Oil level control apparatus

An oil level control device for a compressor in a refrigeration system which includes an oil reservoir for holding a supply of oil and being in fluid communication with said compressor, said compressor having an oil pump and an oil sump, said apparatus comprising:

• an oil level sensor in fluid communication with said compressor, said oil level sensor comprising a housing in which a chamber is formed, said housing adapted for attachment to a wall of said compressor and provided with a first duct for spacing and providing fluid communication between said compressor and said chamber, said first duct stabilising oil within said chamber so that the oil in said chamber is substantially stagnant;
• and a second duct located above said first duct through which refrigerant vapour disassociating from said oil in said chamber can be returned to said compressor;
• a float member pivotally mounted in said chamber in fluid communication with said oil sump;
• a float position sensor for sensing the angle of pivoting of said float member and producing a signal indicative of the oil level within said compressor;
• and,
• control means for operating a valve adapted for controlling fluid communication between said oil sump and said reservoir;
• wherein, when said signal is indicative of the oil level in said oil sump being less than a predetermined minimum level, said control means operates to open said valve so that oil from said oil reservoir can flow into said oil sump to increase the oil level within said sump to above said predetermined minimum level.

An oil level control apparatus for a compressor in a refrigeration system which includes an oil reservoir for holding a supply of oil and being in fluid communication with said compressor, said compressor having an oil pump and an oil sump, said apparatus comprising:

• an oil level sensor in fluid communication with said compressor for producing a signal indicative of the level of oil within said compressor;
• control means for operating first and second valves, said first valve adapted for controlling fluid communication between said oil sump and said reservoir and said second valve adapted for controlling fluid communication between said oil pump and said oil reservoir, said control means further including delayed alarm means;
• wherein, when said signal is indicative of the oil level in said compressor being less than a first predetermined minimum level, said control means operates to open said first valve and close said second valve providing fluid communication between said sump and said reservoir so that oil from said oil reservoir can flow into said oil sump and in the event that after a predetermined time delay from the initial operation of said first valve, the oil level within said sump has not exceeded said first predetermined minimum level, said control means activates said delayed alarm means to provide an alarm indication;
• when said signal is indicative of the oil level in the compressor being greater than a predetermined maximum level, said control means operates to open said second valve and close said first valve providing fluid communication between said oil pump and said oil reservoir so that said oil pump can pump oil from said sump to said oil reservoir;
• and, when said signal is indicative of the oil level being between said predetermined minimum and maximum levels, said control means operates to close both said first valve and said second valve to prevent oil flow between said compressor and reservoir via said first and second valves.

An oil level control device for a compressor in a refrigeration system which includes an oil reservoir for holding a supply of oil and being in fluid communication with said compressor, said compressor having an oil pump and an oil sump, said apparatus comprising:

• an oil level sensor in fluid communication with said compressor, said oil level sensor including a housing in which a chamber is formed, said housing adapted for attachment to a wall of said compressor and having separate first and second ducts, said first duct for spacing, and providing fluid communication between, said compressor and said chamber, and acting to stabilize oil within said chamber so that the oil in said chamber is substantially stagnant, and said second duct located above said first duct and providing a path through which refrigerant vapour disassociating from the oil in said chamber can return to said compressor;
• a float member pivotally mounted in said chamber, and a float position sensor for sensing the angle of pivoting of said float member and producing a signal indicative of the oil level within said compressor;
• control means for operating a valve adapted for controlling fluid communication between said oil sump and said reservoir, said control means including a delayed alarm means;
• and
• wherein, when said signal is indicative of the oil level in said oil sump being less than a predetermined minimum level, said control means operates to open said valve so that oil from said oil reservoir can flow into said oil sump to increase the oil level within said sump to above said predetermined minimum level, and in the event that after a predetermined time delay from the initial operation of said first valve, the oil level within said sump has not exceeded said first predetermined minimum level, said delayed alarm means is activated to produce an alarm indication.