CONCRETE PUMP VALVE SYSTEM

Advantages of S valve over Gate valve system

1. High rise pumping

• The ‘S’ valve concrete pump is preferred over the gate valve pump for high rise pumping application.
• This is due to the fact that the fine material (slurry) leakage from the pressure line is very less when compared with the gate valve pump.
• Because the main leakage point in the S valve system pressure line is the gap between the wear plate & the cutting ring. In the factory setting, this gap will be lesser than 0.5mm. Further, in the service life also, the compensating (or energizer) ring which acts as a spring, keeps this gap constant despite wear.
• So, with S valve pump, even water can be pumped with up to a pressure of 60 bar.
• But, in the gate valve pump, the gap between the cup body and the gate valve can be up to 5mm. so, there is more chance of slurry leakage at high concrete pressure (above 85 bar).
• The leakage is evident from the fact that we cannot pump water using the gate valve pump. Even during testing in our factory we close the outlet (pressure line) of the pump, which means that the pump should develop maximum pressure. But, we do not get any pressure in the concrete piston.
• If the slurry leakage happens, the concrete becomes stiffer & it cannot be pumped.
• So, generally for applications involving a concrete pressure more than 85 bar, the S valve pump is preferred over the gate valve pump.

2. Maintenance

• The switching operation in the S valve pump is an oscillating motion. But in the gate valve pump it is an impact load. Because of this, the gate valve system (E.g. plunger hydraulic seals, concrete seals & cup bodies) requires more frequent maintenance than S valve.

Disadvantage

• The S valve pump is poor in suction performance when compared with the gate valve pump.
• This is due to the restriction (of the S valve) in the hopper. So, it will be difficult to pump concrete with less fine material content.
• To avoid these problems, the S valve pumps in India are normally coming with large suction apertures (minimum 180 dia) and low lying agitators.