DE102007031652A1 - Pressure relief valve has flexible elastomer membrane fixed to base of valve plate which has characteristics of spring membrane - Google Patents

Abstract

The pressure relief valve has a flexible elastomer membrane (13) fixed to the base of the valve plate (19). This has the characteristics of a spring membrane.

Description

Technical area

The The invention relates to a valve, in particular pressure relief valve, for a fluid.

State of the art

From the DE 15 50 614 is a closing member for pneumatic check valves known. This closing member is made of an elastic material and is a stiffened valve plate, which has a sealing ring or foot ring and consists of several, the ring and the valve plate connecting, conically or cylindrically arranged buckling springs forming webs. A disadvantage of such a closing member is the fact that the webs must have a defined weakening and due to the material properties is not guaranteed that a uniform and reliable sealing of the valve is ensured by the spring bars.

According to the general known prior art pressure relief valves with a Combination of sealing diaphragm and compression spring leads out. These Combination has the disadvantage that the spring has a constant characteristic owns and so that the pressure can not be reduced quickly, there when opening the compression spring the spring characteristic increases further.

on the other hand So-called safety mats are known, for example, with remote controls in TV sets or DVD players and also under the name 'Silicon Rubber Key Pads' as switching elements be used. These have the property when pressed first one build up a certain back pressure. When operated beyond a certain stroke, leaves the Counterpressure but noticeably after, and it turns a kind of snap effect one. Valve functions do not feature such key pads.

The On the one hand, the invention aims to provide a valve which works reliably and ensures a reliable seal and on the other hand - at the increase in overpressure over certain extent - a quick opening allows.

Disclosure of the invention

Of the essential advantage of the invention is that the Überdruckven til leaps open and thus referring to the opening pressure and the opening cross-section reliable can be set. The use of a dish plate or an elastic plate is particularly economical, because no additional elements such as spring or valve seal needed become.

According to one Embodiment of the invention, the elastic plate is an elastomeric material and forms a unit with the valve plate.

Of the elastic plate has according to a Another embodiment of the invention at the edge of a mounting flange up, over a connecting piece and cover is fixed. The lid can weiterbildungsgemäß on the Connecting piece via locking elements be connected, this means that only a clipping of the Cover is required after inserting the valve plate. The Manufacturing costs are considerably reduced by this simple assembly.

A further advantageous embodiment of the invention is that depending on the shape of the valve disk, a different opening course possible is. For draining the fluid, due to the overpressure through the valve flows, can an opening be arranged on the mounting flange.

These and other features are not only in the claims but Also to be taken from the description and the drawings.

Brief description of the drawings

It shows:

1 In a sectional view, a pressure relief valve in the closed position,

2 in a sectional view of the pressure relief valve in an open position,

3 the comparison of the spring characteristics of a compression spring and a in 1 illustrated overpressure membrane.

Embodiment (s) the invention

This in 1 illustrated pressure relief valve 10 is on a pipe 11 arranged. This tube is used for example in the crankcase ventilation of an internal combustion engine, ie, through this tube flows the crankcase gas, which is returned to the internal combustion engine. In the discharge of crankcase gas, it is necessary that this does not exceed a certain overpressure value in the pipeline. As soon as this overpressure value is exceeded, this overpressure must be reduced very quickly via a suitable valve. This is possible with the valve shown.

On the pipe 11 is a valve stub 12 arranged, which is concentrically designed and an An bearing surface for a valve disk 13 forms. On the tube is also a mounting flange 14 arranged concentric with the valve stub 12 runs.

The mounting flange is covered by a lid 15 completed. This lid has circumferentially arranged snap elements 16 that is in a groove 17 on the mounting flange 14 engage. The seal between the lid 15 and mounting flange 14 takes place over the sealing edge 18 the valve plate 19 ,

The valve plate 19 itself is in the middle area with the valve plate 13 provided and - as already mentioned - at the edge with the sealing edge 18 , It consists of an elastomeric material, which ensures due to its elasticity that in the state shown here, the valve disk 13 sealing on the valve neck 12 rests and the crankcase gas, the according to the arrows 20 . 21 through the pipe 11 flows, can not escape. This means that the valve plate 19 is biased and such that the middle, resilient area 22 which is closed at all times, a force according to the arrow 23 on the valve plate exercises.

If the pressure in the pipe increases 11 on, according to 2 (Same parts are provided with the same reference numerals) the valve disk 13 from the valve spigot 12 lifted. This occurs abruptly due to the snap action of the valve plate. This is a relatively large opening cross-section for the reduction of the pressure in the pipe 11 Approved. After reaching the set maximum permissible overpressure, the valve disk becomes the valve stub 12 close again.

In 3 is the spring characteristic B of the valve plate 19 shown in comparison to the spring characteristic A of a compression spring. The switching path "s" is shown on the x-axis, the actuating force "p" on the y-axis.

A normal compression spring has the property that it is analogous to the actuation force executes a switching path, this shows the characteristic a.

Characteristic b shows the characteristic curve of the valve plate 19 , It can be seen that the switching path is initially very ge ring up to a certain operating force. Subsequently, with a further increasing operating force, ie a further increase in pressure, the jump effect occurs and the REQUIRED operating force decreases abruptly. Only after a further covered switching path increases this again. This effect makes use of the device to an extreme overpressure in the pipe 11 to avoid.

Of the main advantage is that to keep open the once open Check valve plate across from the initial opening power only a significantly reduced air energy is required. Here through is also the throttle effect of the check valve considerably ge lowers.

Claims (6)

Valve, in particular overpressure valve, for a fluid, with a housing, which an opening has and this opening is closed with a valve plate, wherein the valve plate is arranged on an elastic plate and this plate on the outer edge on a housing fixed Structure is attached, wherein the elastic plate has a spring characteristic has, which shows a jumping diaphragm course. Valve according to claim 1, characterized in that the elastic plate is made of an elastomeric material and with the valve plate is a unit. Valve according to claim 1, characterized in that the elastic plate a running on the edge mounting flange has, which rests against a connection piece and with a lid is fixed. Valve according to claim 3, characterized in that the lid is connected to the connecting piece via locking elements is. Valve according to one of the preceding claims, characterized characterized in that the jumping membrane up to a certain pressure increase exercises a counterforce and the opposing force over a certain pressure over 50% reduced. Valve according to one of the preceding claims, characterized characterized in that the mounting flange has an opening for Derive the overpressure the housing having.