WO2007014876A1

WO2007014876A1 - Hydraulic pump

Info

Publication number: WO2007014876A1
Application number: PCT/EP2006/064623
Authority: WO
Inventors: Francesco Sinico; Anders Lykkegaard Moller
Original assignee: DAB Pumps SpA
Current assignee: DAB Pumps SpA
Priority date: 2005-07-29
Filing date: 2006-07-25
Publication date: 2007-02-08
Anticipated expiration: 2008-01-29
Also published as: EP1910684A1; ITPD20050240A1

Abstract

A hydraulic pump (10), of the type comprising a jacket (11) for containing an impeller assembly (12), which is enclosed at its ends respectively by a closure head (13) and by a pump body (14) in which an intake port (17) and a delivery port (18) are formed, the ports being connected functionally respectively to the inlet and the outlet of the impeller assembly (12). A compartment (19) is provided on the pump body (14) and a box-like body (20) is inserted therein and is open toward the jacket (11); in turn, two mutually isolated chambers (21, 22) are formed in the box-like body: a first chamber (21) is connected directly to the intake port (17) and a second chamber (22) is connected directly to the delivery port (18).

Description

HYDRAULIC PUMP

Technical Field

The present invention relates to a hydraulic pump, particularly but not exclusively of the vertical multistage type. Background Art

As it is known, hydraulic pumps for water systems of users of various sizes are constituted generally by an outer steel casing, in which the water intake and delivery ports and the chamber of the impeller assembly (with one or more impellers, depending on the number of stages) are provided, an electric motor, arranged inside or outside such casing, being connected to said impeller assembly.

In a typical structure of a vertical hydraulic pump, the pump casing is usually constituted by a jacket for containing the impeller assembly, which is enclosed at its ends respectively by a closure head and by a pump body, in which there is an intake port and a delivery port, which are connected functionally respectively to the inlet and the outlet of the impeller assembly. The various components are mutually connected so as to ensure watertightness.

Typically, the closure head is connected to the pump body by means of bolted braces; the electric motor is fixed to the head and is connected to the impeller assembly.

The various characteristics that a pump must have include the resistance of the various components to corrosion caused by water.

Further, the jacket, the closure head and the pump body must be made of a material that has structural strength characteristics, since they have to bear a certain load.

The material that has both load resistance characteristics and corrosion resistance characteristics is stainless steel.

Among the cited pump components, the pump body is one of the most critical in terms of cost. This component in fact has a complex internal geometry and has to be machined so as to ensure, in certain parts thereof, a finish that allows correct mating with other components in order to avoid inaccurate hydraulic connections and consequent leaks. Further, such pump body is also one of the heaviest components, since it also acts as a footing for the pump.

In order to try to reduce production costs, many pump types have a pump body made of cast iron, which is generally far cheaper than stainless steel. Of course, the corrosion of cast iron is certainly much faster than any corrosion of medium-quality stainless steel, and therefore these pumps have to be replaced after a certain time.

In order to extend the life of these pumps having a cast-iron pump body, corrosion prevention treatments are performed on the pump body which increase the overall costs of the finished pump and in any case do not ensure a durability performance equal to what can be obtained with stainless steel pump bodies. Disclosure of the Invention

The aim of the present invention is to provide a hydraulic pump that solves the problems noted in known types.

Within this aim, an object of the present invention is to provide a hydraulic pump that has a reduced use of stainless steel with respect to known types and at the same time ensures a performance, in terms of corrosion resistance, that can be compared to known types. Another object of the present invention is to provide a hydraulic pump that has reduced costs with respect to known types for an equal corrosion resistance performance.

Another object of the present invention is to provide a hydraulic pump that reduces the number of processes to be performed on the pump body. Another object of the present invention is to provide a hydraulic pump that can be manufactured with known systems and technologies.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a hydraulic pump, of the type that comprises a jacket for containing the impeller assembly, which is enclosed at its ends respectively by a closure head and by a pump body in which an intake port and a delivery port are formed, said ports being connected functionally respectively to the inlet and the outlet of said impeller assembly, characterized in that in said pump body there is a compartment in which a box-like body made of plastic material is inserted which is open toward said jacket and on which in turn two mutually isolated chambers are formed, a first one of said chambers being connected directly to said intake port and a second one of said chambers being connected directly to said delivery port. Brief Description of the Drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of some preferred but not exclusive embodiments thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is an exploded perspective view of the lower portion of a hydraulic pump according to the invention, in particular related to the pump body thereof;

Figure 2 is an external perspective view of a hydraulic pump according to the invention; Figure 3 is a sectional side view of the lower portion of the pump of

Figure 1;

Figure 4 is a sectional plan view of the pump body of a pump according to the invention;

Figure 5 is a sectional side view of the lower portion of a second embodiment of a pump according to the invention; Figure 6 is a sectional side view of the lower portion of a third embodiment of a pump according to the invention;

Figure 7 is a sectional side view of the lower portion of a fourth embodiment of a pump according to the invention; Figure 8 is a sectional side view of the lower portion of a fifth embodiment of a pump according to the invention.

It is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer. Ways of carrying out the Invention

With reference to Figures 1 to 4, a hydraulic pump according to the invention is generally designated by the reference numeral 10.

The hydraulic pump 10 comprises a jacket 11 for containing an impeller assembly 12, which is shown schematically in broken lines in Figures 1 and 3; in this embodiment, the pump is of the multistage vertical type and the impeller assembly corresponds to a multistage impeller.

The jacket 11, which has a cylindrical contour, is enclosed at its ends respectively by a closure head 13 and by a pump body 14, as clearly visible in Figure 2. The closure head 13 and the pump body 14 are connected by tension members 15 in a per se known manner.

An electric motor 16 is fixed externally on the closure head 13 and its output shaft passes through the head 13 in order to connect to the impeller assembly 12 inside the jacket 11. An intake port 17 and a delivery port 18 are formed on the pump body

14 and are functionally connected respectively to the inlet and the outlet of the impeller assembly.

A cylindrical compartment 19 is formed in the pump body 14 and a box-like body 20 is inserted therein; the body is substantially shaped complementarity to the compartment 19 and is open toward the jacket 11; in turn, two mutually isolated chambers are formed in the body: a first chamber

21, which is directly connected to the intake port 17, and a second chamber

22, which is connected directly to the delivery port 18.

The box-like body 20 is made of a material which is resistant to corrosion.

In this embodiment, the corrosion-resistant material is plastic material (preferably for injection molding), but in other embodiments, as described hereinafter, said material may be stainless steel (or optionally a combination of stainless steel and plastic material); it is evident that other materials with corrosion-resistance properties also can be used according to requirements. In this embodiment, the box-like body 20 comprises a bottom 23, from which an outer annular wall 24 protrudes, and, centrally thereto, an inner annular wall 25 protrudes; in particular, both the outer annular wall 24 and the inner annular wall 25 are substantially circular and are coaxial. The space comprised between the outer annular wall 24 and the inner annular wall 25 forms the second chamber 22, while the space inside the inner annular wall 25 forms the first chamber 21.

The second chamber 22, as described more clearly hereinafter, is crossed by the pressurized water proximate to the delivery; for this reason, the outer annular wall 24 rests against the inner lateral surface of the compartment 19, so as to withstand the thrust of the pressure that otherwise might break the outer annular wall 24.

A first opening 26 and a second opening 27 are formed on the outer annular wall 24 and are centered respectively on the intake port 17 and on the delivery port 18.

A tubular connecting portion 28 protrudes from the first opening 26 and is open onto the first chamber 21.

The intake port 17 and the delivery port 18 are constituted by two respective bushings 29, which are monolithic with the pump body 14 and have a structural containment function; an intake sleeve 30 and a delivery sleeve 31 are inserted respectively therein, are connected directly respectively to the first chamber 21 and to the second chamber 22, and act as hydraulic manifolds; in practice, the water flows in the sleeves 30 and 31.

The sleeves 30 and 31 are made of a corrosion-resistant material, such as preferably stainless steel.

The bushings 29 have a flange-shaped end 32.

In this embodiment, the sleeves 30 and 31 have identical shapes and dimensions and both have an end which lies outside the respective bushing

29 and forms an annular abutment 33 whose diameter is greater than the outside diameter of the respective sleeve that is arranged in contact with the flange-shaped end 32 of the corresponding bushing 29.

In particular, the intake and delivery sleeves 30 and 31 are inserted respectively in the first and second openings 26 and 27; the intake sleeve 30 is coupled with a watertight seal to the tubular portion 28, while the delivery sleeve 31 is coupled with a watertight seal to a collar 34, which is monolithic with the box-like body 20, is arranged inside the second chamber 22, and in practice forms the second opening 27.

The hydraulic seal of the sleeves 30 and 31 is provided by corresponding gasket rings 35, which are arranged between a shoulder 36, formed proximate to the internal end of each sleeve, and a corresponding complementary shoulder 37, which is formed respectively on the tubular portion 28 and on the collar 34.

In particular, the collar 34 is formed by a circular hole, which is formed in a wall 38 arranged in front of the second opening 27. The inner annular wall 25, at its portion arranged in front of the second opening 27, is shaped like a cusp 39, so as to guide the flow of water from the second chamber 22 toward the intake port 18; in particular, the cusp 39 is monolithic with the wall 38.

Advantageously, the free end edge of the outer annular wall 24 of the box-like body 20 forms a laterally protruding tang 40, which is useful to lock in a sandwich-like fashion, together with an upper rim 41 of the pump body 14, an additional sealing ring 42.

Advantageously, there is a flat element 43 for stiffening the box-like body 20, which is coupled to the free edges of the outer annular wall 24 and of the inner annular wall 25; the flat element 43 is preferably made of plastic material.

The flat element 43 is circular and is constituted by an outer annular portion 44, which makes contact internally with the free end edge of the outer annular wall 24, and an inner annular portion 45, which makes contact with the inner annular wall 25.

The outer annular portion 44 and the inner annular portion 45 are connected by radial portions 46, so as to form angular water flow sectors 47 in output from the impeller assembly 12 and entering the second chamber 22. An angular sector 47a, which corresponds to the region of the second opening 27, is closed in order to reduce the turbulence of the water in output.

In order to properly couple the flat element 43 to the box-like body 20, on the inner annular wall 25 there are vertical holes 48, which are adapted to remove material from the wall 25 and receive complementary shaped studs 49, which protrude from the inner annular portion 45.

Figure 5 illustrates a second embodiment of a pump according to the invention, generally designated by the reference numeral 100.

In this embodiment, the laterally protruding tang 140 of the outer annular wall 124 of the box-like body 120 has, with the upper rim 141 of the pump body 114, a mating of the male-female type with vertical insertion.

In particular, an annular rib 150 protrudes from the upper rim 141 and is inserted in a complementarily shaped coupling seat 151, which is formed on the lower portion of the laterally protruding tang 140. This mating of the male-female type with vertical insertion allows to engage the upper part of the box-like body 120 with the pump body 114, thus avoiding, as in the preceding example, the use of a flat element for stiffening the free edges of the outer annular wall 124.

The impeller assembly 112 is arranged on an annular support 152, which is flared upward and is coupled to the upper end of the inner annular wall 125 that forms the first chamber 121.

In this embodiment, the watertightness of each sleeve 130 and 131 is provided by a corresponding sealing ring 135, which is arranged hermetically on the outer wall of the corresponding sleeve and is locked between a corresponding complementary shoulder 137 formed on the box- like body 120 proximate to the corresponding opening 126 (or 127) and a locking ring 153, which is arranged at the opening 126 and is blocked on one side by the internal wall of the pump body 114.

The material that forms the box-like body 120 is plastic material or stainless steel or another material that has corrosion-resistance characteristics.

Figure 6 illustrates a third embodiment of a pump according to the invention, generally designated by the reference numeral 200.

In this embodiment, inside the first chamber 221 of the box-like body 220 there is a tubular core 255, which is shaped complementarily with respect to the wall 225 of the chamber.

The tubular core 255 has a further opening 256, which is arranged at the tubular portion 228 and is open in an upper region.

The upper portions of the wall of the tubular core 255 are flared upward so as to form an annular support 252 for the impeller assembly 212.

Such tubular core also is made of a material that has corrosion- resistance characteristics, such as preferably stainless steel.

Figure 7 illustrates a fourth embodiment of a pump according to the invention, generally designated by the reference numeral 300. In this embodiment, the box-like body 320 is constituted by two separate bodies: a first box-like body 320a is constituted by the bottom 323, provided centrally with a through hole 356, from which the outer annular wall 324 protrudes, and a second box-like body 320b, which is constituted by a cup which is open upward and is formed by a bottom and by the internal wall 325, on which the tubular portion 328 for connection to the first opening 326 is provided.

The lower part of the second box-like body 320b is inserted in the hole provided centrally with respect to the bottom 323 of the first box-like body 320a; watertightness is ensured by a first gasket 357, which is arranged between the wall of the hole 356 and the wall of the second box- like body 320b.

On the internal surface of the tubular portion 328 there is an annular slot for accommodating a second gasket 358 for providing a seal for the sleeve 330. The upper portions of the internal wall 325 of the second box-like body 320b are flared upward so as to form an annular support 352 for the impeller assembly 312.

The materials that form the first box-like body 320a and the second box-like body 320b are of the type with corrosion resistance; for example, they can be plastic material and/or stainless steel, depending on the structural requirements.

Figure 8 illustrates a fifth embodiment of a pump according to the invention, generally designated by the reference numeral 400.

In this embodiment, the box-like body 420 has a simplified structure with respect to the embodiments described so far.

This structure in fact has the box-like body 420 monolithically made of a material which has corrosion-resistance and high structural strength characteristics, such as for example stainless steel.

Thanks to this characteristic, the box-like body does not require elements for stiffening the outer walls 424. The impeller assembly 412 is arranged on an annular support 452, which is flared upward and is coupled to the upper end of the internal annular wall 425 that forms the first chamber 421.

In practice it has been found that the invention thus described solves the problems noted in known types of hydraulic pump; in particular, the present invention provides a hydraulic pump that allows to have high- quality "corrosion-resistance" performance even with a limited use of stainless steel.

It is in fact possible to provide the pump body 14 by using cast iron, according to a simple geometry, and provide separately, with cheaper production methods, the box-like body 20 (or, equivalently, 120, 220, 320).

The box-like body 20 is made of a corrosion-resistant material, such as for example plastic material or stainless steel (but other materials with corrosion-resistance properties can be used); as regards the case of the use of plastic material, the production of a component with complex geometry such as the box-like body is facilitated by the low cost of the plastic molding process with respect to the cost of the cast-iron casting process and of any subsequent finishing work.

Advantageously, the intake and delivery ports comprise the sleeves 30 and 31, which are made of stainless steel and have a simple geometry and whose annular abutment 32 can therefore be manufactured cheaply with such a surface finish as to ensure correct mating with the pipes to which the pump is to be connected.

In this manner, the manufacturing costs of the pump are reduced both due to the use of less expensive materials and due to the elimination of finishing work, ensuring high-quality corrosion-resistance characteristics.

Moreover, at the same time the overall weight of the pump is reduced by means of the introduction of plastic materials replacing stainless steel or cast iron parts. Such a structure of the pump further allows to choose the materials (stainless steel, cast iron, plastics and others) that are best suited to the type of liquid to be pumped and to the particular operating requirements, thus increasing design flexibility.

A very important aspect that derives from the particular modular structure of the pump is that the designer can compose the pump by choosing the components according to requirements in terms of corrosion resistance, structural strength and cost.

As shown in the various embodiments, it is possible to provide the box-like body in the most convenient manner, by using only plastic material (which has corrosion resistance but low structural strength), only stainless steel (which has corrosion resistance and high structural strength) or a combination thereof (or of materials with equivalent properties).

It is also possible to use components that have corrosion resistance of the traditional type but can be manufactured cheaply, and therefore can be replaced easily, in view of the modularity of the structure of the pump, once their life cycle has ended.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. PD2005A000240 from which this application claims priority are incorporated herein by reference.

Claims

1. A hydraulic pump (10, 100, 200, 300, 400), of the type comprising a jacket (11) for containing an impeller assembly (12, 112, 212, 312, 412), which is enclosed at its ends respectively by a closure head (13) and by a pump body (14, 114) in which an intake port (17) and a delivery port (18) are formed, said ports being connected functionally respectively to the inlet and the outlet of said impeller assembly (12, 112, 212, 312, 412), characterized in that in said pump body (14, 114) there is a compartment (19) in which a box-like body (20, 120, 220, 320, 420) is inserted which is open toward said jacket (11) and on which in turn two mutually isolated chambers (21, 121, 221, 22) are formed, a first one (21, 121, 221) of said chambers being connected directly to said intake port (17) and a second one (22) of said chambers being connected directly to said delivery port (18).

2. The hydraulic pump according to claim 1, characterized in that said intake port (17) and said delivery port (18) are constituted by two respective bushings (29), which are monolithic with said pump body (14, 114) and have a structural containment function, and in which an intake sleeve (30, 130) and a delivery sleeve (31, 131) are inserted respectively, said sleeves being connected directly respectively to said first chamber (21, 121, 221) and said second chamber (22) and acting as hydraulic manifolds.

3. The hydraulic pump according to one of the preceding claims, characterized in that said box-like body (20, 120, 220, 420) comprises a bottom (23), from which an outer annular wall (24, 124) and, centrally thereto, an inner annular wall (25, 125, 225) protrude, the space comprised between said outer annular wall (24, 124) and said inner annular wall (25, 125, 225) forming said second chamber (22), the space inside said inner annular wall (25, 125, 225) forming said first chamber (21, 121, 221), a first opening and a second opening (26, 126, 27, 127) being formed in said outer annular wall (24, 124) and being centered respectively on said intake port (17) and said delivery port (18), a tubular connecting portion (28, 228) protruding from said first opening (26) and being open onto said first chamber (21, 121, 221).

4. The hydraulic pump according to one or more of the preceding claims, characterized in that said intake sleeve (30, 130) and said delivery sleeve (31, 131) are inserted with a watertight seal in said first and second openings (26, 126, 27, 127) respectively.

5. The hydraulic pump according to claims 3 and 4, characterized in that said intake sleeve (30, 130) is mated with a watertight seal to said tubular portion (28, 228), said delivery sleeve (31, 131) being mated with a watertight seal to a collar (34), which is monolithic with said box-like body (20) and is arranged in said second chamber (22).

6. The hydraulic pump according to one or more of claims 2 to 5, characterized in that said bushings (29) are provided with a flanged end (32), said intake sleeve (30, 130) and said delivery sleeve (31, 131) both having an end which is arranged outside the respective said bushing (29) and forms an annular abutment (33), whose diameter is larger than the outside diameter of the respective sleeve (30, 130, 31, 131), which is arranged in contact with said flanged end (32) of the corresponding said bushing (29), the watertight seal of said intake sleeve (30, 130) and said delivery sleeve (31, 131) being formed by corresponding sealing rings (35), which are arranged between the outer walls of said intake sleeve (30, 130) and said delivery sleeve (31, 131) and said pump body (20, 120, 220, 320, 420).

7. The hydraulic pump according to claim 6, characterized in that the watertight seal of said intake sleeve (30) and said delivery sleeve (31) is provided by corresponding sealing rings (35), which are arranged between a shoulder (36) formed proximate to the internal end of each of said sleeves (30, 31) and a corresponding complementary shoulder (37), which is formed respectively on said tubular portion (28) and on said collar (34).

8. The hydraulic pump according to claims 5 and 6, characterized in that said collar (34) is formed by a circular hole, which is formed in a wall (38) which is arranged in front of said second opening (27), said inner annular wall (25), in its portion arranged in front of said second opening (27), being shaped like a cusp (39), so as to guide the flow of water from said second chamber (22) toward said intake port (18).

9. The hydraulic pump according to one or more of the preceding claims, characterized in that said intake sleeve (30) and said delivery sleeve (31) are made of stainless steel.

10. The hydraulic pump according to one or more of the preceding claims, characterized in that said intake sleeve (30) and said delivery sleeve

(31) are substantially identical.

11. The hydraulic pump according to one or more of the preceding claims, characterized in that the free end edge of said outer annular wall (24) of said box-like body (20) forms a tang, which protrudes laterally (40) and is adapted to block in a sandwich-like fashion, together with the upper rim (41) of said pump body (14), an additional sealing ring (42).

12. The hydraulic pump according to one or more of the preceding claims, characterized in that said compartment (19) is cylindrical and said box-like body (20) is shaped substantially complementarily with respect to said compartment (19) and said outer annular wall (24) and said inner annular wall (25) are both substantially circular and mutually coaxial.

13. The hydraulic pump according to one or more of the preceding claims, characterized in that said impeller assembly (112, 212, 312, 412) is arranged on an annular support (152, 252, 352), which is flared upward and is provided at the upper end of said inner annular wall (125, 225, 325, 425) that forms said first chamber (121).

14. The hydraulic pump according to one or more of the preceding claims, characterized in that it comprises a flat element (43) for stiffening said box-like body (20), which is coupled to the free edges of said outer annular wall (24) and said inner annular wall (25).

15. The hydraulic pump according to claim 14, characterized in that said box-like body (20) and said flat element (43) are made of plastic material.

16. The hydraulic pump according to one of claims 14 or 15, characterized in that said flat element (43) has a circular contour and is constituted by an outer annular portion (44), which is arranged in internal contact with the free end edge of said outer annular wall (24), and an inner annular portion (45), which is arranged in contact with said inner annular wall (25), said outer annular portion (24) and said inner annular portion (25) being connected by radial portions (46), which are adapted to form angular sectors (47) for the passage of the water that exits from said impeller assembly (12) and enters said second chamber (22).

17. The hydraulic pump according to claim 16, characterized in that the angular sector (47a) of said angular sectors (47) for the passage of the water in output from said impeller assembly (12), which corresponds to the region of said second opening (27), is closed in order to reduce the turbulence of the outflowing water.

18. The hydraulic pump according to claim 17, characterized in that vertical holes (48) are provided on said inner annular wall (25), are adapted to remove material from said inner annular wall (25) and are adapted to receive complementarily shaped studs (49), which protrude from said inner annular portion (45).

19. The hydraulic pump according to one or more of the preceding claims, characterized in that the outer annular wall (124) of said box-like body (120) is provided, in an upper region, with a coupling of the male- female type with vertical insertion with the upper rim (141) of said pump body (114).

20. The hydraulic pump according to claim 19, characterized in that an annular rib (150) protrudes from said upper rim (141) and is inserted in a complementarily shaped coupling seat (151) formed on the lower portion of a tang (140), which protrudes laterally from the upper part of said outer annular wall (124).

21. The hydraulic pump according to one or more of the preceding claims, characterized in that the watertight seal of each of said sleeves (130, 131) is provided by a corresponding sealing ring (135), which is arranged hermetically on the outer wall of the corresponding said sleeve (130, 131) and is locked between a corresponding complementary shoulder (137), formed on said box-like body (120) proximate to the corresponding said opening (126, 127), and a locking ring (153), which is arranged at said opening (126) and is locked on one side by the inner wall of said pump body (114).

22. The hydraulic pump according to one or more of the preceding claims, characterized in that a tubular core (255) is provided inside said first chamber (221) of said box-like body (220) and is shaped complementarily to the wall (225) of said first chamber (221), said tubular core (255) having an additional opening (256), which is arranged at said tubular portion (228) and is open in an upper region.

23. The hydraulic pump according to claim 22, characterized in that the upper portions of the wall of said tubular core (255) are flared upward so as to form an annular support (252) for said impeller assembly (212).

24. The hydraulic pump according to one or more of the preceding claims, characterized in that said box-like body (320) is constituted by two separate box-like bodies, a first box-like body (320a) being constituted by the bottom (323) provided centrally with a through hole (356), said outer annular wall (324) protruding from said bottom (323), and a second box-like body (320b), which is constituted by a cup which is open upward and is formed by a bottom and by the inner wall (325) on which said tubular portion (328) for connection to said first opening (326) is provided, the lower part of said second body (320b) being inserted with a watertight seal in said through hole (356).

25. The hydraulic pump according to claim 24, characterized in that the upper portions of said inner wall (325) of said second body (320b) are flared upward so as to form an annular support (352) for said impeller assembly (312).

26. The hydraulic pump (10, 100, 200, 300, 400) according to claim

1, characterized in that said box-like body (20) is made of a corrosion- resistant material.

27. The hydraulic pump according to claim 1, characterized in that said box-like body (20, 120, 220, 320, 420) is made of plastic material and/or stainless steel.

28. The hydraulic pump according to claim 1, characterized in that said box-like body (420) is made monolithically of a material that is corrosion-resistant and has high structural strength characteristics.

29. The hydraulic pump according to claim 1, characterized in that said box-like body (420) is made of stainless steel.