both ends of the supporting member of the oscillator and with an O-ring and the like inserted in this groove, by only press-fitting the mounting screw part into a through hole of the inner center plate, assembly work can be done and also airtight sealing can be ensured. Furthermore, because this sealing is a closely attached sealing in radial direction, of the concave groove formed on the supporting member of the oscillator, the ring-shaped elastic member fitting into the concave groove and the cylindrical projecting portion, the dimension among components such as a gap between the oscillator and the electromagnet is not affected, regardless of the strength of the elasticity. Therefore, it is possible to stabilize pump performance among products. In addition, even when an unexpected external force is applied to the oscillator, for example during assembling stage, it has an effect of preventing damage to the diaphragm because of its absorptive capacity for such a large external force. By providing such ring-shaped elastic member, the amount of fluid discharged from the compression chamber is not less than the amount of fluid suctioned into the compression chamber, and as a result, the decrease of pump performance can be prevented. Furthermore, if the fluid is liquid, it is possible to prevent pump failure due to short-circuited electromagnet coils, etc. when fluid penetrates to the oscillator side from taking place.
Furthermore, on the surface of the inner center plate on its oscillator side, a protruding portion for holding the side surfaces of both ends of the supporting member is formed such that the oscillator is prevented from rotating with respect to the inner center plate and the positioning of the supporting member can be performed easily, allowing stable operation of the pump. In addition, because the protruding portion of the inner center plate can be served as a guide when inserting the mounting screw part of the oscillator into the through hole formed on the center plates, the supporting member of the oscillator and the inner center plate are assembled easily.
Furthermore, by forming a rib digging into the diaphragm on the joint surface jointing the diaphragm on the partition wall of the compression chamber of the pump casing, situations are avoided where liquid suctioned into the compression chamber leaks out from the gap produced at the joint between the diaphragm and the pump casing and the amount of fluid discharged from the compression chamber is less than the amount of fluid suctioned into the compression chamber. As a result, it is possible to prevent decreasing of pump performance.
The embodiments of the presently disclosed embodiment will be described below with reference to
The diaphragm 3 is sandwiched by an inner center plate 6b provided on its magnet 2b1, 2b2 side of the diaphragm 3 and an outer center plate 6a provided on the side opposite to the magnet 2b1, 2b2 side of the diaphragm 3, and the mounting screw parts 2c fixed to the oscillator 2 are inserted into the through hole 6c provided at the center of the outer and inner center plates 6a, 6b and then fastened from outside through a washer 8 by a nut 9, such that the supporting member 2a of the oscillator 2 and the diaphragm 3 are fixed to each other.
As shown in
As shown in
A plate-like ferrite magnet or rare earth magnet, etc. can be used as these magnets 2b1, 2b2, and the magnets 2b1, 2b2 are individually magnetized. The magnet 2b1, for example, presents north pole on the surface of its electromagnet 4a side and south pole on the surface of its electromagnet 4b side while the magnet 2b2 presents south pole on the surface of its electromagnet 4a side and north pole on the surface of its electromagnet 4b side. On application of AC current to the electromagnets 4a, 4b, either one of the electromagnets 4a, 4b has north pole at its center and south poles on both sides of it, while the other one has south pole at its center and north poles on its both sides, and these north pole and south pole change alternately in accordance with the change in the phase of an AC generator, such that the magnetic action of the magnets 2b1, 2b2 provided on the supporting member 2a of the oscillator 2 causes attraction and repulsion forces between the magnets 2b1, 2b2 so as to allow the oscillator 2 to move in a reciprocating motion in axial direction. Accordingly, the diaphragm 3 vibrates so that the pump 1 suctions and discharges fluid repeatedly. These magnets 2b1, 2b2 also can be tightly fixed to the supporting member 2a, for example by being integrally molded onto the resin of the supporting member 2a during the formation of the supporting member 2a by resin molding, etc.
A diaphragm 4 can be formed of ethylene propylene rubber (EPDM) or fluoro-rubber, etc. The center plates 6a, 6b can be formed of metal or plastic, etc. Because this diaphragm 4 is sandwiched at its center by the outer center plate 6a and the inner center plate 6b, the through hole 6c communicates with from the outer center plate 6a to the inner center plate 6b through the diaphragm 3.
As shown in
Next, a method of fixing the outer and inner center plates 6a, 6b sandwiching the diaphragm 3 at its center to the oscillator 2 will be described with reference to
Moreover, a cylindrical portion 2e is formed because of this concave groove 2d at the center of the end of the supporting member 2a, and a ring-shaped groove 2e1 where a ring-shaped elastic member 7 can be inserted is formed on the outer periphery of the cylindrical portion 2e. With an O-ring 7, as the ring-shaped elastic member, mounted to this ring groove 2e1, the mounting screw part 2c is press fitted and embedded into the through hole 6c extending through the center plates 6a, 6b and the diaphragm 4. Then, the top end of the mounting screw part 2c projecting on the pump casing 5 side (right side of the drawing) is fastened through the washer 8 by the nut 9 so that the supporting member 2a of the oscillator 2 and the diaphragm 3 can be fixed to each other.
Here, because the O-ring 7 is formed to have a larger diameter than that of the cylindrical portion 2e, it is pressurized more strongly to contact with an inner wall surface 6b2 of the projecting portion 6b1 of the inner center plate 6b, as well.
With such structure, when fluid (liquid or gas) suctioned into the compression chamber 5A is about to invade from the pump casing 5 side through the gap between the through hole 6c formed on the diaphragm 3 and the outer and inner center plates 6a, 6b and the mounting screw part 2c to the inside of the housing 10 having the oscillator 2 positioned therein, this invasion can be prevented by the O-ring 7. Therefore, the amount of fluid discharged from the compression chamber 5A is not less than the amount of fluid suctioned into the compression chamber 5A, and as a result, it is possible to prevent the decrease of the performance of the pump 1. Additionally, if the fluid is liquid, a failure of the pump 1 due to a short circuit caused by the invasion of the fluid to the oscillator 2 side can be prevented from taking place. Furthermore, because the pressure of the O-ring 7 is only in radial direction perpendicular to axial direction of the oscillator 2, it is not affected by how tightly the mounting screw part 2c is fastened at a screw clamp part, and dimensional variation among members, etc. such as decentralization of oscillator 2 is not caused. Therefore, the performance of the pump 1 can be stabilized among products. Then, with the ring groove 2e1 formed beforehand on the outer periphery of the cylindrical portion 2e of the supporting member 2a of the oscillator 2, only by inserting the O-ring 7 into the ring groove 2e1 and press fitting it into the through hole 6c of the inner center plate 6b, the oscillator 2 and the diaphragm 3 can be assembled, and thus work efficiency during the assembly of the oscillator 2 and the diaphragm 3 is not worsened. Additionally, even when an unexpected external force is applied to the oscillator 2 during an assembling stage of the oscillator 2 and the diaphragm 3 and the like, the diaphragm is not damaged because of absorptive capacity of the O-ring 7 for such a large external force.
By the way, in this embodiment, as shown in
As shown in
In this embodiment, as shown in
Additionally, if the circular rib 5A3 is provided on the partition wall 5A of the pump casing 5 as done in this embodiment, the circular rib 5A3 is not affected by the deformation of the diaphragm 3 during the operation of the pump 1, and thus the sealing as a rib is stabilized so that operation status of the pump 1 can be stabilized eventually.
1 Electromagnetic vibrating diaphragm pump
2 Oscillator
2
a Supporting member
2
a
1, 2a2 Side surfaces
2
b
1, 2b2 Magnets
2
c Mounting screw part
2
d Concave groove
2
e Cylindrical portion
2
e
1 Ring-shaped groove
3 Diaphragm
3
a Flange
3
a
1 Abutment surface
4
a,
4
b Electromagnets
4
a
1, 4b1 Electromagnet cores
4
a
2, 4b2 Electromagnet coils
5 Pump casing
5A Compression chamber
5A1 Partition wall
5A2 Abutment surface
5A3 Circular rib
5B Suction chamber
5C Exhaust chamber
5
a Suction valve
5
b Exhaust valve
6
a Outer center plate
6
b Inner center plate
6
b
1 Projecting portion
6
b
2 Internal wall surface
6
b
3, 6b4 Protruding portions
6
c Through hole
7 O-ring
10 Housing
11 Diaphragm support
Number | Date | Country | Kind |
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2011-091237 | Apr 2011 | JP | national |
This application is the National Stage of International Application No. PCT/JP2012/059647 International Filing date, 9 Apr. 2012, which designated the United States of America, and which International Application was published under PCT Article 21 (s) as WO Publication 2012/141125 A1 and which claims priority from, and the benefit of, Japanese Application No. 2011-091237 filed 15 Apr. 2011, the disclosures of which are incorporated herein by reference in their entireties.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2012/059647 | 4/9/2012 | WO | 00 | 10/3/2013 |