DE1073818B - Control valve, especially for pressure control in hydraulic or pneumatic line systems - Google Patents

Description

GERMAN

The invention relates to control valves, preferably those for pressure control in one hydraulic or pneumatic line system. The aim of the invention is such devices easier and more space-saving to train and to make them independent of temperature and viscosity.

The invention is based on such control valves with one at one end directly to the circuit communicating cylindrical chamber in which a piston slides, which by spring action the Connection between the chamber and a relief line cuts off, the connection can be made by a sliding movement of the piston and the other end of the chamber Connected to the circuit via a first throttle device and provided with the relief line is, and suggests that a second throttle device between the relief line and the dem Piston is arranged opposite end of the chamber.

In the case of valves for regulating the pressure of a medium, one can generally differentiate between the following types:

a) Safety valves that completely close the line system at normal pressure of the medium and open when a certain setting value is exceeded.

b) Pressure control valves, to which the invention also relates, which act progressively and whose degree of opening depends on the actual prevailing Pressure of the medium regulates the flow rate, so that the pressure is constant in this way is kept at a constant value.

Should such valves have high pressures and large amounts of the pressure medium, such as oil or the like., control, then the return springs must be designed very strong and the spring constants so large that there are no significant pressure deviations due to spring deformation. Need such springs lots of space and are also expensive and heavy.

This disadvantage is avoided in the valve according to the invention in that the control of the Valve is made using an additional control system that has only one control system to operate it requires a very small amount of fluid to be controlled in their pressure.

Calculations and tests showed that the two throttle devices with very great accuracy the pressure in the main line can be kept constant, regardless of the viscosity of the print medium. This makes the new device particularly suitable for use on hydraulic systems Systems for plowing.

The invention is explained in detail on the basis of the drawing control valve,

especially for pressure control

in hydraulic or pneumatic

Line systems

Applicant:

Sertec Societe d'Etudes et de Recherches

Techniques,

Paris

Representative:

Dipl.-Ing. RH Bahr and Dipl.-Phys. E. Betzier,
Patent attorneys, Herne, Freiligrathstr. 19th

Claimed priority:
France, 29 August 1956

Gabriel Jean Seguenot, Paris,
has been named as the inventor

Descriptions described which illustrate an example embodiment of the new device.

Fig. 1 shows schemati'sch the arrangement of the essential Elements of a control valve according to the invention;

Fig. 2 is an axial section through an embodiment such a valve.

The device according to the invention consists of a piston I ₁ which is displaceable in a cylinder 2 and which is pressed into its rest position by a spring 6 and thereby closes the opening 5 of a chamber 3 in the cylinder 2, which opens into a relief line 4.

The pressure medium acts directly on the surface 7 of the piston 1 that closes off the chamber 3 and via a first throttle device 8 to the other surface 9 of the piston, one constantly with a second throttle device 11 closes chamber 10 of the cylinder 2 connected. By the throttle device 11 can be used with the help of an automatic or hand-operated control device, the pressure adjust the pressure medium.

If the second throttle device 11 according to FIG. 2 is in a line having a very small diameter 11a is switched on and can therefore be dimensioned correspondingly small, the calculation shows that with some

909710 / S03

Reaching accuracy for a given medium, the pressure p in the chamber 10 of the cylinder 1 depends only on the geometric dimensions of the two throttle devices 8 and 11, i.e. ultimately on the regulation by the throttle device 11 and on the temperature and thus also on the viscosity of the medium is not affected.

The piston is usually in equilibrium when the sum of the pressure p of the medium located in the chamber 10 and acting on the surface 9 and the pressure r of the spring 6 on this surface equals the pressure P of the medium located in the chamber 3 and on is the area 7 acting medium. That means in formulas:

The possibly adjustable and very small value r , for example in the order of magnitude of 2 kg for a limit value of 100 kg / cm ² liquid pressure, is constant, the value p can be regulated by adjusting the second throttle device 11.

If a pressure P is to prevail in circuit A, which represents the main circuit in which the pressure is to be controlled, then it acts

If the pressure in circuit A is above the value P, the pressure difference P - (p - \ - r) on the piston %, whereby this is displaced while releasing at least part of the opening 5 and a new state of equilibrium is achieved by reducing the pressure in circuit A. adjusts

If the pressure in circuit A is below the value P , the pressure difference (p + r) - P on the piston I _{1 is} such that the flow cross-section of the opening 5 is reduced so that the pressure prevailing in circuit A rises to the value P. For this purpose, the second throttle device 11 must be set so that it can only open when the discharge opening 5 is at least partially released. According to Fig. 2, the piston 1 consists of two individual parts, the closure piece 1 α and a sleeve 1 b. The closure piece la has a conical, ground-in part tightly against a rounded seat 12 and a longitudinal recess 13 which opens into an annular chamber 13 a, which corresponds to the chamber 3 of the cylinder 2 and via the opening 5 with the relief line 4 in connection stands when the closure piece la is not resting on its seat 12.

The sleeve 1 b can be displaced in a sleeve 14 which is seated in the cylinder 2 and has wide openings 5 and narrow openings 15. These openings are connected to the relief line 4 or to the throttle devices 8 and 11 via the annular grooves 5 a and 15 a.

In the simplest case, the elastic restoring takes place with the cylinder 2 standing vertically by gravity or by slightly different dimensions of the end faces 7 and 9 of the piston 1 acted upon by the pressure medium.

It is also possible to use a spring 6 which is inserted between the sleeve 1 b and the end wall of the chamber 10.

The throttle device 11 according to FIG. 2 consists of a hollow cylinder 16 which is rotatable about its axis by means of an actuating lever 17 and has _{a wedge-shaped groove 16 0} in the circumferential direction on its outer surface opposite the line junction 11 α , the wider end of which through a radial channel 18 with the interior of the cylinder 2 is in communication. ■ · ■

Claims (3)

Patent claims: 1. Control valve, especially for pressure control in a hydraulic or pneumatic circuit, with a cylindrical one directly connected to the circuit at one end Chamber in which a piston slides which, by spring action, creates the connection between the Chamber and a relief line cuts off, the connection by a sliding movement of the piston and the other end of the chamber via a first Throttle device is connected to the circuit and provided with the relief line, thereby characterized in that a second throttle device (11) between the relief line (4) and the end of the chamber (10) opposite the piston (1) is arranged. 2. Control valve according to claim 1, characterized in that the flow of the second throttle device (11) is adjustable by hand. 3. Control valve according to claim 2, characterized in that the flow rate of the first throttle device (8) is constant. Considered publications:
German Patent No. 400 099;
French Patent No. 1,099,473;
British Patent Nos. 559 788, 589 095;
U.S. Patent No. 2,420,394; 2,447,820,756,771. 1 sheet of drawings © 909 710/303 1.60