1. Repair method
When the valve core is detached and cannot be cut out, the valve cover, the valve stem, the copper sleeve, the packing and the gland can be changed without the valve body, the valve core and the valve seat being sealed by the sealed medium. After the assembly method, the valve core is exposed, and the valve stem is reconnected with the valve core by a conventional method, so that the three seals of the valve can be continuously maintained and the valve can be reopened. After the bonnet is disassembled, except for the special valve, the wedge angle of the valve spool is in the friction angle range. No matter how the pressure is applied to the end faces of the valve core, the valve core will not be squeezed out from the valve seat under the self-locking condition. The spool is less likely to be squeezed out.
2. Operation steps
(1) Taking the open wedge valve as an example, when the connection between the valve stem and the valve core fails, the hand wheel can still rotate, and the valve core can be returned to the valve seat through the hand wheel to ensure the sealing surface of the valve core and the valve seat. The seal between the two is a prerequisite for applying this repair method. First unscrew the valve packing cap nut, loosen the packing, and then loosen the nuts on all the bolts on the bonnet in turn, but do not completely unscrew them.
(2) Continue to turn the handwheel in the direction of closing. At this time, the valve stem will not move any more. Instead, the upper part of the valve cover is separated from the valve body. The operation of this part is to observe the seal between the sealing surface of the valve core and the valve seat. Whether it is sealed, if the sealing is not tight, there is leakage of the medium, as long as the amount is not large, it will not affect the on-site construction treatment in a short time, then the nuts on all bolts can be completely unscrewed, and the upper part of the valve cover and the valve are removed. The rod exposes the top end of the valve plug in the valve seat, checks the original connection mode of the valve stem and the valve core, and the cause of the failure, and formulates a solution.
(3) Gently rotate the valve stem in the upper part of the bonnet, and withdraw from the stem nut and stuffing box. Also, turn the lock nut of the stem nut down and remove the handwheel and stem nut. Unlimited is free to rotate.
