Liquid product valve assembly for pumps

Abstract

The invention relates to a liquid product valve assembly, intended to be employed in a pump, such as, for example, a pump for spreading paint, solvent, etc. The valve assembly incorporates a valve, provided with a seat, as well as a sealing element, intended to rest on the seat. The valve assembly stands out because the seat includes several support surfaces to support the sealing element, allowing to define different strokes of the sealing element, as a result of which, different pressure drops are defined, allowing the use of liquid products of different densities or viscosities, simply by selecting the corresponding support surface, without the need to increase the number of parts of the valve assembly. The selection of an appropriate pressure drop for each liquid product allows a more uniform delivery of the liquid product.

Description

Technical field and subject matter of the invention

[0001] The present invention can be included in the technological sector of pumps, in particular, but not exclusively, pumps used in conjunction with paint guns. More particularly, the object of the invention relates to a liquid product valve assembly which is applicable to one such pump.Background

[0002] A hydraulic pump is a well-known device that transforms mechanical energy into hydraulic energy. Mechanical energy can be generated by a motor, a pneumatic system, etc. Said mechanical energy, applied to the pump, generates a vacuum action that causes suction of a liquid product contained in a tank and sends it to a hydraulic circuit. The pumps can be classified into centrifugal pumps (hydrodynamic) and hydrostatic pumps (positive displacement). The hydrostatic pumps include reciprocating pumps, which pump a product by reciprocating movement of a piston.

[0003] By means of such reciprocating movement, and in cooperation with two valves, when the piston moves in a first direction, suction of the liquid product is produced from the tank into a first chamber, and from the first chamber into a release chamber. When the piston moves in a second direction, opposite to the first direction, the liquid product escapes from the release chamber into the hydraulic circuit.

[0004] During the time between the movement of the piston in one direction and the opposite direction, there is a pressure drop of the liquid product, because there is still a demand for the product while the product is prevented from accessing the containment chamber until the inlet valve reopens.Summary description of the invention

[0005] The present invention features a liquid product valve assembly, intended to be employed in a pump, such as, for example, a pump for spreading paint, solvent, etc., in accordance with the independent claim. The valve assembly incorporates a valve, provided with a seat, as well as a sealing element, intended to rest on the seat. The valve assembly stands out because the seat includes several support surfaces to support the sealing element, allowing to define different strokes of the sealing element, as a result of which, different pressure drops are defined, allowing the use of liquid products of different densities or viscosities, simply by selecting the corresponding support surface, without the need to increase the number of parts of the valve assembly. The selection of an appropriate pressure drop for each liquid product allows a more uniform delivery of the liquid product where, in particular, for the example of valve assemblies applied to paint pumps, it provides a more consistent painting process and a more uniform result. Other optional features of the invention are described in the dependent claims, as well as in the description of the example embodiment.Brief description of the figures

[0006] The foregoing and other advantages and features will be more fully understood from the following detailed description of exemplary embodiments with reference to the accompanying drawings, to be considered as illustrative and not limitative, in which: Figure 1 shows a simplified schematic side view, longitudinally sectioned, of a cylinder of a paint pump forming part of an example embodiment of the liquid product valve assembly according to the present invention. Figures 2A and 2B show sectional detail views of the cylinder of Figure 1, with the first valve seat providing different support surfaces to the first sealing element. List of references:

[0007] 1Cylinder housing 2Piston 3Support 4Product input 5Containment chamber 6First seat 7Support surfaces 8First sealing element 9Closing position 10Passage position 11Stop 12Valve body 13Release chamber 14Cover 15Opening 16Second seat 17Second sealing element 18Seal 19Stroke Detailed description of an example embodiment

[0008] Next, there follows, with the aid of the foregoing Figures 1-2B, a description in detail of an example of a preferred embodiment of a liquid product valve assembly for a paint pump in accordance with the present invention.

[0009] According to Figure 1, the valve assembly includes a cylinder with a housing (1) which, at a first end, houses a piston (2) longitudinally movable alternately within the housing (1). In the example shown in Figure 1, the piston (2) is vertically movable up and down, according to the double arrow at the top of Figure 1, although the cylinder is not necessarily arranged in a vertical orientation.

[0010] At a second end of the cylinder, opposite to the first end, there is a support (3) with a product inlet (4), which in the example of the figures is coaxial with the housing (1) of the cylinder, to allow entry of the liquid product (in this case, paint) from a tank (not shown) into a containment chamber (5) configured in the support (3), and with which the product inlet (4) is fluidly communicated, as shown by the arrow at the bottom of figure 1.

[0011] In the containment chamber (5), a valve is arranged including a first seat (6), with at least two support surfaces (7), selectable to support a first sealing element (8) intended to seal the containment chamber (5) to prevent the liquid product from flowing back from the containment chamber (5) into the tank. In the embodiment shown in the figures, the first sealing element (8) of the valve is a ball. In other embodiments, it may take other forms, such as conical or truncated cone shape. The first sealing element (8) is movable along the containment chamber (5) between a closing position (9), in which said first sealing element (8) rests on one of the support surfaces (7), preventing the passage of the liquid product, and a passage position (10), in which the first sealing element (8) is separated from the support surface (7), allowing the passage of the liquid product. In the passage position (10), the first sealing element (8) has a movement limited by a stop (11) of the valve, which preferably forms part of a valve body (12), housed in the support (3), for housing the first sealing element (8) and the first seat (6).

[0012] Downstream of the containment chamber (5), there is defined, between the housing (1) and the piston (2), a release chamber (13), fluidly communicated with said containment chamber (5), to allow the passage of the liquid product from the containment chamber (5) to the release chamber (13), as well as from the release chamber (13) to the outside, for example, to a hydraulic circuit of the pump, as indicated by the horizontal arrow in Figure 1. In particular, Figure 1 illustrates that, at the first end of the housing (1), is arranged a cover (14), provided with an opening (15) for letting out the liquid product.

[0013] Similar to that indicated above for the containment chamber (5), in the release chamber (13), a second seat (16) is provided, configured to support a second sealing element (17) intended to seal the release chamber (13) to prevent the liquid product from returning from the release chamber (13) into the containment chamber (5). Similar to what was indicated above for the first sealing element (8), the second sealing element (17) can also be configured in different shapes, such as spherical, conical, truncated conical, etc.

[0014] From the configuration just explained, the operation of the product valve assembly of the invention is defined, by repeated cycling, as follows, with additional help from Figures 2A and 2B: Initially, at a resting moment, the first sealing element (8) is, in the closing position (9), resting on any one of the support surfaces (7) of the first seat (6), closing the entry of liquid product into the containment chamber (5), as well as the second sealing element (17) closes the passage of said liquid product into the release chamber (13). Both containment (5) and release chambers (13) are isolated from each other by a seal (18). When the piston (2) moves along the housing (1) away from the support surface (7), i.e. according to a first movement of the cycle, a vacuum is generated in the containment chamber (5) which causes the first sealing element (8) to move along the cylinder (1), moving away from the support surface (7) up to the stop (11), adopting the passage position (10) and thus allowing the liquid product to enter the containment chamber (5) through the support (3).

[0015] Once the liquid product has accessed the containment chamber (5), the piston (2) moves along the housing (1) in the opposite direction, approaching the support surface (7), in accordance with a second cycle movement, generating pressure in the containment chamber (5). As a consequence, the first sealing element (8) approaches the first seat (6) until it rests on said first seat (6), closing the passage of the liquid product through the support (3), as well as the second sealing element (17) also moves, allowing the passage of the liquid product from the containment chamber (5) to the release chamber (13) and, finally, to the hydraulic circuit, through the opening (15) of the cover (14).

[0016] This entire process is repeated with each cycle of the reciprocating pump.

[0017] In the movement of the piston (2) inside the housing (1), the two first and second movements mentioned above are therefore differentiated, which are detailed below: a) In the first movement, the movement of the piston (2) generates a vacuum in the containment chamber (5), which forces the first sealing element (8) away from the support surface (7) to allow the liquid product to pass. In this first movement, the first sealing element (8) is in contact with the stop (11) at the passage position (10), which is further with respect to the product inlet (4), i.e., downstream. b) According to the second movement, the movement of the piston (2) in the opposite direction causes the first sealing element (8), under the effect of pressure, to close on the first seat (6), preventing the liquid product from returning from the containment chamber (5) to the tank through the product inlet (4). In this second movement, the sealing element (8) is in contact with the support surface (7), in the closing position (9), closer than the passage position (10), with respect to the product inlet (4), i.e., upstream.

[0018] According to the above, when the first sealing element (8) is in the closing position (9), supported on one selected of the support surfaces (7), the return of the liquid product from the containment chamber (5) through the product inlet (4) is prevented, whereas, when the first sealing element (8) is in the passage position (10), away from the selected support surface (7), the liquid product is allowed to pass into the containment chamber (5) through the support (3), namely through the product inlet (4).

[0019] During the movement of the first sealing element (8) between the passage position (10) and the closing position (9) described in a) and b) above, there is a pressure drop in the liquid product, because there is still a demand for the liquid product, but the feed is stopped until the first sealing element (8) makes a stroke (19) from the passage position (10) to the closing position (9).

[0020] By means of the product valve assembly for paint pumps, according to the present invention, and without the need to increase the number of components, the stroke (19) is modified. For denser products, a longer stroke (19) would be required and therefore more closing time, whereas, with less dense products, the stroke (19) and therefore the closing time, could be shorter. This allows the valve assembly to be adapted to the type of liquid product being used. The objective is to get the first sealing element (8) to close as soon as possible, but allowing enough liquid product to pass through to achieve a lower pressure drop in the liquid product and a more constant painting process. By using a valve assembly with two different strokes (19), it is possible to use liquid products with different densities or viscosities without the need to use different parts, just change their position. Figures 2A and 2B each show the use of one of the support surfaces (7), where the passage position (10) of the first sealing element (8) and the closing position (9) of the first sealing element (8) can be seen in full lines. Figure 2B shows a stroke (19) smaller than figure 2A.

[0021] The above is achieved by providing the first seat (6) with the plurality of support surfaces (7) described above, each of which is configured so that, with respect to the stop (11), which defines the passage position (10), a different value of the stroke (19) occurs, as best seen in Figures 2A and 2B. In this way, using the same parts, and only changing the support surfaces (7), the effect described above is achieved. According to a more preferable example, there are two support surfaces (7), preferably located on opposite faces of the first seat (6), said first seat (6) being removable, to be mounted selectively offering one of the two support surfaces (7), so that it would only be necessary to remove the first seat (6), and reinstall it in opposite orientation, to be able to alternate the use of the pump between a liquid product of higher or lower density.

Claims

1. Liquid product valve assembly for pumps, comprising a valve with: - a first seat (6), with at least one support surface (7); - a first sealing element (8), movable between a closing position (9), in which the first sealing element (8) rests on the support surface (7), preventing the passage of the liquid product, and a passage position (10), in which the first sealing element (8) is separated from the support surface (7) to allow the passage of the liquid product; and - a stop (11) to limit the movement of the first sealing element (8), defining the passage position (10); characterized in that the first seat (6) comprises two support surfaces (7), wherein the support surfaces (7) are configured so as to define respective closing positions (9) associated with different strokes (19) of the first sealing element (8) from the passage position (10) towards the closing position (9), wherein the two support surfaces (7) are located on respective opposite faces of the first seat (6), said first seat (6) being removable to be mounted by selectively offering one of the two support surfaces (7).

2. Liquid product valve assembly for pumps, according to claim 1, wherein the first sealing element (8) has a ball shape, conical shape or truncated cone shape.

3. Liquid product valve assembly for pumps, according to any one of claims 1-2, further comprising: - a cylinder, provided with a housing (1) with a first end, and a second end opposite to the first end; - a support (3), at the second end of the housing (1); - a containment chamber (5), configured in the support (3), for receiving the liquid product, through a product inlet (4) of the support (3) which is fluidly communicated with the product inlet (4); wherein the valve is located in the containment chamber (5), being the housing (1), the support (3), the containment chamber (5), the first seat (6) and the first sealing element (8) configured such that, when the first sealing element (8) is in the closing position (9), supported on a selected one of the support surfaces (7), the return of the liquid product from the containment chamber (5) through the product inlet (4) is prevented, whereas, when the first sealing element (8) is in the passage position (10), away from the selected support surface (7), the liquid product is allowed to pass into the containment chamber (5) through the product inlet (4).

4. Liquid product valve assembly for pumps, according to claim 3, additionally including a piston (2), housed at the first end of the housing (1), and longitudinally movable alternatively within the housing (1), with the piston (2), the first seat (6), the containment chamber (5), and the first sealing element (8) configured so that a first movement of the piston (2) in the direction of moving away from the support surface (7) generates a vacuum in the containment chamber (5) causing the first sealing element (8) to move along the housing (1), moving away from the support surface (7) until it reaches the stop (11), allowing the entry of the liquid product into the containment chamber (5) through the product inlet (4) of the support (3); whereas, once the liquid product has entered the containment chamber (5), a second movement of the piston (2) approaching the support surface (7) generates a pressure in the containment chamber (5) by which the first sealing element (8) approaches the first seat (6) until it rests on the support surface (7), preventing the passage of the liquid product through the product inlet (4) of the support (3).

5. Liquid product valve assembly for pumps, according to any one of claims 1-4, which additionally includes a valve body of which the stop (11) forms part.

6. Liquid product valve assembly for pumps, according to claims 3 and 5 simultaneously, wherein the valve body (12) is housed in the support (3).

7. Liquid product valve assembly for pumps, according to any of the claims 1-6, which additionally incorporates, downstream of the containment chamber (5), and defined in the cylinder, between the housing (1) and the piston (2), a release chamber (13), fluidly communicated with the containment chamber (5) to allow the passage of the liquid product from the containment chamber (5) to the release chamber (13), as well as from the release chamber (13) to the outside.

8. Liquid product valve assembly for pumps, according to claim 7, wherein the release chamber (13) has a second seat (16), configured to support a second sealing element (17) intended to seal the release chamber (13) to prevent the liquid product from flowing back from the release chamber (13) into the containment chamber (5).

9. Liquid product valve assembly for pumps, according to claims 4 and 8 simultaneously, wherein the containment chamber (5), the piston (2), the second sealing element (17) and the release chamber (13) are configured so that the pressure generated in the containment chamber (5) by the second movement of the piston (2) additionally generates that the second sealing element (17) also moves, allowing the passage of the liquid product from the containment chamber (5) to the release chamber (13) and to the outside.

10. Pump including the valve assembly described in any one of claims 1-9.

11. Pump, according to claim 10, further comprising a hydraulic circuit, fluidly connected with the release chamber (13) downstream of said release chamber (13) to dislodge the liquid product.

12. Pump, according to any of claims 10-11, characterized in that it is a paint pump.

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