GB2117494A

GB2117494A - A valved closure cap

Info

Publication number: GB2117494A
Application number: GB08304040A
Authority: GB
Inventors: Hans Schaal; Wilfried Haag
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1982-03-27
Filing date: 1983-02-14
Publication date: 1983-10-12
Also published as: IT8347770A0; FR2524062A1; DE3211449A1; JPS58172419A; GB8304040D0; IT1164591B; DE3211449C2

Abstract

A closure cap, in particular for a pressurized-liquid circuit of an internal combustion engine, has valves 7, 8 for automatically compensating-out excess, or sub-atmospheric pressures occurring inside the radiator, these valves being mounted in the closure element of a pressure relieving safety valve 6 and acting against spring forces. The closure element of the valve 6 normally seals against the neck 10 of the radiator and serves to protect the cooling system from an excessive rise in pressure, should the relief valve 8 fail. <IMAGE>

Description

SPECIFICATION A closure The invention relates to a circuit closure for a pressurisable liquid circuit of an internal combustion engine.

German Offenlegungsschrift 2,529,189 discloses a closure of the above mentioned type, in which a pressure-relief valve incorporates a resilient valvedisc which, interacting with a helical compression spring, bears against a radiator filler-neck in a manner producing a seal. With this type of closure, however, it has proved disadvantageous that the resilient valve-disc is deformed, and subjected to frictional strain, whenever the closure is operated, as a result of which the leak-tightness of the valve-disc and the responsiveness of the pressure-relief valve are adversely affected.

The invention seeks to provide a closure for a pressurisable liquid circuit in a manner such that the circuit is protected from damage both in the event of small pressure-changes in the region of the pressure-value at which opening of a pressure reliefvalve occurs, and in the event of these pressure-changes becoming large.

According to the invention there is provided a circuit closure for a pressurisable liquid circuit of an internal combustion engine, the closure including valves for automatically compensating excess or sub-atmospheric pressures occurring inside the circuit, these valves being mounted inside the closure and being biassed automatically to a predetermined closed state by spring means, the circuit being closable in a leak-tight manner, by means of a pressure-relief valve, into which a breather valve is integrated, and wherein at least one additional pressure-relieving safety valve is integrated into the closure.

Preferably, the pressure relief valve is integrated within the pressure relieving safety valve. These valves may have different opening pressures, the pressure relieving safety valve preferably opening at a higher opening pressure, typically 1.8 bar, than the pressure relief valve, which may open at 1.1 bar approximately.

The pressure relieving safety valve may have a pot-like shape and the breather valve and the pressure relief valve are located within the overall profile of the pressure relieving safteyvalve.

Two embodiments of the invention will now be described by way of example with reference to the drawing, in which; Figure 1 shows a partial section through a radiator closure, and Figure 2 shows a partial section through a modified form of radiator closure, in the region of the closure-cap.

The radiator closure, represented in Figure 1, incorporates a closure-cap 2, a seal-plate 3, a pot-like housing 4for a conical helical spring 5, and a pressure-relieving safety valve 6 which is designed with a pot-like shape and carries a breather valve 7 and a pressure-relief valve 8. The pressure-relieving safety valve 6 incorporates a peripheral seal 9, which is supported on a bead-like valve-seat 10 of-a filler-neck 26 of a radiator, the latter being omitted from the drawing. The closure may, of course, be incorporated in another part of the working circuit, for example on a header tank. The breather valve 7 comprises a conical helical spring 11, which is supported, on one side, against a valve-plunger 12 and, on the other side, on the base 27 of the pressure-relieving safety valve 6, and a valve-disc 13, provided with a seal 14.The pressu re-relief valve 8 comprises a blanking-cap 16, forming one boundary of a spring-chamber 15, and a cylindrical compression spring 18, this spring exerting a force on a valve-disc 20 which is provided with a seal 19.

Tabs 31 on an outer peripheral zone 30 of the closure-cap 2 engage over a wall-part 32 of the filler-neck which is to be closed. The last turn 33 of the helical spring 5 is supported in a circular recess 28 in the pot-like housing 27 of the pressure relieving safety valve 6.

A liquid-cooling system, in particularforan internal combustion engine, is subjected to a rise in pressure as a result of an increase in the operating temperature of the internal combustion engine.

When the pressure exceeds a first opening-valve, approximating to 1.1 bar, the pressure relief valve 8 opens, so that the coolant flows to the outside via an overflow passage which is known per se, but which is not represented in the drawing.

If a second opening-pressure valve is reached, which approximates to 1.8 bar and can, for example, be reached if the pressure-relief valve 18 is unserviceable, or if the cross-section of the annular gap, formed by the pressure-relief valve 8 in accordance with the pressure conditions, is too small for the coolant which is to escape, the pressure-relieving safety valve 6 opens. The coolant now escapes, likewise via the overflow passage which is known per se, thereby ensuring that the cooling system is not subjected to stressing by an impermissible excess pressure.

As the coolant cools down, the volume of the liquid changes, which causes the pressure in the cooling system to fall. When the pressure has fallen by a defined amount, the breather valve 7 automatically opens and establishes pressure-equilibrium between the cooling system and the surrounding atmosphere.

A radiator-closure 21, partially represented in Figure 2, differs from the radiator-closure 1 represented in Figure 1 merely in that the helical spring 5 is replaced by a diaphragm spring 29.

The closure, according to the invention, incorporates, in a compact design, a pressure-relief valve, a pressure-relieving safety valve, and a breather valve.

In this closure, the pressure-relief valve responds in the event of small pressure-changes in the region of the pressure-value at which opening should occur, while the pressure-relieving safety valve responds in the event of these pressure-changes becoming large, as can result, for example, from a fault in the cooling system, or which can be caused by a faulty pressure-relief valve. At the same time, the pressure at which the pressure-relieving safety valve responds can be set, by design, to a value which is high enough to ensure that its valve-seat bears against the radiator filler-neck with a pressure which guarantees reliable sealing.

Claims

1. Acircuitclosurefora pressurisable liquid circuit of an internal combustion engine, the closure including valves for automatically compensating excess or sub-atmospheric pressures occurring inside the circuit these valves being mounted inside the closure and being biassed automatically to a predetermined closed state by spring means, the circuit being closable in a leak-tight manner, by means of a pressure-relief valve, into which a breather valve is integrated, and wherein at least one additional pressure-relieving safety valve is integrated into the closure.

2. A closure according to Claim 1, wherein the pressure relief valve is integrated within the pressure-relieving safety valve.

3. A closure according to Claims 1 or 2, wherein the pressu re-relief valve and the pressure-relieving safety valve have different opening pressures.

4. A closure according to any one of Claims 1 to 3, wherein the pressure-relieving safety valve opens at a higher opening-pressure than the integrated pressure-relief valve.

5. A closure according to any one of Claims 1 to 4, wherein the pressure-relieving safety valve opens at an opening-pressure of approximately 1.8 bar.

6. A closure according to any one of Claims 1 to 5 the pressu re-relief valve opens at an openingpressure of approximately 1.1. bar.

7. A closure according to any one of Claims 1 to 5, wherein the pressure-relieving safety valve has a pot-like shape, and the breather valve and the pressure-relief valve are located within profile of the pressure-relieving safety valve.

8. A closure according to any one of Claims 1 to 7 wherein the pressure-relieving safety valve functions in conjunction with a spring comprising a helical spring.

9. A closure according to Claim 7 wherein the pressure relieving safety valve functions in conjunction with a spring comprising a diaphragm spring.

10. A closure according to Claim 8 or 9, wherein the said spring is surrounded by a pot-like housing, in which the pressure-relieving safety valve is guided.

11. A circuit closure for a pressurisable liquid circuit of an internal combustion engine substantially as described herein, with reference to and as illustrated in Figure 1 and 2 of the accompanying drawing.