5.5.3. Repair of a pneumatic actuator of a butterfly valve

 PERFORMANCE ORDER

Having hooked a pricker, we remove a lock ring of draft of a pneumatic actuator of a butterfly valve of the second camera.

By the crosswise screw-driver it is turned off two screws of fastening of the case of a pneumatic actuator...

… we remove it and laying.

We check serviceability of a diaphragm of a pneumatic actuator or we replace it by analogy with the starting arrangement.

Having pressed on a diaphragm rod, we close a finger an entrance opening.

At a serviceable pneumatic actuator the rod completely will return to a starting position only after opening of an entrance opening.
We do not recommend to disassemble the pneumatic actuator case needlessly as it is necessary to select draft length by practical consideration.
If the diaphragm mechanism of a pneumatic actuator of the second gate was disassembled – we regulate length of its draft:

we weaken a lock-nut on draft...

… also we regulate its length that at completely closed butterfly valve of the second camera the opening of draft was opposite to a finger of the intermediate lever.

We put on a rod a finger and we fix it a lock ring.

Pressing a rod, utaplivay it in the case of the diaphragm mechanism. (At the closed gate of the first camera the second has to remain closed).

Holding a diaphragm rod drawn in, we open the lever the gate of the first camera, at the same time the gate of the second camera has to open automatically. If the gate opened not completely – we shorten draft. Upon termination of adjustment we tighten a draft lock-nut.

Malfunction of a pneumatic actuator is often caused by violation of tightness of channels on which depression moves to a diaphragm. In this case it is necessary to check the lower plane of the case of the carburetor (see Dismantling and repair of the case of the carburetor). As a result of pulling of nuts of fastening of the carburetor it can be bent – the necessary depression at the same time is not created and the gate of the second camera does not open or opens not completely, with delay.