Vane Compressors Flashcards
Does a sliding bane compressor have a built in pressure ratio?
Yes they do.
What causes the blades to extend and form a seal?
The rotation of the rotor causes the blades to sling out against the housing. The oil or the blade material forms the seal.
Is thrust created by the airflow through a sliding vane compressor?
No, no thrust is created.
What causes oil pressure to develop in an oil flooded vane compressor?
The minimum pressure valve
What is the purpose of oil in a sliding vane compressor?
It seals, lubricates and cools the compressor
Is the pressure ration adjustable in a sliding vain compressor?
No the pressure ratio is not adjustable
What is the typical minimum pressure for the minimum pressure valve to own on a sliding vain compressor? According to the module
60 psi
What valve directly controls the unloaded valve?
The servo valve
How does the air control system work on a sliding vane compressor?
When the compressor is at rest (shut down) the pressure in the casing is at atmospheric pressure. This will hold the servo valve in the closed position which keeps the oil in the sump.
On start up the servo will remain closed and the unloaded valve will be open, the system pressure will begin to build, when the maximum working pressure is achieved. The air pressure will force the oil in the sump to overcome the spring pressure of the servo valve. This opens a small oil feed line that presses on the back side of the unloaded valve forcing it to shut. Once air pressure decreases the sump pressure will decrease causing the servo valve to close slightly and in then opening the unloaded valve to allow more air into the system.
What is an oil return valve on a sliding vane compressor?
The oil return valve is located under the oil separators near the discharge. It allows the oil that drops out through the separator element to return to the system. It does not go back to the reservoir though it goes to the inlet.
What is the oil relief valve on a sliding vane compressor?
It is a relief valve that is installed just before the discharge port. As the oil moves in rotation from suction to discharge it builds pressure and allows this valve to open so less oil is carried into the discharge.
What is the oil release valve?
The oil release valve is located at the bottom of the stator and prevents the system from having hydraulic lock. When the system is running the sump pressure pushes against a small disc that will keep this oil from returning back to tank and when the system is off the sump pressure will diminish and the disc will drop allowing any oil in the valve to drain out into the reservoir.
What is the main purpose of the safety relief valve on a sliding vane compressor?
The main purpose of this spring loaded valve is to provide a safeguard against over pressurization on the casing. This valve is used to unload the compressor on start-up.
What is the purpose of the bypass valve on a sliding vane compressor?
It acts the same way as a thermal mixing valve on a screw compressor.
What kind of bearings does a sliding vane compressor use?
Journal bearings.
