DE1548896B2 - FLOW ADJUSTMENT FOR LARGE WATER METER CHECK LEVELS - Google Patents

Description

The invention relates to a flow setting element for large water meter test stands with a discharge side Flow control or shut-off device built into the pipeline, e.g. B. a flap valve.

In the case of water meter test stands, there is a den between the meter to be tested and the comparison vessel Flow-controlling shut-off valve, preferably a throttle valve, built into the pipeline. While in the case of small meters with the low flow rates that occur with them, a sudden shutdown this connection line is not harmful, brings a quick conclusion with large water meters extremely detrimental consequences with itself. So it has happened that too quickly Close water hammers in the pipe network of a municipal utility were caused, leading to the breakage of large Main water pipes led. So it is up to the operation of test stands for large water meters very much on the skill of the person carrying out the test, as this also applies to more precise Measurement must know how to prevent an instantaneous shutoff of the flap valve. With the known The operator must therefore test stands at the time of opening and closing the throttle valve Observe the counter of the meter to be checked very closely, but at the same time it must also observe the in Operate the control element located some distance from the meter. This requires a particularly high level of attention.

The present invention has for its object to avoid these difficulties and a To create adjusting member that the actuation of the valve body largely independent of the Attention of the operator makes and remains constant during the test process Flow and, after the test process, a quick shutdown of the flow, avoiding it Guaranteed from water hammer.

The solution to this problem is seen according to the invention in that the valve shut-off body is connected via an actuating rod with a known, preferably hydraulic actuating cylinder, which is through a between the piston and the cylinder head used bellows two completely separate, on the one hand outside the bellows and below the piston and on the other hand inside the bellows has pressure chambers lying above the piston, the two pressure medium inlet and outlet connections of these are provided in the cylinder head, the one for the closing movement of the valve shut-off body acting as a pressure medium outlet channel with a progressive only shortly before the piston end position effective throttle is provided.

With the help of such an actuating cylinder, the operator can in a simple manner via a The button that can be attached directly to the counter of the test stand can be used to set the exact flow rate as well as trigger the shutdown process. The complete separation of the two pressure rooms by one The bellows prevents the otherwise required leakage during the testing process Sealing points the valve position is changed, whereby the arrangement of both cylinder connections prevents the formation of air bubbles in the cylinder on the cylinder head. This is the for the required constant flow rate is guaranteed. Since during the shutdown process the flow is automatically reduced via the throttle shortly before reaching the final closing position shocks in the pipeline can be prevented despite the fast flap closing movement. These built-in brake is only effective at the last moment of closing, so that a soft, perfect Closing of the valve body is guaranteed.

There are known double-sided actuated control cylinders, the two connecting lines in the Cylinder head are provided. However, these cylinders are not for the actuation of the flow adjustment member intended for large water meter test stands and also not suitable for this because the feed of the pressure medium is carried out downwards via a rigid intermediate jacket pipe, in which the with a seal provided piston is guided, whereby during the test process with time Pressure medium sneak through the seal into the other pressure chamber and thereby the valve position and thus can change the flow rate. In addition, the one for avoiding Pressure surges proposed throttling of the piston end position, which is common to other control cylinders is known.

Appropriately, the throttle consists of a parallel to the actuating rod and with it firmly connected tapered pin, which during the final movement of the actuating rod in the outlet channel penetrates.

Claims (2)

Patent claims: 1. Flow setting element for bulk water meter test stands with a discharge side in the Pipeline built-in flow control or shut-off device, e.g. B. a flap valve, characterized in that the valve shut-off body via an actuating rod (1) with a per se known, preferably hydraulic actuating cylinder (3) is connected, which by a between the piston (4) and the cylinder head (11) inserted bellows (9, 6) two completely separate, . on the one hand outside the bellows and below the piston and on the other hand inside the Bellows above the piston has pressure chambers, the two pressure medium inputs and outlet connections (15, 16) are provided in the cylinder head, the one for the closing movement of the valve shut-off body acting as a pressure medium outlet channel (14) with a first shortly before the piston end position progressively effective throttle (13) is provided. 2. Flow adjusting member according to spoke 1, characterized in that the throttle (13) from a pointed pin lying parallel to the actuating rod (1) and firmly connected to it which penetrates into the outlet channel (14) during the final movement of the actuating rod.