6. Operations and Adjustments
PNEG-2174
Sampler - Model GRA
25
Pneumatic Components
Sample Cutter Traverse Valve V-1
This valve is a 4-way, 2 position, dual solenoid operated control valve. This valve controls the air cylinder,
alternately pressurizing one side or the other of the air cylinder to traverse the sample pelican. The valve
has two manual over-ride buttons that allows the operator to cycle the sample cutter traverse air cylinder
without the aid of the controller. By pushing a manual over-ride button, the internal valve spool is
positioned manually and the sample pelican will traverse to the other side.
NOTE:
The manual over-rides will only work when the control power is OFF.
Figure 6B Solenoid Valve
Speed Control Valves
A speed control valve is threaded into each exhaust port of Valve V-1.
Each speed control
valve controls the rate at which air exhausts from one end of the cylinder and as a result, controls cylinder
operating speed in only one direction. The speed controls were factory set but may need minor adjustment
due to differences in air supplies. Use the following guidelines when adjusting the speed controls.
1. Turn the nut locking the one speed control valve’s metering screw clockwise to loosen it.
(
NOTE:
Left hand threads.)
Do not allow metering screw to turn.
2. Change control switch to manual mode and initiate a manual sample. While operating the sampler,
turn the metering screw to vary the speed of cylinder operation. Turn the screw clockwise to
decrease speed or turn the screw counterclockwise to increase speed.
3. When the desired cylinder operating speed in one direction has been achieved, tighten the nut to lock
the adjustment and repeat procedure to adjust the other speed control valve.
Ref #
Description
1
Solenoid
2
Manual Over-Ride
3
Metering Screw Lock Nut
4
Air Supply Port
5
Flow Control Metering Screw
6
Mesh Screen
Escape of pressurized air, fluids and contaminants at high velocity can cause
injury to unprotected eyes. Always wear eye protection when servicing air valves
and components.
