Control Valve leak seal

⒈ Leaking condition and leaking medium parameter：

 ⑴. Leaking condition： DN350 control valve body leak at hydrogen production plant.

 ⑵. Leaking medium parameter：

2.  Sealing method

 ⑴ Clamp design

 ① To enclose the valve body with box type of clamp for setting up the sealing cavity for sealant.

 ② Clamp design and key dimension

a.  Clamp outer shape dimension:1000×1000×1000 cubic millimeter of box clamp；

b. End plate and side board thickness 40mm（material  for Q235）；

c. Injection port structure and quantity: 12 ×M20 injection ports，6 ×M12 standard injection ports；

d.  injection port：open the standard injection ports at the leaking location, and M20 injection port in nearby region.

⑵. Sealant selection and use quantity

 ① Apply Txy-18# injectable sealant;

 ② Quantity:300kg.

⑶ Injection approach

① With 4 injection guns, inject symmetrically from two sides；

② Inject at initial port which is furthest away from the main leaking point，control the injection pressure and pump steadily；

③ Focus on the coordination between the injection speed and the sealant curing time；

④ inject at the main leaking port after the sealant get cured at other area in the sealing cavity；

⑤ Slowly and steadily pump; the operation pressure should be moderately higher than the system pressure.

3,  Safety protection

  ⑴ Prevent fire and explosion; no open flame; prevent static and shock discharge;

  ⑵ Steam dilution reduce gas concentration to lower than the lower explosive limit；

  ⑶ Use non-spark tool；

  ⑷ Operator should wear anti-static cloth and shoes.

4 Observe the effect and make addition injection for partial injection ports for sealant packing down.

5,  Operation procedure control and project quality

⑴ Clamp material and thickness selection

①End plate and side board use Q235-A；

②Use clamp thickness 40mm; box type of clamp.

⑵Reinforcement measure and sealant selection

①Sealant TXY-18# has effect of pressure bearing and reinforcing after curing；

②The injectable sealant could help enhance the performance of pressure bearing in new sealing structure；

③Ambient temperature could ensure the reinforcement stability.

⑶. Sealing procedure and strength guarantee

①Multi-ports for pressure releasing before initial injection;

②Under the influence of system temperature, the injectable sealant gradually transform to elastic body;

③In the process of injection, the sealant cavity volume and pressure change;

④The sealant cured could bear the partial load for the clamp；

⑤Slowly pumping at the final injection port could help fill full, compaction, and balance system pressure;

⑥Strictly control the packing force to avoid overload at partial region; to secure the structure stability.