High pressure piston displacement pump

Abstract

The invention relates to a piston volumetric pump comprising: a cylinder head provided with an inlet manifold and a delivery manifold of fluid and a seat for housing a delivery valve; a cylinder sleeve in which a reciprocating piston slides, the cylinder sleeve defining with the cylinder a compression chamber; a delivery valve comprising a valve body having an intermediate portion housed in the valve seat and a first portion fitted inside the cylinder sleeve; a high pressure gasket placed between the first portion of the valve body and the inside of the cylinder sleeve, and a low pressure gasket located between the cylinder head and the cylinder sleeve outside the valve seat; a supply chamber for supplying a low pressure fluid is defined by at least the outer surface of the side wall of the intermediate portion of the valve body, at least the inner surface of the first cavity, and the surface of the cylinder sleeve, the supply chamber being in communication with an inlet duct of low pressure fluid and the inlet manifold.

Description

Technical Field

[0001] This invention relates to the field of piston positive displacement pumps, which can be installed on high-pressure cleaners or other machines for distributing and / or delivering fluids at high pressures, for example, about 1500 bar. Background Technology

[0002] Piston positive displacement pumps typically include an inlet manifold, a delivery manifold, and a regulating valve. The inlet manifold is adapted to connect to a tank containing the fluid to be pumped (typically water). The delivery manifold is adapted to connect to a fluid distribution device (e.g., a spray gun or distribution nozzle) equipped with terminal nozzles. The regulating valve is hydraulically positioned between the delivery manifold and the distribution device and is designed to regulate the maximum delivery pressure of the fluid.

[0003] Additionally, a piston positive displacement pump typically includes a pump housing defining one or more cylinders and a cylinder head attached to the pump housing and closing one end of each cylinder. A reciprocating piston is slidably housed within each cylinder, and the piston, together with the corresponding cylinder and cylinder head, defines a corresponding variable-volume compression chamber. The pistons are kinetically connected to a drive shaft (eccentrically) via a respective connecting rod-crank mechanism designed to convert the rotational motion of the drive shaft, provided by a drive motor, into the linear reciprocating motion of the piston.

[0004] Each compression chamber is connected to the inlet manifold via its own inlet check valve and to the outlet manifold via its own delivery check valve.

[0005] High pressure is ensured for the fluid delivered by the end nozzle through a fluid sealing system on the piston and materials used to ensure the sealing system is sufficiently durable.

[0006] For each piston, the known sealing system consists of a high-pressure gasket of harder material placed between the cylinder and the delivery valve body, and a low-pressure gasket of softer material placed between each cylinder and the pump cover.

[0007] Dual-gasket systems are not particularly effective because when the high-pressure gasket wears down due to high pulsating loads, it often causes high-pressure fluid leakage, which in turn quickly wears down the low-pressure gasket, causing fluid leakage out of the pump housing. Summary of the Invention

[0008] The purpose of this invention is to overcome the aforementioned disadvantages of the prior art within the scope of a simple and reasonable solution and at a controllable cost.

[0009] These objectives are achieved through the features of the invention as set forth in the independent claims. The dependent claims summarize the preferred and / or particularly advantageous aspects of the invention.

[0010] One embodiment of the present invention provides a piston positive displacement pump, comprising:

[0011] - The cylinder head, which is equipped with a fluid inlet manifold and a fluid delivery manifold.

[0012] - Cylinder liner, in which a reciprocating piston slides, the cylinder liner together with the cylinder defines the compression chamber.

[0013] - The cylinder head includes a seat for receiving a delivery valve, the seat including at least a first cavity, preferably having a circular cross-section, the first cavity having an opening on the cylinder head surface in contact with the cylinder liner.

[0014] The delivery valve includes a valve body having a central portion received in the first cavity and a first portion fitted within a cylinder liner.

[0015] The valve body has a high-pressure fluid delivery conduit and at least one low-pressure fluid inlet conduit, the inlet conduit having an opening at the compression chamber and an opening on the side wall leading to the intermediate portion.

[0016] - A high-pressure gasket, placed between the first part of the valve body and the interior of the cylinder liner, and a low-pressure gasket, located outside the first cavity between the cylinder head and the cylinder liner.

[0017] - A supply chamber for supplying low-pressure fluid is defined by the outer surface of the sidewall of at least the middle portion of the valve body, the inner surface of at least the first cavity, and the surface of the cylinder liner. The supply chamber is in communication with the inlet pipe and inlet manifold for the low-pressure fluid.

[0018] Thanks to this solution, fluid flow from the high-pressure gasket flows into the low-pressure fluid supply chamber, reducing wear on the low-pressure gasket and thus increasing its lifespan (and consequently reducing the need for maintenance work to replace the second gasket).

[0019] One aspect of the invention provides that the sidewall of the middle portion of the valve body of the delivery valve has an annular groove to increase the volume of the supply chamber.

[0020] This solution reduces the pressure inside the supply chamber by facilitating the flow of fluid from the high-pressure gasket into the supply chamber.

[0021] One aspect of the invention provides a valve body having a second portion, the free end of which includes a valve seat, on which a baffle acts.

[0022] Another aspect of the invention is that the second portion is accommodated in a second cavity, which preferably has a circular cross-section, and the second cavity originates from the rear wall of the first cavity and is coaxial with the first cavity.

[0023] Another aspect of the invention is to insert the cylinder liner into the outer casing.

[0024] Another aspect of the invention provides a cylinder head fixed to a housing.

[0025] These aspects of the invention ensure that the pump has greater mechanical robustness.

[0026] Another aspect of the invention provides a low-pressure fluid inlet valve associated with a cylinder.

[0027] Combining the inlet valve with the cylinder makes the pump more compact.

[0028] According to another embodiment of the invention, the inlet valve includes a baffle having an annular shape to block the opening of the inlet pipe and having a central hole at the delivery pipe.

[0029] The annular shape of the conveying baffle has the advantage of making the baffle and thus the inlet valve compact, and it also allows the inlet pipe to be arranged circumferentially to the central conveying pipe, which also makes the valve body of the conveying valve compact.

[0030] Another aspect of the invention provides that the positive displacement pump includes a housing integral with an outer casing, and a thrust crank mechanism associated with a piston is housed within the housing.

[0031] This solution allows for more efficient pump implementation while maintaining the separation of the lubricating oil in the thrust crank mechanism from the fluid pumped by the pump.

[0032] Another aspect of the present invention is provided that the volumetric pump includes a plurality of cylinders, each of which houses a reciprocating piston.

[0033] This aspect of the invention makes it possible to manufacture pumps with different fluid flow rates. Attached Figure Description

[0034] Further features and advantages of the invention will become more apparent with the aid of the accompanying drawings, and after reading the following description provided by way of non-limiting example.

[0035] Figure 1 This is a cross-sectional view of an embodiment of a piston-displacement pump formed in a plane including the piston axis.

[0036] Figure 2 It is along Figure 1 Sectional view of the cross-sectional trajectory II-II.

[0037] Figure 3 yes Figure 1 A magnified view of a portion of it.

[0038] Figure 4 yes Figure 1 Another enlarged view of a portion. Detailed Implementation

[0039] With particular reference to these accompanying drawings, the piston-volume pump that delivers fluid (typically water at high pressure, i.e., about 1500 bar and above) is generally marked as 10.

[0040] The positive displacement pump 10 has a housing 20, inside which a cylinder liner 30 is housed, the cylinder liner 30 containing a cylinder 35, wherein at least one piston 4 slides within the cylinder 35, the piston 40 reciprocating thanks to a thrust crank mechanism associated with the piston itself.

[0041] The cylinder 35 can be housed within the cylinder liner 30 such that its axis A is parallel to or preferably coincides with the axis of the cylinder liner 30 itself.

[0042] The cylinder liner 30 includes a first axial end portion 36, which may be defined by a flat surface orthogonally oriented relative to the axis of the cylinder 35.

[0043] The first axial end 36 of the cylinder liner 30 is closed by the cylinder head 50, in which at least one low-pressure fluid inlet manifold 60 and at least one low-pressure fluid delivery manifold 70 are obtained. Figure 2 The low-pressure sealing gasket 55 is placed between the cylinder head 50 and the cylinder liner 30. The low-pressure sealing gasket 55 may have an annular shape with its axis parallel or coincident with the axis A of the cylinder 35, and the low-pressure sealing gasket 55 may be accommodated in a valve seat 56 obtained on the surface of the axial end 36.

[0044] In the illustrated embodiment, as an example, the axial end 25 of the housing 20 is coplanar with the axial end 36 of the cylinder liner 30, and the cylinder head 50 abuts against the two axial ends 25 and 36 and is integrally formed with the housing 20 by conventional fixing screws (not shown).

[0045] The reciprocating piston 40, together with the corresponding cylinder 35 and cylinder head 50, defines their respective variable volume compression chambers 99.

[0046] exist Figure 2 In the illustrated embodiment, the volumetric pump 10 includes a plurality of identical cylinders 35 within the housing 20, in this case three, spaced apart from each other and parallel to each other, wherein each piston 40 slides within the cylinder. This does not preclude other embodiments of the invention from including a different number of cylinders.

[0047] The cylinder head 50 has a seat 90 at the cylinder 35 for accommodating a pressure fluid delivery valve 100, which includes a valve body 110 and a baffle 111 acting on a valve seat 112 of the valve body 110.

[0048] The seat 90 has at least one first cavity 95 having a circular cross-section (e.g., cylindrical) whose axis is parallel to or coincides with the axis A of the cylinder 35 and / or the cylinder liner 30.

[0049] Special Reference Figure 3 The first cavity 95 has an opening 96 on the contact surface between the cylinder head 50 and the first axial end 36 of the cylinder liner 30.

[0050] The diameter of the opening 96 is smaller than the outer diameter of the cylinder liner 30, such that there is a seat 56 for accommodating the low-pressure gasket 55 between the diameter of the first cavity 95 at the opening 96 and the outer diameter of the cylinder liner 30. Figure 3 and 4 As shown in the image.

[0051] The valve body 110 of the delivery valve 100 includes a first part 120 and an intermediate part 115. The first part 120 is fitted into the cylinder liner 30 by the insertion of a high-pressure gasket 130, and the intermediate part 115 is accommodated in a first cavity 95.

[0052] In the example shown, the first part 120 has two annular bands 121 and 122, wherein the first annular band 121 serves as a seat for the sealing gasket 130, and the function of the second annular band 122 located at the free axial end of the first part 120 will be explained below.

[0053] The valve body 110 has a high-pressure fluid delivery pipe 140 and at least one low-pressure fluid inlet pipe 150, wherein the high-pressure fluid delivery pipe 140 is preferably coaxial with the longitudinal axis A of the cylinder 35.

[0054] The inlet pipe 150 has an opening 151 at the compression chamber 99 and an opening 152 in the side wall 116 leading to the middle portion 115 of the valve body 110.

[0055] In the illustrated embodiment, as an example, the first opening 151 is located on the surface of the free end of the first portion 120 of the valve body 110 at the compression chamber 99.

[0056] In the illustrated embodiment, the valve body has eight low-pressure fluid inlet pipes 150 that are equidistant from each other at equal angles, and are visible in pairs in the figures.

[0057] The maximum outer diameter of the middle portion 115 of the valve body 110 is greater than the inner diameter of the cylinder liner 30 and smaller than the diameter of the first cavity 95, such that the low-pressure fluid supply chamber 160 is defined at least by the sidewall 116 of the middle portion 115 of the valve body 110, a portion of the inner surface of the first cavity 95, and a portion of the surface of the axial end 36 of the cylinder liner 30, the supply chamber 160 communicating with each low-pressure fluid inlet pipe 150 and fluid inlet manifold 60.

[0058] Therefore, the high-pressure fluid flowing from the high-pressure gasket 130 into the low-pressure fluid supply chamber 160 reduces wear on the low-pressure gasket 55, thereby increasing its service life. This makes it possible to reduce the maintenance work required to restore the low-pressure gasket 55.

[0059] In the illustrated example, at least one annular groove 127 is formed on the outer surface of the sidewall 116 of the middle portion 115 of the valve body 110 to increase the volume of the supply chamber 160.

[0060] In the illustrated embodiment, the seat 90 includes a second cavity 97 coaxial with the first cavity 95 and originating from the rear wall of the first cavity 95 opposite to the opening 96, which accommodates the second portion 118 of the valve body 110.

[0061] The second part 118 is far from the first part 120 and opposite to the first part 120.

[0062] In the illustrated embodiments ( Figure 3 The free end of the second part 118 includes a valve seat 112, on which a baffle 111 of the delivery valve 100 acts. Specifically, the baffle 111 is accommodated within a support retainer 113 and is adapted to translate within the support retainer 113, which is inserted into an annular groove at the free end of the second part 118 of the valve body 110. A high-pressure gasket 119 of a common type is placed between the retainer and the wall of the groove.

[0063] The baffle 111 is typically held against the valve seat 112 by a compression spring 114 inserted in the retainer 113.

[0064] As can be seen from the accompanying drawings, cylinder 35 is associated with a low-pressure fluid inlet valve 80, which includes a baffle 81 for blocking the opening 151 of the inlet pipe 150. The baffle 81 is annular and has a central hole at the delivery pipe 140.

[0065] In particular, in the illustrated embodiment, the cylinder 35 has two opposing axial ends, which are shaped like shank feet 38 and 39.

[0066] The outer diameter of the stem 38 associated with the inlet valve 80 is smaller than the maximum outer diameter of the cylinder, and it is provided with four through holes 380, which are equidistant from each other at an angle, for fluid to enter the chamber 100. The inlet valve 80 is inserted in the annular space between the outer surface of the stem 38 and the inner surface of the cylinder liner 30.

[0067] In detail, the inlet valve 80 includes a cup-shaped body 82 ( Figure 4The cup-shaped body 82 is inserted into the handle 38 and has a hole in the bottom wall for the handle 38 to pass through. The open end of the cup-shaped body 82 is received in the annular space defined between the inner surface of the cylinder liner 30 and the annular band 122 of the first part 120 of the valve body 110, and has the function of holding the high pressure gasket 130 in place.

[0068] A compression spring 83 is inserted between the handle foot 38 and the side surface of the cup-shaped body 82, and the baffle 81 is restrained by the compression spring, so the baffle 81 is normally kept in the closed position, i.e., against the opening 151 of the delivery pipe 150.

[0069] On the other hand, the handle 39 of cylinder 35 ( Figure 4 The piston 40 bushing 180 is inserted into the perforated cavity 300 of the cylinder liner 30, and the piston 40 bushing 180 is accommodated in the perforated cavity. The sealing gasket 181 is placed between the bushing 180 and the foot 39.

[0070] The outer casing 20 has a second axial end 26, and a crankcase 27 is fixed to the second axial end 26. The crankcase 27 is closed at the other end by a cover 28. The crankcase 27 houses a crankshaft 200 and three connecting rods 220, each of which is hinged to the crankshaft 200 and fixed to a rear axle 230 on a corresponding piston 40, thus forming a thrust crank mechanism (connecting rod crank type) adapted to convert the rotational motion of the crankshaft 200 into the reciprocating motion of the piston 40 in the direction defined by its longitudinal axis A.

[0071] The rotation of the crankshaft 200 is driven by a motor (not shown) located outside the crankcase.

[0072] Between the crankcase 27 and the cylinder liner 30 is a perforated clamp 240 that allows the piston to pass through. The clamp 240 has a seat for receiving a lip gasket 250, which prevents any water from leaking from the high-pressure gasket 181.

[0073] This invention, conceived in this way, is easily subject to several modifications and variations, all of which fall within the scope of the inventive concept. Furthermore, all details can be replaced by other technically equivalent elements.

[0074] In practice, the materials used, as well as the accompanying shapes and sizes, can be arbitrary as needed without deviating from the scope of protection of the appended claims.

Claims

1. A piston positive displacement pump (10), comprising: - Cylinder head (50), which is provided with fluid inlet manifold (60) and delivery manifold (70). - Cylinder liner (30), in which a reciprocating piston (40) slides, the cylinder liner (30) together with the cylinder (35) defining a compression chamber (99). - The cylinder head (50) includes a seat (90) for receiving a delivery valve (100), the seat (90) including at least one first cavity (95) having an opening (96) on the cylinder head surface (50) in contact with the cylinder liner (30). - The delivery valve (100) includes a valve body (110) having an intermediate portion (115) received in the first cavity (95) and a first portion (120) fitted into the cylinder liner (30). - The valve body (110) has a high-pressure fluid delivery pipe (140) and at least one low-pressure fluid inlet pipe (150), the at least one low-pressure fluid inlet pipe (150) having an opening (151) at the compression chamber (99) and an opening (152) leading to the side wall (116) of the intermediate portion (115). - A high-pressure gasket (130) is placed between the first portion (120) of the valve body (110) and the interior of the cylinder liner (30); - A supply chamber (160) for supplying low-pressure fluid, the supply chamber (160) communicating with the inlet pipe (150) for the low-pressure fluid and with the inlet manifold (60), the supply chamber (160) being defined by the outer surface of the sidewall (116) of at least the intermediate portion (115) of the valve body (110) and by the inner surface of at least the first cavity (95). The feature is that the supply chamber (160) is further defined by the surface of the cylinder liner (30), and wherein the low-pressure gasket (55) is outside the first cavity (95) and located between the cylinder head (50) and the cylinder liner (30).

2. The positive displacement pump (10) according to claim 1, characterized in that, The sidewall (116) of the middle portion (115) has an annular groove (127) to increase the volume of the supply chamber (160).

3. The positive displacement pump (10) according to claim 1, characterized in that, The valve body (110) has a second portion (118), the free end of which includes the valve seat (112) of the delivery valve (100), wherein a baffle (111) acts on the valve seat.

4. The positive displacement pump (10) according to claim 3, characterized in that, The second part (118) is housed in a second cavity (97), which begins at the bottom wall before the first cavity (95) and is coaxial with the first cavity (95).

5. The positive displacement pump (10) according to claim 1, characterized in that, The cylinder liner (30) is assembled inside the outer casing (20).

6. The positive displacement pump (10) according to claim 5, characterized in that, The cylinder head (50) is fixed to the outer casing (20).

7. The positive displacement pump (10) according to claim 1, characterized in that, The volumetric pump (10) includes an inlet valve (80) for low-pressure fluid associated with the cylinder (35).

8. The positive displacement pump according to claim 7, characterized in that, The inlet valve (80) includes a baffle (81) having an annular shape to block the opening (151) of the inlet pipe (150) and a central hole at the delivery pipe (140).

9. The positive displacement pump (10) according to claim 5, characterized in that, Includes a crankcase (27) integral with the outer casing (20), in which a crank system associated with the piston (40) is housed.

10. The positive displacement pump (10) according to claim 1, characterized in that, The volumetric pump (10) includes a plurality of cylinders, each containing a reciprocating piston (40).

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