Connect a non-return valve at the entrance of the solenoid valve, there is an arrow on the non-return valve.
Solenoid valve P is the air inlet, A is the air outlet, B is the air outlet, block B, R and S are the exhaust.
Quick exhaust valve, P is the air inlet, A is the air outlet, R is the exhaust.
This connection is to keep the valve normally closed while power off
The slow valve opening speed is related to the elasticity of the hose and the exhaust speed in the valve cavity. A quick exhaust valve can be selected to increase the valve opening speed.