JP2018185005A - Liner ring and centrifugal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liner ring that can prevent foreign matter from being caught on an impeller even if liquid with a large amount of foreign matter or liquid including hard foreign matter is handled.SOLUTION: A liner ring 20 comprises an elastic ring 21 made of an elastic material. A plurality of grooves 22 extending from one side surface of the elastic ring 21 to an opposite side surface are formed in an inner peripheral surface 21a of the elastic ring 21.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liner ring that is attached around a liquid inlet of an impeller, and more particularly to a liner ring that is suitable for use in a centrifugal pump that handles liquid containing foreign matter such as sewage. The present invention also relates to a centrifugal pump provided with such a liner ring.

  Centrifugal pumps are usually provided with a liner ring in order to prevent the liquid whose pressure is increased with the rotation of the impeller from leaking from the gap between the impeller and the pump casing to the suction side. The liner ring is disposed so as to surround the liquid inlet of the impeller and is fixed to the pump casing. A minute gap is formed between the inner peripheral surface of the liner ring and the outer peripheral surface of the impeller, and only a small amount of pressurized liquid on the discharge side passes through this gap to the suction side. Flows out. Generally, the liner ring is made of a metal such as copper alloy (CAC) or stainless steel (SUS). With the aging of the centrifugal pump, the gaps described above are worn, and the amount of liquid on the discharge side flows out to the suction side increases. In that case, the leakage can be suppressed by replacing the liner ring with a new one.

  In recent years when there is a high demand for high efficiency pumps, closed type impellers are often used for pumps that handle sewage. However, the closed type impeller is efficient, but if a foreign object enters between the impeller and the liner ring, it may cause biting. Therefore, conventionally, materials having a difference in hardness are selected for the impeller and the liner ring, and when a foreign object enters, one of them is shaved to prevent biting.

Japanese Utility Model Publication No. 62-148798

  However, when handling a liquid having a large amount of foreign matter or a liquid containing a hard foreign matter, the impeller and the liner ring are likely to bite. In particular, when the surface of the metal liner ring is scraped by a hard foreign object, the scraped material forms a lump on the surface of the liner ring, which becomes a sliding resistance with the impeller.

  Therefore, an object of the present invention is to provide a liner ring that can prevent biting of foreign matter on an impeller even when handling liquid containing a lot of foreign matter or liquid containing hard foreign matter. Moreover, an object of this invention is to provide the centrifugal pump provided with such a liner ring.

  In order to achieve the above-described object, according to one aspect of the present invention, there is provided an elastic ring made of an elastic material, and a plurality of inner circumferential surfaces of the elastic ring extending from one side surface of the elastic ring to the opposite side surface. The liner ring is characterized in that a groove is formed.

In a preferred aspect of the present invention, an outer ring to which the elastic ring is fixed is further provided.
In a preferred aspect of the present invention, the outer ring is made of metal.
In a preferred aspect of the present invention, the elastic ring is made of rubber.
In a preferred aspect of the present invention, the plurality of grooves are arranged at equal intervals around the central axis of the elastic ring.

In a preferred aspect of the present invention, each of the plurality of grooves has a semicircular cross section.
In a preferred aspect of the present invention, the plurality of grooves extend in parallel with a central axis of the elastic ring.
In a preferred aspect of the present invention, the plurality of grooves extend spirally.
In a preferred aspect of the present invention, the inner peripheral surface of the elastic ring and the groove are connected by a curved surface.

In a preferred aspect of the present invention, a set screw for fixing the elastic ring to the pump casing is further provided.
In a preferred aspect of the present invention, the set screw is located in the groove.
In a preferred aspect of the present invention, a core metal embedded in the elastic ring is further provided, and the strength of the elastic ring is improved.
In a preferred aspect of the present invention, the metal core has a protrusion that fits into a recess formed in the pump casing.
A preferred aspect of the present invention is characterized by further comprising a set screw driven into the outer peripheral surface of the outer ring.

  One aspect of the present invention is a centrifugal pump including a centrifugal impeller, a pump casing that houses the impeller, and the liner ring that is attached to the pump casing.

  According to the present invention, when a foreign substance such as sand contained in the liquid is sandwiched between the liner ring and the impeller, the elastic ring made of an elastic material is deformed by being depressed outward. Sticking can be prevented. Further, as the impeller rotates, the foreign matter moves to the groove, and the foreign matter is discharged through the groove together with the liquid. Thus, the combination of the elastic ring made of an elastic material and the groove can surely prevent the foreign object from being caught on the impeller. Further, the life of the liner ring can be extended by the liquid entering the groove acting as a lubricant.

It is sectional drawing which shows one Embodiment of a pump apparatus. It is an enlarged view which shows a liner ring and the surrounding structure. It is the figure which looked at the liner ring from the axial direction. It is a figure which shows the groove | channel of the elastic ring seen from the direction shown by the arrow A of FIG. FIG. 4 is a sectional view taken along line BB in FIG. 3. FIG. 6A and FIG. 6B are diagrams illustrating a mechanism in which foreign matter that has entered the gap between the liner ring and the impeller is discharged through the groove. It is a horizontal sectional view showing one embodiment of a groove. It is a figure which shows other embodiment of a groove | channel. It is sectional drawing which looked at the liner ring which concerns on other embodiment from the axial direction. FIG. 10 is an enlarged view showing the liner ring shown in FIG. 9 and the surrounding structure. It is sectional drawing which looked at the liner ring which concerns on other embodiment from the axial direction. It is the DD sectional view taken on the line of FIG. It is the EE sectional view taken on the line of FIG. It is a figure for demonstrating the process of attaching a liner ring to a pump casing. It is a figure for demonstrating the process of attaching a liner ring to a pump casing. It is sectional drawing which looked at the liner ring which concerns on other embodiment from the axial direction. It is an enlarged view which shows the liner ring shown in FIG. 16, and the surrounding structure. It is sectional drawing which shows other embodiment of the centrifugal pump provided with the said liner ring. It is sectional drawing which shows one Embodiment of the multistage centrifugal pump provided with the said liner ring.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a pump device. The pump device shown in FIG. 1 is an example of a submersible pump device suitable for an application for pumping a liquid containing foreign matters such as sand. As shown in FIG. 1, the pump device basically includes a centrifugal pump 1 and an electric motor 2 for driving the centrifugal pump 1. The centrifugal pump 1 includes an impeller 5, a pump casing 9 that houses the impeller 5, and a shaft 15 on which the impeller 5 is fixed. The shaft 15 is rotatably supported by a bearing 17.

  The pump device of this embodiment is installed so that the shaft 15 extends in the vertical direction. The electric motor 2 is connected to the shaft 15 and is configured to rotate the impeller 5 via the shaft 15. In the present embodiment, the shaft 15 of the centrifugal pump 1 also serves as the drive shaft of the electric motor 2. In one embodiment, the electric motor 2 may include a drive shaft connected to the shaft 15 of the centrifugal pump 1 with a bolt or the like.

  The impeller 5 is a centrifugal impeller and has a liquid inlet 6 facing downward. In this embodiment, the impeller 5 is a closed type impeller having a side plate (shroud) 7. The impeller 5 is disposed in the volute chamber 10 of the pump casing 9. The pump casing 9 has a suction port 11 and a discharge port 12. The suction port 11 faces downward, and the liquid inlet 6 of the impeller 5 is close to the suction port 11.

  When the electric motor 2 rotates the impeller 5, the liquid is sucked into the pump casing 9 through the suction port 11 and flows into the impeller 5 from the liquid inlet 6. The rotation of the impeller 5 gives velocity energy to the liquid, and the velocity energy is converted into pressure when the liquid flows in the volute chamber 10 where the flow path is widened. The pressurized liquid passes through the discharge port 12 and is discharged to the outside of the pump device.

  As described above, during operation of the pump device, the volute chamber 10 of the pump casing 9 is filled with the pressurized liquid. In order to prevent the pressurized liquid from returning to the suction port 11 through the gap between the impeller 5 and the pump casing 9, a liner ring 20 is attached to the pump casing 9. The liner ring 20 is disposed in the vicinity of the suction port 11 and is disposed around the liquid inlet 6 of the impeller 5. A minute gap is formed between the inner peripheral surface of the liner ring 20 and the outer peripheral surface of the impeller 5, and the impeller 5 is kept out of contact with the liner ring 20.

  FIG. 2 is an enlarged view showing the liner ring 20 and the surrounding structure in FIG. 1, and FIG. 3 is a view of the liner ring 20 as seen from the axial direction thereof. During operation of the pump device, a small part of the pressurized liquid in the volute chamber 10 flows to the suction side through this minute gap. The liner ring 20 includes an elastic ring 21 made of an elastic material such as rubber or resin, and an outer ring 25 that holds the outer peripheral surface of the elastic ring 21. The outer ring 25 is disposed outside the elastic ring 21. The outer ring 25 is made of a corrosion-resistant metal such as stainless steel. The reason why the outer ring 25 is made of metal is that it is easy to attach the liner ring 20 to the pump casing 9 on site. The outer peripheral surface of the elastic ring 21 is fixed to the inner peripheral surface of the outer ring 25 by an adhesive technique such as vulcanization or adhesive. The outer peripheral surface of the outer ring 25 is attached to the pump casing 9. The inner diameter of the elastic ring 21 is slightly larger than the outer peripheral surface of the impeller 5, and a minute gap is formed between the inner peripheral surface of the liner ring 20 and the outer peripheral surface of the impeller 5.

  A plurality of grooves 22 are formed in the inner peripheral surface 21 a of the elastic ring 21. These grooves 22 are provided in order to discharge the foreign matter contained in the liquid when the foreign matter enters the gap between the liner ring 20 and the impeller 5. The groove 22 extends from one side surface 21b of the elastic ring 21 to the opposite side surface 21c. In the present embodiment, as an example, the grooves 22 are arranged at equal intervals around the central axis C of the elastic ring 21. Moreover, in this embodiment, although the elastic ring 21 has the six grooves 22, the number of the grooves 22 is not limited to this embodiment.

  Here, the number of the grooves 22 may be determined based on the diameter of the liner ring 20. Specifically, the number of the grooves 22 is preferably increased in proportion to the diameter of the liner ring 20. For example, if the diameter of the liner ring 20 is 100 mm to 300 mm, the number of the grooves 22 may be selected from a range of 4 to 8. The interval at which the plurality of grooves 22 are arranged in the elastic ring 21 is such that when a foreign object enters the gap between the liner ring 20 and the impeller 5, the impeller 5 and the elastic ring 21 are not damaged. The grooves 22 may be formed as long as possible, and the grooves 22 may not be arranged at regular intervals around the central axis C of the elastic ring 21.

  Each groove 22 has a semicircular cross section. This is because the groove 22 is formed only from a smooth curved surface having no corners where fine foreign matters such as sand may accumulate. The depth of the groove 22 is larger than the maximum diameter of the foreign matter. As an example, since the suction port 11 of the pump device in the present embodiment faces downward, it can be assumed that the foreign matter sucked by the pump device is sand on the bottom surface of the suction water tank or well. If the maximum diameter of the sand is about 2 mm, the depth of the groove 22 is preferably about 3 mm. Further, the depth of the groove 22 may be determined based on the size of the gap between the liner ring 20 and the impeller 5 and the allowable leakage amount of the liquid flowing through the groove 22 to the suction side. The thickness of the elastic ring 21 is larger than the depth of the groove 22, and in one example, the thickness of the elastic ring 21 is 5 mm.

  As described above, during operation of the pump device, the impeller 5 rotates in a state where the gap between the inner peripheral surface of the liner ring 20 and the outer peripheral surface of the impeller 5 is kept in a minute gap and in a non-contact state. . At this time, it is possible to prevent the liquid in the groove 22 of the liner ring 20 from becoming a lubricant and causing the liner ring 20 to reach a high temperature. In particular, elastic materials such as rubber and resin may be cured by heat as compared with metal. Therefore, the effect of extending the life of the liner ring 20 can be expected by forming the groove 22 in the elastic ring 21 made of an elastic material. Further, since each groove 22 has a semicircular cross section, the flow of the liquid in the groove 22 becomes smooth, and the cooling effect is further increased by replacing the liquid in the groove 22 without stagnation.

4 is a view showing the groove 22 of the elastic ring 21 as viewed from the direction indicated by the arrow A in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB in FIG. The groove 22 is formed in the inner peripheral surface 21a of the elastic ring 21, and extends from one side surface 21b of the elastic ring 21 to the opposite side surface 21c. In the present embodiment, the groove 22 extends in parallel with the central axis C of the elastic ring 21. The groove 22 extending in parallel with the central axis C of the elastic ring 21 shown in FIG. 4 has the following advantages.
First, since the length of the groove 22 can be minimized, foreign matters can be quickly removed through the groove 22.
Secondly, when the operation of the pump device is stopped, foreign matter is easily discharged through the groove 22 together with the liquid in the volute chamber 10 of the pump casing 9.
Third, the groove 22 can be easily formed, and the cost of the liner ring 20 can be reduced.

  FIGS. 6A and 6B are diagrams illustrating a mechanism in which foreign matter that has entered the gap between the liner ring 20 and the impeller 5 is discharged through the groove 22. As shown in FIG. 6A, when the foreign substance 30 contained in the liquid is sandwiched between the liner ring 20 and the impeller 5, the elastic ring 21 made of an elastic material is compressed and its inner peripheral surface 21a. Dents outward and deforms. For this reason, excessive force is not applied to the impeller 5, and the impeller 5 is hardly scraped off by the foreign matter 30.

  As the impeller 5 rotates, the foreign matter 30 is moved toward the groove 22, and the foreign matter 30 is guided into the groove 22 as shown in FIG. During the operation of the pump device, the pressurized liquid in the volute chamber 10 flows toward the suction port 11 through the groove 22, so that the foreign matter 30 in the groove 22 is pushed by the flow of the liquid from the groove 22. Discharged. In this way, the combination of the elastic ring 21 made of an elastic material and the groove 22 of the elastic ring 21 allows the foreign matter to be quickly discharged and reliably prevents the foreign matter from biting the impeller 5. be able to.

  FIG. 7 is a horizontal sectional view showing an embodiment of the groove 22. In the embodiment shown in FIG. 7, the groove 22 and the inner peripheral surface 21 a of the elastic ring 21 are connected by a smooth curved surface 23. Such a curved surface 23 can smoothly guide the foreign matter that has moved along with the rotation of the impeller 5 to the groove 22.

  FIG. 8 is a view showing another embodiment of the groove 22. In the embodiment shown in FIG. 8, the groove 22 is a spiral groove, and extends spirally from one side surface 21 b of the elastic ring 21 to the opposite side surface 21 c. Although the length of each groove | channel 22 is not specifically limited, For example, each groove | channel 22 may extend the inner peripheral surface 21a of the elastic ring 21 by about 1 round. The spiral groove 22 shown in FIG. 8 has an advantage that the amount of liquid leakage to the suction side during operation of the pump device can be reduced.

  FIG. 9 is a cross-sectional view of a liner ring 20 according to another embodiment viewed from the axial direction, and FIG. 10 is an enlarged view showing the liner ring 20 shown in FIG. 9 and the surrounding structure. Since the configuration of the present embodiment that is not specifically described is the same as that of the above-described embodiment, the redundant description is omitted.

  The liner ring 20 of the present embodiment is the same as the above-described embodiment in that the elastic ring 21 is provided, but differs in that the outer ring 25 is not provided. In the present embodiment, the elastic ring 21 itself is directly fixed to the pump casing 9 by a plurality of set screws 30. The set screw 30 is located in a groove 22 formed in the inner peripheral surface 21 a of the elastic ring 21. It is preferable that the head of the set screw 30 is embedded in the elastic ring 21 so that the foreign matter moving in the groove 22 does not contact the set screw 30.

  The set screw 30 extends in the radial direction of the elastic ring 21, and the set screw 30 is driven from the inside to the outside of the elastic ring 21 as shown by the arrow in FIG. The set screw 30 passes through the elastic ring 21 in the radial direction and extends into the pump casing 9. The set screw 30 driven in this way can prevent the elastic ring 21 from being rotated with the rotation of the impeller 5.

  If the set screw 30 is disposed at a place other than the groove 22, when the elastic ring 21 is deformed by foreign matter, the impeller 5 may hit the set screw 30 or the set screw 30 may be loosened. Since the clearance between the set screw 30 and the impeller 5 can be secured by arranging the set screw 30 in the groove 22 as in the present embodiment, the set screw 30 does not hit the impeller 5.

  11 is a cross-sectional view of a liner ring 20 according to still another embodiment as viewed from the axial direction, FIG. 12 is a cross-sectional view taken along the line DD of FIG. 11, and FIG. 13 is a cross-sectional view taken along line EE of FIG. It is line sectional drawing. The configuration of the present embodiment that is not specifically described is the same as that of the embodiment shown in FIGS. 9 and 10, and thus redundant description thereof is omitted.

  In the present embodiment, an annular cored bar 31 is embedded in the elastic ring 21. The annular core 31 extends around the entire circumference of the elastic ring 21. With the core 31, the strength of the elastic ring 21 can be improved. Moreover, as shown in FIG. 13, the cored bar 31 may further include a plurality of protruding portions 31a. These protrusions 31 a protrude in a direction parallel to the central axis C of the elastic ring 21. The protrusion 31 a is exposed from the elastic ring 21 and is engaged with the pump casing 9.

  14 and 15 are views for explaining a process of attaching the liner ring 20 to the pump casing 9. As shown in FIG. 14, the inner surface of the pump casing 9 is formed with a recess 9 a into which the protruding portion 31 a of the core metal 31 is fitted. The liner ring 20 is pressed against the pump casing 9 in the axial direction of the liner ring 20 as shown by the arrow in FIG. 14, and the protrusion 31a is fitted into the recess 9a as shown in FIG. Due to the engagement between the protrusion 31 a and the recess 9 a of the pump casing 9, it is possible to prevent the elastic ring 21 from being rotated with the rotation of the impeller 5.

  FIG. 16 is a cross-sectional view of a liner ring 20 according to still another embodiment as viewed from the axial direction thereof, and FIG. 17 is an enlarged view showing the liner ring 20 shown in FIG. 16 and the surrounding structure. The configuration of the present embodiment that is not specifically described is the same as that of the embodiment described with reference to FIGS.

  The liner ring 20 of the present embodiment includes an elastic ring 21 made of an elastic material and an outer ring 25 made of metal. The plurality of set screws 30 are driven into the outer ring 25. More specifically, the set screw 30 is driven into both the outer peripheral surface of the outer ring 25 and the pump casing 9. The set screw 30 is not driven into the elastic ring 21. This is due to the following reason. When the gap between the liner ring 20 and the liner ring 20 becomes large due to aging, the liner ring 20 is replaced at the site. If the elastic ring 21 is accidentally damaged during the operation, the elastic ring 21 is damaged from the damage during the pump operation. There is a risk of tearing. Therefore, the durability of the liner ring 20 is improved by driving the set screw 30 only into the outer ring 25.

  Moreover, since the outer ring 25 and the elastic ring 21 of the liner ring 20 can be processed at a factory, the processing accuracy for bringing the outer ring 25 and the elastic ring 21 into close contact with each other is improved. Furthermore, at the site where the liner ring 20 is exchanged, it is difficult to cut the elastic material such as partially cutting, but in comparison, the metal is 0.01 to 0.00 mm in accordance with individual differences of the impeller 5. Since machining can be performed on the order of 001 millimeters, fine adjustment of the gap between the impeller 5 and the elastic ring 21 is facilitated when the liner ring 20 is replaced.

  According to each embodiment described above, even if a foreign substance contained in the liquid enters between the liner ring 20 and the impeller 5, the foreign object can be prevented from biting the impeller 5. Therefore, the pump device provided with the liner ring 20 is suitable for an application for pumping a liquid containing a large amount of foreign matters such as sand. For example, the pump device shown in FIG. 1 can be used for pumping sewage, river water, and the like.

  FIG. 18 is a cross-sectional view showing another embodiment of the centrifugal pump 1 provided with the liner ring 20. The configuration of the present embodiment that is not specifically described is the same as that of the embodiment shown in FIG. 1, and the same or corresponding members are denoted by the same reference numerals, and redundant description thereof is omitted.

  The centrifugal pump 1 shown in FIG. 18 includes a double suction type impeller 40. Both suction type impellers 40 have two liquid inlets 41 and two side plates (shrouds) 42. Two liner rings 20 are arranged around the two liquid inlets 41 of the impeller 40, respectively. Each liner ring 20 may include either a groove 22 extending in parallel with the central axis C of the elastic ring 21 shown in FIG. 4 or a spirally extending groove 22 shown in FIG. The liner ring 20 can prevent biting of foreign matter even in such a double suction type impeller 40.

  The centrifugal pump 1 shown in FIG. 1 is a single-stage centrifugal pump having a single-stage impeller 5, but the liner ring 20 of each of the above embodiments can also be applied to a centrifugal pump having a multi-stage impeller. it can. FIG. 19 is a cross-sectional view showing an embodiment of a multistage centrifugal pump provided with the liner ring 20. The configuration of the present embodiment that is not specifically described is the same as that of the embodiment shown in FIG. 1, and the same or corresponding members are denoted by the same reference numerals, and redundant description thereof is omitted.

  A centrifugal pump 1 shown in FIG. 19 is an embodiment of a multistage centrifugal pump including a multistage impeller 5. In the embodiment shown in FIG. 19, three impellers 5 are attached to the shaft 15 in series. The three impellers 5 are accommodated in the pump casing 9 and are rotationally driven by the electric motor 2 via the shaft 15. The three guide vanes 46 are arranged close to the outer periphery and the rear surface of each impeller 5. In such a configuration, the liquid introduced from the suction port 11 is pressurized as the impeller 5 of each stage rotates, passes through each guide vane 46, and is then discharged from the discharge port 12. A liner ring 20 is disposed around the liquid inlet of each stage of the impeller 5.

  The liner ring 20 in each embodiment described above can be removed from the pump casing 9. Therefore, when the elastic ring 21 of the liner ring 20 is worn, the liner ring 20 can be replaced with a new one.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Centrifugal pump 2 Electric motor 5 Impeller 6 Liquid inlet 7 Side plate (shroud)
9 pump casing 9a recess 10 volute chamber 11 suction port 12 discharge port 15 shaft 17 bearing 20 liner ring 21 elastic ring 21a elastic ring inner peripheral surface 21b, 21c elastic ring side surface 22 groove 25 outer ring 30 set screw 31 cored bar 31a protrusion Part 40 impeller 41 liquid inlet 42 side plate (shroud)
46 Guide vane C Center axis

Claims (15)

An elastic ring made of an elastic material;
A liner ring characterized in that a plurality of grooves extending from one side surface of the elastic ring to the opposite side surface are formed on the inner peripheral surface of the elastic ring.   The liner ring according to claim 1, further comprising an outer ring to which the elastic ring is fixed.   The liner ring according to claim 2, wherein the outer ring is made of metal.   The liner ring according to any one of claims 1 to 3, wherein the elastic ring is made of rubber.   The liner ring according to any one of claims 1 to 4, wherein the plurality of grooves are arranged at equal intervals around a central axis of the elastic ring.   The liner ring according to any one of claims 1 to 5, wherein each of the plurality of grooves has a semicircular cross section.   The liner ring according to any one of claims 1 to 6, wherein the plurality of grooves extend in parallel with a central axis of the elastic ring.   The liner ring according to any one of claims 1 to 6, wherein the plurality of grooves extend in a spiral shape.   The liner ring according to any one of claims 1 to 8, wherein the inner peripheral surface of the elastic ring and the groove are connected by a curved surface.   The liner ring according to claim 1, further comprising a set screw for fixing the elastic ring to the pump casing.   The liner ring according to claim 10, wherein the set screw is located in the groove.   The liner ring according to claim 1, further comprising a mandrel embedded in the elastic ring to improve the strength of the elastic ring.   The liner ring according to claim 12, wherein the metal core has a protrusion that fits into a recess formed in the pump casing.   The liner ring according to claim 2 or 3, further comprising a set screw driven into an outer peripheral surface of the outer ring. A centrifugal impeller,
A pump casing that houses the impeller;
A centrifugal pump comprising: the liner ring according to any one of claims 1 to 14 attached to the pump casing.

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