NL1003667C2 - Spring-loaded valve for regulating flow of liquid - Google Patents

Abstract

Liquid enters the body (1) of the valve, via a threaded inlet piece (2). A small proportion of the liquid passes by capillary action between the inner wall of the body and the sides of the piston (5). The liquid then flows between the sealing seat (6) on the downstream side of the piston and the outlet nozzle (13). If the downstream pressure is low and the upstream pressure is high, the piston moves downwards, restricting the flow to the outlet. If the reverse is true, the spring (9) pushes the piston upwards, increasing the flow.

Description

-1-

Ventlel just constant flow for liquids.

The invention relates to a valve set of constant flow for liquids at variable supply and back pressures. For a large number of applications where dosing per unit time, the constant yield is a requirement. This applies, inter alia, to disinfection installations, irrigation units and the like.

Constant flow valves are known from 10 publications US-A-4,080,993 and US-A-4,066,096. With these valves, a plunger is pushed over control openings against openings by means of a pressure difference generated by openings.

The problem with these valves is that at high overpressures the valve allows an unregulated flow. Furthermore, rather purely fitting and sliding elements are used, which by friction give a characteristic with hysteresis. These valves are also not suitable for delivering very small amounts of liquid per unit time.

The invention relates to a valve in which the liquid flow in a cylinder flows around a plunger, whereby the pressure difference exerts an axial force on the plunger, so that a discharge opening is closed. A spring exerts an opening force on the plunger. The balance between spring force and plunger force determines the valve output. In this construction, the moving parts do not come into contact with each other. The flow of the liquid is mainly laminar.

The invention includes a variant in which the flow can be controlled electronically, whereby a pressure-independent adjustable flow is realized.

The invention will be explained in more detail with reference to the drawing.

Fig. 1 shows the valve in section.

Fig. 2 shows the valve with a double spring system.

Fig. 3 shows the valve with electronic control.

Fig. 1 shows the valve in the simple design which is installed in a system after being adjusted to the correct flow. The body of the valve is indicated on chain (1). The screw-in part (2) has 1003667.

35 -2- an inlet opening <3). A cylindrical bore (4) is arranged in body (1). In this cylinder (4) is a cylindrical plunger (5). A sealing element (6) in the form of a disc is located at the end of the plunger (5). The flat head side (7) of plunger (5) can form a non-return valve in conjunction with a seal <8>.

Seal <8> is annular and may be in the form of an "O" ring of elastic material. The length of plunger (5) is greater than or equal to the diameter of plunger (5).

There is a spring (9) in cylinder (4). This spring (9) rests on the one hand on a narrowing (10) in cylinder (4) and on the other hand against plunger <5> and presses it against seal (8). Inside the spring (9) is a nozzle (11) with a bore (12). The front of the nozzle (11) is partially chamfered to form an annular sealing surface (13) around bore (12). Nozzle (11) is part 15 of a control element (14). This control element (14) fits into a cylinder (15) and is sealed with a seal (16). Control element (14) can be moved axially by means of a screw thread (17) and can be locked with a locknut (18). Control element (14) includes a bore (19) and an outlet (20) connected to bore (12).

20

The operation is as follows:

The liquid is supplied under pressure through inlet (3). The liquid flows to cylinder (4). Under the influence of the pressure, plunger (5) will be driven against the spring force of spring (9) in the direction of sealing surface (13). Because the liquid must flow through the capillary gap between plunger (5) and cylinder (4), a flow-dependent pressure drop will occur. When the axial force on plunger (5) resulting from the pressure drop is in equilibrium with the spring force, the plunger (5) will occupy a certain position relative to sealing surface (13). A certain amount of liquid will flow through the valve and leave the valve at (20). However, as the supply pressure increases, spring (9) will be pressed more strongly. The passage between sealing surface (13) and sealing (6) will become smaller and the flow resistance will increase. A reduced passage at the sealing surface (13) will thereby cause an increased back pressure and the flow will decrease.

By axially adjusting control element (14), the spring tension of spring (9) will be different when plunger (5) reaches its equilibrium position 1003667.

-3- and then give a modified constant yield.

The choice of spring characteristic, diameter difference between plunger (5) and cylinder (4), the length of plunger (5) and the size of the surface of sealing surface (13) allow the constant flow of the 05 valve to be determined.

In cases where the back pressure becomes too high to give the correct flow, spring (9) will bring plunger (5) against seal (8) and close the passage. The valve al6 check valve acts in this way. If the supply pressure should become impermissibly high, plunger (5) 10 with seal (6) will be pressed against sealing surface (13) and close the discharge. In this way it is not possible for the valve to deliver too much or too little liquid.

In Flg. 2, a variant is indicated in which an inlet (21) is placed transversely. An adjustment member (22) is hereby easily accessible. The counternut (18) is adjusted adjusting means (22). Adjusting member (21) with a seal (23) is axially movable with a screw thread (24). A second spring (25) is placed between adjusting member (22) and plunger (5). In this variant, the yield is regulated by tensioning the second spring (25) more or less. In this way, the valve can be controlled during operation.

In Flg. 3, a variant is shown in which the controlling force is generated against resilience by means of an electromagnet. For this purpose, a coil (26) and a control element (27) and plunger (5) are made of stainless ferromagnetic material. Plunger (5) will be drawn by control element (27) when the coil (26) is energized against the spring force of a spring (28). By modulating the attraction of the electromagnet, the constant flow of the valve can be controlled. It is also possible to pull the sealing surface (13) with an electromagnet plunger (5), whereby a spring provides a counterforce.

In FIG. 1 the position of a coil (29) is indicated by a dotted line. In this variant, the check valve action 35 is therefore retained.

100366 /.

Claims (6)

Valve with virtually constant discharge for liquids with variable supply and / or back pressure, characterized in that in a cylinder (4) there is a plunger (5) with a seal (6) at the head of that plunger <5). the diameter of plunger (5) is so much smaller than the diameter of cylinder (4) that the liquid flow passage between plunger (5) and cylinder (4) forms a capillary with a spring (9) plunger (5) moves in the flow direction whereby the gap 10 between the seal (6) and a nozzle (11) is enlarged, while with increasing release caused by increasing pressure difference between supply and back pressure, the gap between seal (6) and nozzle (11) against the spring action of spring (9) is reduced. Valve according to claim 1, characterized in that by changing the tension of the spring (9), the axial displacement of a control element (14) or the adjustment of a second spring (25) by displacing an adjusting member (22), the virtually constant delivery can be set. 20 Valve according to claim 1 or 2, characterized in that the constant flow can be changed by means of an electromagnet (26, 29), the plunger (5) and the control element (14, 27) of which are made of ferromagnetic material, whereby the actuation of the solenoid coil 25 determines the magnitude of the nearly constant release. Valve according to claim 1, 2 or 3, characterized in that the length of the plunger (5) is greater than or equal to half the diameter of the plunger (5). 30 Valve according to claim 1, 2, 3, or 4, characterized in that the gap between seal (6) and nozzle (11) is completely closed at a maximum permissible pressure difference. Valve according to claim 1, 2, 3, 4, or 5, characterized in that the plunger (5) forms a non-return valve in conjunction with an annular seal (8). 1 00 3 6 6 7.