Temperature controller for controlling both heating and cooling

Claim 2

A temperature controller for a process comprising: means to maintain a measured temperature at a set point by controlling one of a pair of process inputs having opposite effects on said temperature, means responsive to a deviation between said measured temperature and said set point to produce an output from the controller operable to modify the magnitude of one of the inputs to the procees so as to tend to return said temperature to its set point, and means responsive only to the coincident occurrence of a magnitude for said one input below a preset value and a value for said deviation such that an increase in the other of said pair of inputs reduces the deviation, said last named means being operable to effect an increase in said other input to tend to reduce said deviation.

Claim 3

A process temperature controller comprising: means responsive to a signal representing the deviation from set point of a process temperature for producing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing a second gating signal when the effect of the control signal is to decrease the magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for introducing a cooling input to said process as long as said first and second gating signals are produced.

Claim 4

A process temperature controller comprising: means responsive to a signal representing the deviation from set point of a process temperature for producing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing a second gating signal when the effect of the control signal is to decrease the magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for introducing a cooling input to said process as long as said first and second gating signals are produced.

Claim 5

A process temperature controller as set forth in claim 2 in which the gating means includes a first and second switching element responsive to said first and second gating signals, respectively, and in which said switching elements upon actuation by said signals complete a series circuit for carrying a current which is effective to initiate the introduction of cooling to said process so that said cooling is continued until one of said gating signals disappears.

Claim 6

A process temperature controller as set forth in claim 2 in which said means for producing the control signal includes proportional and reset response to the deviation.

Claim 7

A process temperature controller comprising: means responsive to a signal representing the deviation from set point of a process temperature for produCing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing a second gating signal when the effect of the control signal is to decrease the magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for modifying a cooling input to said process so as to tend to reduce said deviation.

Claim 8

A process temperature controller comprising: means responsive to a signal representing the deviation from set point of a process temperature for produCing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing a second gating signal when the effect of the control signal is to decrease the magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for modifying a cooling input to said process so as to tend to reduce said deviation.

Claim 9

A process temperature controller comprising: control means responsive to both a signal representing the deviation from set point of a process temperature and a feedback signal representing the magnitude of the manipulated variable of the process for producing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing from said feedback signal a second gating signal when the feedback signal is of value to represent a magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for introducing a cooling input to said process as long as said first and second gating signals are produced.

Claim 10

A process temperature controller comprising: control means responsive to both a signal representing the deviation from set point of a process temperature and a feedback signal representing the magnitude of the manipulated variable of the process for producing a control signal operable to control the heat input to the process so as to tend to reduce said deviation, means responsive to said deviation signal for producing a first gating signal when said deviation indicates said temperature is higher than said set point, means for producing from said feedback signal a second gating signal when the feedback signal is of value to represent a magnitude of the manipulated variable below a preset value, and gating means responsive to the coincidence of said first and second gating signals for introducing a cooling input to said process as long as said first and second gating signals are produced.

Claim 11

A temperature control system for a process comprising: a heating input to the process, a cooling input to the process, means for measuring that temperature in the process which is to be controlled, means for establishing a set point value for said temperature, means responsive to the difference between the said measured temperature and said set point to produce a control output operable to modify the magnitude of one of the inputs to the process so as to tend to return said temperature to its set point, and means responsive only to the coincident occurrence of a magnitude for said one input which is below a preset value and a value for said difference such that an increase in said other input would be effective to reduce said difference, said last named means being operable to effect a change in said other input to tend to reduce said deviation.

Claim 12

A temperature control system for a process comprising: a heating input to the process, a cooling input to the process, means for measuring that temperature in the process which is to be controlled, means for establishing a set point value for said temperature, means responsive to the difference between the said measured temperature and said set point to produce a control output operable to modify the magnitude of one of the inputs to the process so as to tend to return said temperature to its set point, and means responsive only to the coincident occurrence of a magnitude for said one input which is below a preset value and a value for said difference such that an increase in said other input would be effective to reduce said difference, said last named means being operable to effect a change in said other input to tend to reduce said deviation.