Centrifugal heat pump with overload protection

Claim 2

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down, and a means of limiting the effective pumping head of the said vapor compression means for a period of time when starting the vapor compression means after its having been stopped so that overloading of the said vapor compression means can be avoided, and means of controlling the said period of time.

Claim 3

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sEnsitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down, and a means of limiting the effective pumping head of the said vapor compression means for a period of time when starting the vapor compression means after its having been stopped so that overloading of the said vapor compression means can be avoided, and means of controlling the said period of time.

Claim 4

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sEnsitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down, and a means of limiting the effective pumping head of the said vapor compression means for a period of time when starting the vapor compression means after its having been stopped so that overloading of the said vapor compression means can be avoided, and means of controlling the said period of time.

Claim 5

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down, and a means of controlling the temperature of said evaporating means and the said condensing means towards establishing suitable operating temperatures in these evaporating and condensing means, when starting the said heat pump after its having been stopped, to avoid overloading of the said compression means.

Claim 6

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down, and a means of controlling the temperature of said evaporating means and the said condensing means towards establishing suitable operating temperatures in these evaporating and condensing means, when starting the said heat pump after its having been stopped, to avoid overloading of the said compression means.

Claim 7

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down, and a means of controlling the temperature of the said evaporating means and the said condensing means towards establishing suitable operating temperatures in these evaporating and condensing means, when starting the said cooling system after its having been stopped, to avoid overloading of The said compression means.

Claim 8

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down, and a means of controlling the temperature of the said evaporating means and the said condensing means towards establishing suitable operating temperatures in these evaporating and condensing means, when starting the said cooling system after its having been stopped, to avoid overloading of The said compression means.

Claim 9

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down, and a means of removing any refrigerant in liquid form from the said evaporating means after the said compression means has been called to stop, and means of gradually re-introducing the said refrigerant in liquid form into the said evaporating means after the said compression means has re-started, to avoid overloading of the said compression means.

Claim 10

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be undesirably low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down, and a means of removing any refrigerant in liquid form from the said evaporating means after the said compression means has been called to stop, and means of gradually re-introducing the said refrigerant in liquid form into the said evaporating means after the said compression means has re-started, to avoid overloading of the said compression means.

Claim 11

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down and a means of removing any refrigerant in liquid form from the said evaporating means after the said compression means has been called to stop, and means of gradually re-introducing the said refrigerant in liquid form into the said evaporating means after the said compression means has re-started, to avoid overloading of the said compression means.

Claim 12

In combination a variable capacity cooling system used for cooling an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machinery in such a manner to provide a variable frequency flux through the said windings, and thus achieve a variable speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive only to the refrigerant vapor pressure in the said evaporator, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said evaporator to be undesirably high the compressor is speeded up till a suitable evaporator pressure is reached and similarly when the evaporator pressure is too low the compressor is slowed down and a means of removing any refrigerant in liquid form from the said evaporating means after the said compression means has been called to stop, and means of gradually re-introducing the said refrigerant in liquid form into the said evaporating means after the said compression means has re-started, to avoid overloading of the said compression means.

Claim 13

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machiNery in such a manner to provide a variable frequency flux through the said windings, and thus achieve speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down and in this manner a predetermined condenser pressure level is maintained, and a means of determining the said predetermined condenser pressure which means is sensitive to the outdoor air temperature, so that higher condenser pressure levels are maintained at low outdoor air temperatures and lower condenser pressure levels are maintained at higher outdoor air temperatures.

Claim 14

In combination a variable capacity heat pump used for heating an air filled space and comprising kinetic displacement vapor compression means direct driven by variable speed, alternating current, electric motor machinery of the squirrel-cage induction type and the said compression means and motor machinery being combined in a common hermetic enclosure, to pump refrigerant vapor from a refrigerant evaporating means to a condensing means, a variable frequency inverter means using sequential switching equipment to switch electrical current from an external source into the windings of the said motor machiNery in such a manner to provide a variable frequency flux through the said windings, and thus achieve speed rotation of the said motor machinery, since the rotation speed of this type of motor is dependent on the frequency of the current supplied to it, a pressure sensing means which is sensitive to the refrigerant vapor pressure in the said condenser, and the frequency of the said variable frequency inverter is controlled by this said pressure sensing means so that when operating conditions cause the pressure in the said condenser to be low the compressor is speeded up till a suitable condenser pressure is reached and similarly when the condenser pressure is too high the compressor is slowed down and in this manner a predetermined condenser pressure level is maintained, and a means of determining the said predetermined condenser pressure which means is sensitive to the outdoor air temperature, so that higher condenser pressure levels are maintained at low outdoor air temperatures and lower condenser pressure levels are maintained at higher outdoor air temperatures.