Two-Stage Closure
The E-7 valve has two solenoids to control the two-stage closure of the valve. During full flow, solenoid valve one (S1) opens and solenoid valve two (S2) closes. During dwell flow, S1 closes and S2 opens. In dwell flow, S2 closes to end deliveries. Shut-off during dwell flow reduces the risk of liquid hammer and accurately ends preset deliveries.
Valve Closed
When the E-7 Valve is closed, it is not possible to make a delivery. The S1 and S2 solenoids are both de-energized and closed. Fluid enters a port on the inlet side of the valve and flows through the tubing and the S1 solenoid into the valve chamber on the back side of the piston. Using this fluid pressure from the pump and the compression spring, the piston seals the inlet to the valve.
Flow Control Switch Closed |
The flow control switch is closed and does not allow any supply air to pass though the inlet of the flow control switch. |
Orientation of the Air Switch Ports |
The ports of the air switch are shown facing the front for instruction purposes only. These ports must be oriented so that the ports face the top or bottom of the air switch. The system ships with ports facing the top, which Liquid Controls recommends. A vertical position allows any condensation from the air pump to drain. |
Flow Control Switch |
The flow control switch is actuated by the shaft of the valve piston. When this occurs, the inlet air is can pass through the switch to the outlet. Typically, this outlet air routes to the air-operated valve on the pump to increase bypass pressure. It can also be routed to the engine throttle to increase the shaft RPM for the pump, which increases flow. |
LectroCount3 |
For LectroCount³, both solenoids will energize during full flow. |
Dwell Flow
When making a preset delivery, the system will transition from full-flow to dwell-flow near the end of delivery. At the point when dwell-flow begins, the S1 solenoid valve de-energizes at the same instant the S2 solenoid valve energizes.
After the S1 solenoid closes, the piston and compression spring move back into position and close the path through the valve. When the S2 solenoid valve energizes, it opens a path for the liquid from the front of the valve, through the solenoid, and to the outlet side of the valve. When the preset delivery volume is reached, the S2 solenoid valve closes and the delivery ends.
Flow Control Switch |
The piston from the valve will de-energize the internal switch of the flow control switch. The outlet closes and air pressure in the outlet line vents though the vent port on the flow control switch, allowing the air-operated valve on the pump to close. If the outlet air is also connected to the throttle of the vehicle, it will reduce RPMs to the pump shaft as well. |
LectroCount3 |
For LectroCount³, the S1 solenoid will de-energize during dwell-flow and the S2 solenoid will remain energized until the delivery preset is reached. |
