Oil dilution control

Claim 3

A refrigeration apparatus including a refrigerant compressor having a lubricating oil reservoir containing a supply of lubricating oil and a control mechanism for maintaining a substantially constant level of refrigerant concentration in the lubricating oil, said control mechanism comprising an oil heater mounted in heat exchanging relation with the oil in said reservoir, said heater being operable when energized to raise the oil temperature, sensing means continuously sensing the refrigerant vapor pressure and oil temperature, and heater energizing means for energizing said heater in response to said sensing means sensing a differential, exceeding a predetermined range, between said refrigerant vapor pressure and oil temperature.

Claim 4

A refrigeration apparatus including a refrigerant compressor having a lubricating oil reservoir containing a supply of lubricating oil and a control mechanism for maintaining a substantially constant level of refrigerant concentration in the lubricating oil, said control mechanism comprising an oil heater mounted in heat exchanging relation with the oil in said reservoir, said heater being operable when energized to raise the oil temperature, sensing means continuously sensing the refrigerant vapor pressure and oil temperature, and heater energizing means for energizing said heater in response to said sensing means sensing a differential, exceeding a predetermined range, between said refrigerant vapor pressure and oil temperature.

Claim 5

A refrigeration apparatus including a refrigerant compressor having a lubricating oil reservoir containing a supply of lubricating oil and a control mechanism for maintaining a substantially constant level of refrigerant concentration in the lubricating oil, said control mechanism comprising an oil heater mounted in heat exchanging relation with the oil in said reservoir, a power supply for operating said heater to raise the temperature of the oil in said reservoir, means operable to continuously produce a signal indicative of the vapor pressure of the refrigerant coNtacting the oil in said oil reservoir, a temperature sensing means operable to continuously produce a signal indicative of the temperature of the oil in said reservoir, and heater control means responsive upon the sensed refrigerant pressure signal exceeding the sensed oil temperature signal by a predetermined amount to connect said heater to said power supply.

Claim 6

A refrigeration apparatus including a refrigerant compressor having a lubricating oil reservoir containing a supply of lubricating oil and a control mechanism for maintaining a substantially constant level of refrigerant concentration in the lubricating oil, said control mechanism comprising an oil heater mounted in heat exchanging relation with the oil in said reservoir, a power supply for operating said heater to raise the temperature of the oil in said reservoir, means operable to continuously produce a signal indicative of the vapor pressure of the refrigerant coNtacting the oil in said oil reservoir, a temperature sensing means operable to continuously produce a signal indicative of the temperature of the oil in said reservoir, and heater control means responsive upon the sensed refrigerant pressure signal exceeding the sensed oil temperature signal by a predetermined amount to connect said heater to said power supply.

Claim 7

A refrigeration system including a refrigerant compressor having a lubricating oil reservoir and control mechanism for maintaining a substantially constant level of refrigerant concentration in the compressor lubricating oil, said control mechanism comprising a heater mounted in said oil reservoir, a power supply for operating said heater to raise the temperature of the oil in said reservoir, a first measuring means for continuously measuring the vapor pressure of the refrigerant contacting the oil in said reservoir, a second measuring means for continuously measuring the temperature of the oil in said reservoir, and heater control means responsive to a differential exceeding a predetermined range, as measured by said first and second means, to connect said heater to said power supply to maintain a substantially constant level of refrigerant concentration in said oil supply.

Claim 8

A refrigeration system including a refrigerant compressor having a lubricating oil reservoir and control mechanism for maintaining a substantially constant level of refrigerant concentration in the compressor lubricating oil, said control mechanism comprising a heater mounted in said oil reservoir, a power supply for operating said heater to raise the temperature of the oil in said reservoir, a first measuring means for continuously measuring the vapor pressure of the refrigerant contacting the oil in said reservoir, a second measuring means for continuously measuring the temperature of the oil in said reservoir, and heater control means responsive to a differential exceeding a predetermined range, as measured by said first and second means, to connect said heater to said power supply to maintain a substantially constant level of refrigerant concentration in said oil supply.

Claim 9

A control mechanism as set forth in claim 4 wherein said first and second measuring means consists of thermal systems operable to produce pressure signals indicative of the refrigerant vapor pressure and oil temperature respectively and said heater control means consists of a differential pressure operated switch means.

Claim 10

A control mechanism as set forth in claim 4 wherein said heater control consists of a differential pressure operated switch means, said first measuring means includes a passage means for conveying refrigerant pressure to said switch means and said second measuring means consists of a closed thermal responsive system containing a temperature responsive fluid medium for producing a force within said system commensurate with the oil temperature and applying said force to said switch means.

Claim 11

Refrigeration apparatus including a compressor having a lubricating oil reservoir containing supply of lubricating oil and control mechanism for maintaining a constant level of refrigerant concentration in the compressor lubricating oil; said control mechanism comprising a heater mounted in heat exchanging relation to the oil in said oil reservoir; a power supply for said heater; a first thermal responsive system containing a temperature responsive fluid medium for producing a variable pressure representing a force within said system; said system sensing the temperature in the low side of said refrigeration system; a second thermal responsive system containing a temperature responsive fluid medium different from said first fluid medium for producing a variable pressure representing a force within said second system; said second system sensing the temperature of the oil in said reservoir; the force created by expansion of fluid within the first system acting in opposition to the force created by expansion of fluid within the second system, and the rate of variation between the force and temperature in said first system being different from the rate of variation between the force and temperature in said second system so that a predetermined force differential within the two systems is substantially independent of a fixed temperature difference between the ambient temperature in said low pressure side and the oil temperature in said reservoir; and means responsive to a predetermined force differential as measured by said systems to establish connection of said heater to said power supply.

Claim 12

Refrigeration apparatus including a compressor having a lubricating oil reservoir containing supply of lubricating oil and control mechanism for maintaining a constant level of refrigerant concentration in the compressor lubricating oil; said control mechanism comprising a heater mounted in heat exchanging relation to the oil in said oil reservoir; a power supply for said heater; a first thermal responsive system containing a temperature responsive fluid medium for producing a variable pressure representing a force within said system; said system sensing the temperature in the low side of said refrigeration system; a second thermal responsive system containing a temperature responsive fluid medium different from said first fluid medium for producing a variable pressure representing a force within said second system; said second system sensing the temperature of the oil in said reservoir; the force created by expansion of fluid within the first system acting in opposition to the force created by expansion of fluid within the second system, and the rate of variation between the force and temperature in said first system being different from the rate of variation between the force and temperature in said second system so that a predetermined force differential within the two systems is substantially independent of a fixed temperature difference between the ambient temperature in said low pressure side and the oil temperature in said reservoir; and means responsive to a predetermined force differential as measured by said systems to establish connection of said heater to said power supply.

Claim 13

A control mechanism as set forth in claim 1 wherein said means responsive to said predetermined force differential consists of a pressure operated switch operable when actuated by said force differential to connect said heater to said power supply.

Claim 14

A control mechanism as set forth in claim 1 wherein said first thermal responsive system inCludes a bulb partially filled with refrigerant R-12 and said second thermal responsive system includes a bulb partially filled with ethyl chloride.