Bypass controller and bypass system
First Claim
1. In a system for providing conditioned air from a single HVAC unit to a plurality of zones through a duct system having a motor operated zone damper associated with each zone which modulates open and closed in response to a zone thermostat in each zone, the HVAC unit including a fan for discharging conditioned air into the outlet of the HVAC unit and a bypass duct communicating between the outlet and return air intake of the HVAC unit, a motor operated bypass damper, said bypass damper in said bypass duct having a damper blade movable between opened and closed positions and intermediate positions therebetween, the improvement comprising a programmable bypass controller connected to said motor of said bypass for controlling the operation of said bypass damper and thereby the movement of said blade thereof to selected positions, at least one said zone thermostat receiving information from each other said zone thermostat, said one thermostat communicating with said programmable bypass controller for selectively operating said bypass controller and its said damper in response to signals from said one thermostat, a sensor located in the air outlet of the HVAC unit downstream from said bypass duct and communicating with said bypass controller for providing information indicative of the air flow in said duct system, said bypass controller controlling said motor of said bypass damper to move its said damper blade more open to correspondingly compensate for the increase in the air flow in said duct system caused by one or more of said zone dampers modulating closed for diverting more air from the HVAC outlet to the HVAC inlet thereby maintaining the air supplied by the HVAC unit to said duct system downstream from said bypass dut generally constant.
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0 Petitions
Accused Products
Abstract
A microcomputer-controlled bypass controller for use in maintaining a minimum airflow through a heating/cooling unit and limit the static pressure in the supply air truck duct. The bypass controller functions to control the operation of a bypass damper which regulates the airflow through a duct that bypasses air from the supply truck duct to the return. The bypass controller also measures the air flow via an air flow sensor and communicates with a microcomputer-controlled thermostat to coordinate transitions between heating and cooling cycles in association with a second sensor which monitors the duct temperature.
125 Citations
21 Claims
- 1. In a system for providing conditioned air from a single HVAC unit to a plurality of zones through a duct system having a motor operated zone damper associated with each zone which modulates open and closed in response to a zone thermostat in each zone, the HVAC unit including a fan for discharging conditioned air into the outlet of the HVAC unit and a bypass duct communicating between the outlet and return air intake of the HVAC unit, a motor operated bypass damper, said bypass damper in said bypass duct having a damper blade movable between opened and closed positions and intermediate positions therebetween, the improvement comprising a programmable bypass controller connected to said motor of said bypass for controlling the operation of said bypass damper and thereby the movement of said blade thereof to selected positions, at least one said zone thermostat receiving information from each other said zone thermostat, said one thermostat communicating with said programmable bypass controller for selectively operating said bypass controller and its said damper in response to signals from said one thermostat, a sensor located in the air outlet of the HVAC unit downstream from said bypass duct and communicating with said bypass controller for providing information indicative of the air flow in said duct system, said bypass controller controlling said motor of said bypass damper to move its said damper blade more open to correspondingly compensate for the increase in the air flow in said duct system caused by one or more of said zone dampers modulating closed for diverting more air from the HVAC outlet to the HVAC inlet thereby maintaining the air supplied by the HVAC unit to said duct system downstream from said bypass dut generally constant.
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6. In a system for providing conditioned air from a single HVAC unit to a plurality of zones through a duct system having a motor operated zone damper associated with each zone which modulates open and closed in response to a zone thermostat in each zone, the HVAC unit including a fan for discharging conditioned air into the outlet of the HVAC unit and a bypass duct communicating between the outlet and return air intake of the HVAC unit, a motor operated bypass damper in said bypass duct having a damper blade movable between opened and closed positions and intermediate positions therebetween, the improvement comprising a programmable bypass controller including control means for operating said bypass damper, first circuit means responsive to input signals for establishing operating limits for said bypass damper and providing a first digital word output signal representative of said operating limits;
- second circuit means responsive to input signals indicative of the air flow in said system for providing a second digital word output signal representative of the air flow therein;
third circuit means adapted to be coupled to a peripheral circuit means for receiving data from a peripheral circuit means an for providing a third digital word output signal representative of the information contained in such data;
fourth circuit means responsive to output signals from said first, second, and third circuit means for providing fourth digital word output signals for operating said control means of said bypass damper;
programmable logic means for providing digital word input signals to said fourth circuit means for selectively controlling said fourth circuit means; and
logic means for selectively operating said bypass damper control means in response to respective said fourth digital word input signals from said fourth circuit means. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- second circuit means responsive to input signals indicative of the air flow in said system for providing a second digital word output signal representative of the air flow therein;
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17. A method of monitoring and controlling the amount of air recirculated through a bypass duct having a motor operated bypass damper therein between the supply and return ducts of a single HVAC unit supplying air downstream therefrom to a plurality of zones through a duct system having a motor operated damper in each zone controlled by a thermostat comprising the steps:
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a. sensing the airflow in the duct system downstream of the bypass duct, b. converting the sensed airflow into signals, c. supplying the signals to a microcomputer, and d. controlling from the microcomputer in conjunction with its programs and the signals supplied to the microcomputer in step c. of the bypass damper to divert more or less air through the bypass duct to maintain the airflow supplied by the HVAC unit to the duct system downstream of the bypass duct and prior to any outlets to any zones generally constant. - View Dependent Claims (18, 19)
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20. A method of changing modes from a heating mode to a cooling mode or from a cooling mode to a heating mode when monitoring and controlling the amount of air recirculated through a bypass duct having a bypass damper between the supply and return ducts of a single HVAC unit supplying air via the supply duct to a plurality of zones comprising the steps:
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a. determining that a first mode requirement of the HVAC unit has ended, b. determining that a second mode of the HVAC unit is required, c. positioning the bypass damper in the bypass duct full open until supply air temperature is generally in accord with the second mode, and d. moving the bypass damper to its selected positions during normal operation according to air flow requirements.
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21. A method of changing modes from a heating mode to a cooling mode or from a cooling mode to a heating mode when monitoring and controlling the amount of air recirculated through a bypass duct having a bypass damper between the supply and return ducts of a single HVAC unit supplying air via the supply duct to a plurality of zones through a duct system having a motor operated damper in each zone controlled by a thermostat comprising the steps:
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a. determining that a first mode requirement of the HVAC unit has ended, b. determining that a second mode of the HVAC unit is required, c. positioning the bypass damper in the bypass duct full open until supply air temperature is generally in accord with the second mode, d. maintaining all zone dampers in the first mode during step c., e. moving the bypass damper to its selected positions during normal operation according to air flow requirements, f. allowing all zone dampers to be positioned appropriately for the second mode when step e. has begun.
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Specification