Basic knowledge of flange butterfly valve
The flange butterfly valve introduces the self sealing design concept, in which the connection between the valve office and the valve shaft adopts the patented pull-out pin structure. The valve] is characterized by reliable sealing, bi-directional sealing, tight connection and no loosening, so that the valve can be used for a long time. Its features are as follows:
Bidirectional sealing
Generally, due to its structure, the traditional butterfly valve can not be well sealed under the working pressure in the opposite direction (not conducive to the sealing direction). At present, there are no mandatory provisions on two-way sealing in relevant national standards. This is due to:
1. Adopt self sealing design concept
The valve disc seal is directly embedded into the valve disc in a sawtooth shape with rubber without using pressure plate or bolt fixation, so as to avoid the problems of uneven stress in the sealing country caused by the traditional bolt pressing plate seal, bolt falling off and premature damage of the sealing ring. Under the action of the working pressure in the opposite direction, the sealing ring generates a self sealing force, which increases the sealing specific pressure and compresses the valve seat. The greater the working pressure in the opposite direction, the greater the self sealing force, so as to closely combine the sealing ring with the valve seat and achieve the effect of two-way sealing.
2. The valve disc has good rigidity and is not easy to deform
The valve disc above DN300 of butterfly valve is of double plate truss flow-through structure, with small flow resistance and good rigidity. It is not easy to deform under the working pressure in the opposite direction, so that the seal will not be separated from the best sealing point of the valve seat with the deformation of the valve disc, so as to ensure the sealing effect of the sealing ring.
3. Long service life of rubber seal Park
(1) due to the self sealing design concept, the small interference between the rubber seat and the stainless steel seat only maintains the initial seal, so the specific pressure required for sealing increases with the increase of system pressure.
(2) in addition, the so-called breathing groove for rubber elastic concession is reserved in the serrated groove, so that the rubber has a certain expansion space when under pressure, so that it will not produce elastic fatigue in long-term work, so the service life of the seal is greatly increased compared with the traditional type.
Unique bottom axial adjustment locking device design
For butterfly valves with specifications above DN300, considering the reliability of self weight sealing of butterfly plate, the position of valve disc on valve seat is in the best sealing state through precise adjustment and fixation of axial position during manufacturing. For the valve flap sagging that may be caused during long-term use, it is also convenient to further adjust the locking to achieve zero leakage for long-term use.
The sealing state is easy to replace
When the sealing ring needs to be replaced, there is no need to remove the valve disc. Just open the valve fully, take out the key in the operating device, keep connected with the main valve key after adjusting the operating device to the closed state, and then continue to rotate the handwheel in the opening direction until the sealing ring is located on the opposite side of the valve body seal.