GB2109510A - Valve - Google Patents

Abstract

A valve ball member 4 is held away from a pressure responsive member 3, in the end position shown, by an abutment pin 7, thus permitting flow from an inlet 8 to an outlet 9. Build up of pressure within the valve causes the member 3 to move to the right, the ball 4 moving under the action of a spring 13 to close the valve. A drop in inlet pressure causes the member 3 and hence the ball 4 to return to their initial positions, thus permitting return flow from the outlet. <IMAGE>

Description

SPECIFICATION Pilot-controlled non-return valve The invention relates to a pilot-controlled nonreturn valve useful as a component in hydraulic and pneumatic circuits.

Such valves generally have the task of allowing the fluid to flow in one direction and stopping it from flowing back in the other. The return flow of the fluid is, however, possible under certain conditions.

The state of the art covers without exception pilot-controlled non-return valves in which the closed return flow can be opened through a special plot line. This means that there must always be two independent line systems, namely the actual pressure line and the pilot line.

The disadvantages of such pilot-controlled nonreturn valves are thus not to be seen so much in their operational reliability, but rather in the fact that pilot line connections and channels in the valve itself, as well as additional lines and control elements, result overall in a very high design and control outlay.

Thus, an object of the present invention is to provide a pilot-controlled non-return valve which is characterized by its simple and economical construction to the extent that there is a reduction in the design and control outlay for opening and closing the return flow.

In the valve of the invention, a pilot line for opening and closing the valve with respect to return flow is identical with a pressure line of the valve, a pilot pressure resulting from the differential pressure between the pressure of the fluid on the valve outlet side and the variable pressure of the fluid on the valve inlet side, and the valve block having within it a valve body which, in accordance with the pressure conditions, moves into an end position either opening or closing the return flow.

The advantages of such a construction of pilot controlled non-return valves are the compact design as well as the possibility of a clearly laid out overall circuit.

An embodiment of the present invention is described in greater detail below, with reference to the accompanying drawing, in which Figure 1 shows the valve in its rest/open position, and Figure 2 shows the valve in its working position.

The essential components of the pilotcontrolled non-return valve 1 constituting the illustrated embodiment of the invention are a valve block 2 and disposed therein an axially movable valve body 3 in which is accommodated a closing element 4 in the form of a ball. Attached to a valve cover 5 disposed on the end face of the valve block 2 is a disc 6 which is provided with an opening pin 7 which cooperates under certain conditions with the closing element 4.

The principle of operation is as follows: The fluid flows via the valve inlet side 8 through the valve 1 itself and leaves the latter on the valve outlet side 9 in order there to build up the working pressure. As shown in Fig. 1, it flows first of all through a threaded hole 10 of the valve cover 5 and several small throughflow openings 11 in the disc 6. The fluid also flows through a central bore 12 of the valve body 2. The opening pin 7 forces the closing element 4, against the force of a contact spring 13, out of its seat 14, so that the throughflotv is open since the rear end of the valve body 3 which serves to accommodate the opening pin 7, the contact spring 1 3 and a holding screw 1 5 exhibits appropriate throughflow bores 28 near the seat 14.Passing by the closing element 4, the fluid then reaches a threaded hole 1 6 on the valve outlet side.

As the pressure builds up, there is also an increase in the pressure in a chamber 1 7. The result of this is that the valve body 3, as shown in Figure 2, is forced from a stop face 1 8 of the disc 6 against a stop face 19 9 of the valve block 2. As soon as there is an equalisation of pressure, the closing element 4 comes into contact with its seat 1 4 on the valve body 3, thus preventing the return flow of the fluid (working position).

If the pressure on the valve inlet side is now reduced, e.g. through a pressure pump (not shown), the valve body 3 remains in its position until, disregarding the spring forces mentioned below, the relationship of the pressures between valve inlet side 8 and valve outlet side 9 corresponds to the relationship of the two endface areas 21 and 22 of the valve body 3. If the pressure on the valve inlet side then drops, the valve body 3 moves and comes into contact again with the stop face 18 (Fig. 1). As a result, the closing element 4 is forced out of its seat 1 4 by the opening pin 7, thus opening the valve with respect to return flow.In this connection, a spring 23 supports the movement of the valve body 3 against the stop face 1 8. So that the valve body can assume the rest position shown in Fig. 1, which is, also the open position, it is important for the spring force of spring 23 to be greater than that of the contact spring 1 3.

Various seal rings 24, 25 and 26, which are provided in the valve cover 5, which is fastened by clamping screws 27, as well as in the valve body 3, guarantee the correct functioning of the pilot controlled non-return valve 1 according to the invention.

The invention is not restricted to the embodiment shown in Figs. 1 and 2. On the contrary, it is entirely possible to modify the design possibilities of known pilot-controlied nonreturn valves, taking the present invention as a basis, so as to achieve the same advantages with an identical or equivalent mode of operation.

Parts List 1 Pilot-controlled non-return valve 2 Valve block 3 Valve body 4 Closing element (ball) 5 Valve cover 6 Holding plate 7 Opening pin 8 Valve inlet side 9 Valve outlet side 10 Threaded hole 11 Throughflow opening 12 Central bore 13 Contact spring 14 Seat 1 5 Holding screw 16 Threaded hole 17 Chamber 18 Stop face 19 Stop face 20 Seat 21 Area 22 Area 23 Spring 24 Seal ring 25 Seal ring 26 Seal ring 27 Clamping screws 28 Throughflow bore

Claims (4)

1. Pilot-controlled non-return valve useful as a component in hydraulic and pneumatic circuits, wherein a pilot line for opening and closing the valve with respect to return flow is identical with a pressure line (8, 9) of the valve (1), a pilot pressure resulting from the differential pressure between the pressure of the fluid on the valve outlet side and the variable pressure of the fluid on the valve inlet side, and the valve block (2) having within it a valve body (3) which, in accordance with the pressure conditions, moves into an end position either opening or closing the return flow.

2. Valve according to claim 1, wherein the positioning of the valve body (3) in the open or closed position can be controlled through a pressure pump.

3. Valve according to claim 1 or 2, wherein the valve body (3) in the valve block (2) is so disposed that it can be moved in its longitudinal direction, the direction of movement being essentially determined by the relationship of the end-face areas (21, 22) of the valve body (3) and of the pressures on the valve inlet and outlet sides, and furthermore there is a stationary opening pin (7) which acts in such a way on a closing element (4) accommodated in the valve body (3) that said closing element can be forced out of its position blocking the return flow while the valve body (3) is moved into its corresponding open position.

4. Valve according to claim 1, substantially as described with reference to the accompanying drawing.