초록 ▼

A multiple-boiler heating system is disclosed in which each boiler or stage is provided with an adjustable firing level of modulation at which the boiler is turned on and an adjustable threshold level of modulation (the MOD point), below which the next stage is disabled from being turned on. A contr

A multiple-boiler heating system is disclosed in which each boiler or stage is provided with an adjustable firing level of modulation at which the boiler is turned on and an adjustable threshold level of modulation (the MOD point), below which the next stage is disabled from being turned on. A control device for the heating system continuously compares temperature in the area being heated to the set point for the system and determines the total change in system output level (“DUTYCHANGE”) which would be required to produce a specified temperature within a predetermined time. Should DUTYCHANGE be negative, it is similarly distributed among the stages which are turned on. However, the reduction in modulation level proceeds backwards from the last stage which was turned on. When the last stage reaches its firing point, it is not turned off until the previous stage drops below its MOD point. The lead stage is turned off as soon as it reaches its firing point.

대표청구항 ▼

A boiler system for a medium to be heated, comprising: a plurality of boilers each having a control input for receiving a signal effective to regulate the modulation level of the boiler as a proportion of its fully turned-on condition; means for providing a sense signal representing the temperature

A boiler system for a medium to be heated, comprising: a plurality of boilers each having a control input for receiving a signal effective to regulate the modulation level of the boiler as a proportion of its fully turned-on condition; means for providing a sense signal representing the temperature or pressure of the medium; means for providing a set point signal representing the desired temperature or pressure of said medium; means jointly responsive to said sense and setpoint signals for generating a DUTYCHANGE signal representing the amount of energy required to change the temperature of said medium to said desired temperature or pressure within a predetermined time; and means for selecting one of said boilers as the lead boiler; sequencing means for producing a plurality of control signals, each applied to the control input of one of said boilers, said control signals being produced in a predefined sequence starting with the lead boiler\s control signal when the total output of all boilers is to be increased in the reverse of said predefined sequence, when the total output of all boilers is to be decreased; means defining for each boiler a FIRING point corresponding to the minimum modulation of the boiler when it is turned on and a MOD point corresponding to a modulation level of said boiler at which an immediately subsequent boiler is in said predefined sequence enabled to be turned on, and means for inhibiting a boiler from being brought below its firing point, before the preceding boiler is brought below its MOD point.