Air conditioner servicing unit

Claim 2

A servicing unit for air conditioning systems comprising a charging line containing a constant flow metering device adapted to pass charging fluid at a regulated rate, said line extending from said source and leading to a connector for connection to a charging fitting of the air conditioning system, a source of liquid refrigerant under pressure, and a line containing a control valve connecting said source to the constant flow metering device, a source of oil under pressure and a line containing a control valve connecting said oil source to said same constant flow metering device, and timing means connected to said control valves and operative to control the time during which flow occurs through said lines to the system, and thereby to meter to the system a quantity of fluid determined by said rate and the time.

Claim 3

A servicing unit for air conditioning systems, comprising a constant flow valve operative to pass a liquid at a constant flow rate and a line leading therefrom and adapted for connection to an air conditioning system to charge the same, a source of liquid refrigerant under pressure, and a line containing a control valve connecting the same to the constant flow valve, a source of lubricating oil under pressure and a line containing a control valve connecting the same to the constant flow valve in parallel with the refrigerant line, said valves being operative to selectively deliver either oil or refrigerant to the constant flow valve for delivery to the air conditioning system.

Claim 4

A servicing unit for air conditioning systems, comprising a constant flow valve operative to pass a liquid at a constant flow rate and a line leading therefrom and adapted for connection to an air conditioning system to charge the same, a source of liquid refrigerant under pressure, and a line containing a control valve connecting the same to the constant flow valve, a source of lubricating oil under pressure and a line containing a control valve connecting the same to the constant flow valve in parallel with the refrigerant line, said valves being operative to selectively deliver either oil or refrigerant to the constant flow valve for delivery to the air conditioning system.

Claim 5

A servicing unit as in claim 2 with the addition of control means for selectively predetermining the time period during which one of said sources is connected to deliver its fluid to the constant valve and system.

Claim 6

A servicing unit as in claim 2, for servicing an air conditioning system comprising a compressor having suction and discharge ports, in which said line from the constant flow valve is adapted to be connected to the suction side of the system, said constant flow valve having a restricted orifice means of a size to pass oil at a slow rate insufficient to damage the operating compressor and of such size that under normal operating conditions refrigerant will remain substantially in liquid state thereto, the line leading from the constant flow valve being such that there will be a pressure drop beyond such orifice means so as to cause at least substantial atomization or vaporization of the refrigerant before it enters the compressor being charged.

Claim 7

A servicing unit as in claim 2 with the addition of a vacuum pump connected through a control valve to the line leading from the constant flow valve to the aIr conditioning system.

Claim 8

A servicing unit for servicing an air conditioning system, which includes a compressor having suction and discharge ports, comprising a constant flow valve and a line leading therefrom and adapted for connection to the suction side of an air conditioning system to charge the same, a source of liquid refrigerant under pressure, and a line containing a control valve connecting the same to the constant flow valve, a source of lubricating oil under pressure and a line containing a control valve connecting the same to the constant flow valve, said valves being operative to selectively deliver either oil or refrigerant to the constant flow valve for delivery to the air conditioning system, and a high-pressure line adapted to be connected to the high pressure side of the system, said high-pressure line containing a discharge valve for discharging the contents of the system.

Claim 9

A servicing unit for servicing an air conditioning system, which includes a compressor having suction and discharge ports, comprising a constant flow valve and a line leading therefrom and adapted for connection to the suction side of an air conditioning system to charge the same, a source of liquid refrigerant under pressure, and a line containing a control valve connecting the same to the constant flow valve, a source of lubricating oil under pressure and a line containing a control valve connecting the same to the constant flow valve, said valves being operative to selectively deliver either oil or refrigerant to the constant flow valve for delivery to the air conditioning system, and a high-pressure line adapted to be connected to the high pressure side of the system, said high-pressure line containing a discharge valve for discharging the contents of the system.

Claim 10

A servicing unit for an air conditioning system to which refrigerant should be delivered in substantially vaporized or atomized state, comprising a source of refrigerant in liquid state under pressure which may vary under different conditions, a charging line extending from said source and leading to a connector for connection to a charging fitting of the air conditioning system, said line containing a constant flow metering device which includes two orifice means in series relation, and means responsive to the pressure drop across one of said orifice means to vary the pressure drop across the other orifice means in a direction to compensate for variations in the pressure drop across the first and thereby to provide a substantially constant flow rate for liquid through the metering device, the said orifice means being of such size as to cause the refrigerant to remain substantially in liquid state to the second orifice and thereby to be metered as liquid at such constant flow rate, and of such size that under normal operating conditions there will be a pressure drop at and beyond such second orifice means sufficient to cause at least substantial atomization and vaporization of the refrigerant before it enters the system being charged, a shut-off valve in said line, and a timer connected to control said shut-off valve and operative to open said valve for a predetermined time and thereby produce refrigerant flow at such constant flow rate for such predetermined time so as to deliver a measured quantity of refrigerant to the system being charged.

Claim 11

A servicing unit for an air conditioning system to which refrigerant should be delivered in substantially vaporized or atomized state, comprising a source of refrigerant in liquid state under pressure which may vary under different conditions, a charging line extending from said source and leading to a connector for connection to a charging fitting of the air conditioning system, said line containing a constant flow metering device which includes two orifice means in series relation, and means responsive to the pressure drop across one of said orifice means to vary the pressure drop across the other orifice means in a direction to compensate for variations in the pressure drop across the first and thereby to provide a substantially constant flow rate for liquid through the metering device, the said orifice means being of such size as to cause the refrigerant to remain substantially in liquid state to the second orifice and thereby to be metered as liquid at such constant flow rate, and of such size that under normal operating conditions there will be a pressure drop at and beyond such second orifice means sufficient to cause at least substantial atomization and vaporization of the refrigerant before it enters the system being charged, a shut-off valve in said line, and a timer connected to control said shut-off valve and operative to open said valve for a predetermined time and thereby produce refrigerant flow at such constant flow rate for such predetermined time so as to deliver a measured quantity of refrigerant to the system being charged.

Claim 12

A servicing unit as in claim 7 in which said source of refrigerant is a closed container containing refrigerant in liquid state, pressurized by the vapor pressure of the refrigerant, so that the pressure varies with the temperature at which the container is maintained.

Claim 13

A servicing unit as in claim 7 in which the constant flow metering device comprises a cylinder having an inlet port at one end, a piston in the cylinder having a transverse wall and a cylindrical side wall, said piston and cylinder defining an inlet chamber communicating with the inlet port and a pressure chamber on the opposite side of the piston therefrom, a first orifice through the piston, leading from the inlet port to the pressure chamber, a second orifice through the wall of the cylinder, and an outlet to which said second orifice leads, the skirt of the piston being movable to partially close the second orifice as the piston moves in a direction away from the inlet port, and means for exerting a calibrated thrust on the piston to bias the same toward the inlet end of the cylinder, said first orifice being operable under flow conditions to cause a pressure drop across the piston and thereby urge the same against the said bias in a direction to close the second orifice and cause back-pressure in said pressure chamber, whereby to regulate the pressure drop across the first orifice.

Claim 14

A servicing unit as in claim 7 with the addition of a source of oil under pressure and a line containing a shut-off valve connecting said oil source to said constant flow metering device for delivery of oil therethrough to the system being charged, and an oil timer operable to open said shut-off valve for a predetermined time to allow oil to flow for such time at a constant rate through said metering device.

Claim 15

A servicing unit for air conditioning systems comprising a pressurized container of lubricating oil pressurized with nitrogen and arranged to deliver oil in liquid state, a charging line extending from said source and leading to a connector for connection to a charging fitting of the air conditioning system, said line containing a constant flow metering device adapted to pass the lubricating oil at a regulated rate, and control means including means for selectively predetermining the time period during which oil is delivered through said line and metering device to the system, and thereby to meter to the system a quantity of oil determined by said rate and the time.

Claim 16

A servicing unit for air conditioning systems comprising a pressurized container of lubricating oil pressurized with nitrogen and arranged to deliver oil in liquid state, a charging line extending from said source and leading to a connector for connection to a charging fitting of the air conditioning system, said line containing a constant flow metering device adapted to pass the lubricating oil at a regulated rate, and control means including means for selectively predetermining the time period during which oil is delivered through said line and metering device to the system, and thereby to meter to the system a quantity of oil determined by said rate and the time.