Great Wall ZVA automatic Nozzle
The ZVA is a fuel-dispensing nozzle with an automatic safety shut off for wet-hose use with electrical operated petrol dispensing pumps.
How the ZVA automatic works:
The flow through the nozzle creates a vacuum at the valve seat. Air is drawn in through the sensing port at the tip of the spout, through the safety cut-out, past the diaphragm, and into the fuel. The valve will remain open while the air flows reely.When fuel reaches the sensing port, suction builds up rapidly until it lifts the diaphragm and trips the automatic action which shuts the valve. The mechanic also trips if the ball of the safety cut-off rolls back to obstruct the free air flow. It will also occur if the spout is pointed upwards or if the nozzle is dropped onto the ground. The valve opens with the flow, allowing smooth low control for to-the-penny dispensing.It closes against the flow for a soft shock-less closure