a solenoid driven valve is disclosed which is adaptable for controlling the introduction of a high pressure fluid into a fluid trapping assembly having an absorption column topped with an annular orifice expansion nozzle . the valve has an inlet port to introduce high pressure fluid , an axially moving solenoid driven pin which engages means to restrict fluid flow into said column . a diaphragm is located within the valve to direct fluid into the column and which separates the fluid in a region of high pressure from ambient pressures .