Meter Out Circuit Diagram
The Meter out circuit diagram is shown in the figure below.
|Meter-Out Circuit Diagram|
In the meter-out circuit, the flow control valve is connected in the secondary line, directly after the load. The following measure of pressure is taken at various pressure gauges.
Pressure Gauge P1: It indicates the Pmax as set by the pressure relief valve. This pressure is formed on the left side volume of the cylinder, irrespective of the load; hence sealing in this side is always subjected to maximum pressure.
Pressure Gauge P2: It indicates the pressure ON, which is determined by the difference between the pressure Pmax and the load pressure. This difference depends on the ratio of the two-piston areas.
Pressure Gauge P3: Pressure in the return stroke is always equal to 0.
In this circuit, speed control is achieved by changing the flow adjustment of the flow control valve, which controls the flow coming out from the piston rod end of the cylinder.
Hence, also it should be noted that in a given circuit, flow control is in the forward direction only i.e. in return stroke the flow of the pump to the piston rod end of the cylinder is bypassed through the check valve.
Advantages of meter-out circuit
- The load is always under pressure from both sides, thus it is counterbalanced.
- Even when the load changes the direction, no uncontrolled jerk motion occurs.
Disadvantages of meter-out circuit
The left side of the cylinder is always under maximum pressure even with a minimum load. Due to continuous pressure from both sides, there is more friction and less seal life.
Meter Out Circuit Applications
Meter-out circuits are found to be successful in operations like drilling, boring, reaming, etc.
In such operations where the drills and mills passing through the workpiece often tend to drag the entire tool unit forward, in such a situation meter-out circuit is the best solution.