Other fittings 9
In last article we got acquainted with a spring safety valve. It is possible to consider such design as the most vserasprostranenny, on the last measure, for introduction in a life. But without considering a spring drive other designs were extended also. Namely, the lever and cargo safety valve completely can meet. The scheme of that device is provided on fig. 1.
Fig. 1. Lever and cargo valve.
The principle of its device is quite simple. There is a lever, which presses on a rod and if to load on the lever a certain weight, we will receive the device which completely will manage to execute function of safety fittings. Thus, in what or it even it is more comfortable, than a design using a spring drive. Matter in that, for regulation of limiting pressure in that design is used the adjusting screw. But its abilities of regulation small. More severe configurations need spring substitution. And here, if the lever and cargo valve is used, it is quite easy to change cargo.
It is easy to calculate the necessary cargo. We have two shoulders of the lever, on fig. 1. they are designated AV and the EXPERT. The shoulder the EXPERT is less than AV shoulder therefore, for ensuring bigger pressure it is possible to use the smallest cargo.
The more the saddle diameter, the is more difficult to provide its density. More precisely, we need bigger cargo and big length of the lever. In previous article we already considered a dvukhsedelny design of safety valves. Clearly, two saddles could promote and in a case with the lever and cargo valve. Only in that design the spring was comfortably entered between saddles, and here, with the lever such assembly any more does not take place in a case. Therefore two levers are used.
Fig. 2. A safety valve with 2 levers.
In this case in one case two settle down in parallel working barrier the mechanism. It is clear that they will be already the smallest diameter. And time so, and cargo on each lever is necessary less, well and the length of levers in this case can be shorter. The device leaves easier and more compactly.
Continuation follows …