The three valve needle valve is an adjustable valve with a wide range of applications, such as the cutting distance for flame cutting and the knob for adjusting flame temperature. Instrument needle valve is an important component of instrument measurement pipeline system, mainly including globe valve and ball valve, which is used to open or cut off pipeline passage. The valve core of a needle valve is a pointed cone that is inserted into the valve seat like a needle, hence the name.

 

When connecting flow or differential pressure sensor instruments to process pipelines, a three valve group should be used for the following purposes:

 

1. When the medium is added to the pipeline from the initial state (empty), the pressure on both sides of the sensor will suddenly change, and if the pressure difference is too large, it may damage the sensor of the transmitter. To avoid this, valves A and B on both sides of the sensor should be closed first, and bypass valve C should be opened;

 

2. After the medium fills the pipeline and approaches stability and balance, open one of A or B to evenly apply pressure on both sides of the sensor;

 

3. Close valve C and open the other valve in A or B, and the sensor will start working normally;

 

4. The order of closure is opposite to the above situation.