Archive for February, 2017

The Balance Ratio of Pilot Valve and the Selection of Balance Valve

The balance valve pilot ratio is the ratio of the pilot area to the overflow area, meaning that this value is also equal to: When the balance valve spring is set to a fixed value, there is no pilot oil required to open its pressure separately from the pilot oil to open it Pressure ratio.

Balance valve pilot ratio

Pilot Ratio = [Overflow Pressure Setting – Load Pressure] / Pilot Pressure
When there is no pressure oil in the pilot port, the equilibrium opening pressure is the spring setpoint. If there is no pilot fuel supply, the balancing valve is opened by the load and the pressure drop increases drastically as the flow rate  pipe welding machine increases (this is also the balancing load). If pilot pressure = (setpoint – load) / area is less than the internal pilot pressure, the opening pressure can be set by adjusting the relief valve bolt. Specific formula Opening pressure = (set pressure – maximum load pressure) / valve pilot ratio

Angle Drilling machineWhen there is no pressure oil in the pilot port, the equilibrium opening pressure is the spring setpoint. If there is no pilot fuel supply, the balancing valve is opened by the load and the pressure drop increases drastically as the flow rate increases (this is also the balancing load). Pilot pressure = (setpoint-load) / area ratio angle cutter machine, regardless of outlet pressure
For the balance valve, if the pressure ratio is 3: 1, due to the pilot oil and the inlet port corresponding to the force of the spool has a different ratio of 3: 1 proportional relationship, so open the spool required control pressure is low, Pressure and inlet pressure to open the proportion of the spool is approximately 1: 3
Pilot ratio
3: 1 (standard) for the load changes in the situation and the stability of the load of construction machinery.
8: 1 applies to the load requirements drilling equipments to maintain a constant state.
Different workplace and environment, the choice of the pressure ratio is not the same, simple in the load, outside the case of small interference generally choose a large ratio of liquid control, which can reduce the pilot pressure value, energy saving. In the load disturbance, easy vibration of the occasion generally choose a smaller pressure ratio, to ensure that the pilot pressure fluctuations will not cause frequent vibration drilling machine balance spool.
Balance valve selection Note:
1, the flow rate can be slightly higher than the rated flow of work;
2, as far as possible with a low pilot than the valve, more stable;
3, the balance valve is used to control the pressure, non-speed;
4, all the set pressure is the opening pressure;
5, can not be used as a relief valve;
6, as close to the actuator, to prevent hose burst.