11. Engine and chain-drive lubrication used a total-loss oil system, controlled by a small pump and needle valve . 12. The needle valve is controlled by an aneroid bellows, causing a leaning of the mixture as altitude increases. 13. Two main types are used : the fixed orifice and the adjustable orifice ( usually a needle valve ). 14. After donning safety glasses and hearing protection a check is made to ensure the needle valve is fully closed. 15. From there the tube runs to a needle valve that controls the amount of gas flowing to the balloon. 16. In 1957, the Spanish company started producing gate valves, check valves, needle valves and butterfly valves for the marine industry. 17. The solenoid lifts the needle valve from the valve seat, and fuel under pressure is sent in the engine cylinder. 18. A true needle valve uses a tapered needle in a tapered seat, so as to provide fine control over flow rate. 19. It operates by bleeding higher pressure air from chamber B into chamber A as it flows though a tapered needle valve . 20. The needle valve is controlled by an aneroid bellows that senses barometric pressure, causing a leaning of the mixture as altitude increases.
