Flow control system

A differential pressure sensor comprised of:

• a housing having first and second spaced apart fluid chamber connectable respectively to first and second fluid pressure sources to be monitored,
• a pressure responsive assembly within said housing comprised of first and second pressure sensitive members connected to one another, said first pressure sensitive member being exposed to said first fluid chamber and said second pressure sensitive member being exposed to said second chamber, said pressure responsive assembly mounted to said housing wherein said assembly is moveable along a fixed axis in response to differences in fluid pressure in said first and said second chambers,
• an element attached to said pressure responsive assembly for movement therewith, said element disposed between said first and said second pressure sensitive elements and external to said first and said second chambers, and
• a non-contacting sensor mounted to said housing adjacent to said element, said sensor being responsive to movement of said element and providing a series of pulses having a frequency indicative of the position of said element.

A differential pressure sensor comprised of:

• a housing having first and second spaced apart fluid chambers connectable respectively to first and second fluid pressure sources to be monitored, said housing comprised of a plurality of housing sections which are crimped together,
• a pressure responsive assembly within said housing comprised of first and second pressure sensitive members connected to one another, said first pressure sensitive member begin exposed to said first fluid chamber and said second pressure sensitive member being exposed to said second chamber, said pressure responsive assembly mounted to said housing wherein said assembly is movable along a fixed axis in response to differences in fluid pressure in said first and said second chambers,
• an element attached to said pressure responsive assembly for movement therewithin, said element disposed between said first and said second pressure sensitive elements and external to said first and said second chambers, and
• a non-contacting sensor mounted to said housing adjacent to said element, said sensor being responsive to movement to said element and providing electrical signals indication of the position of said element.

In a combustion heating system having a heat exchanger, a variable speed inducer motor for creating flow along a path including said heat exchanger, and a transducer for measuring a pressure differential along said path, a method of operating said system comprising the steps of:

• establishing a plurality of system operating modes, each of said system operating modes having a predetermined optimum pressure differential value;
• sensing a measured pressure differential across the heat exchanger;
• providing a first and second series of pulses having a first frequency and second frequency respectively, said first and second frequencies related to the measured pressure differential;
• determining a first and second time to count the same number of pulses of each first and second series of pulses respectively;
• converting said first and second time into an indication of the measured pressure differential;
• computing a deviation between the indication of measured pressure differential and the predetermined optimum pressure differential value;
• and
• varying the velocity of the variable speed inducer motor in accordance with said deviation.

A controller for regulating a combustion flow rate along a path in a combustion system having a heat exchanger and a variable speed inducer motor, said controller comprising:

• means for establishing a plurality of operating modes;
• means for storing a predetermined optimum pressure differential value for each said operating mode;
• sensing means for sensing a measured pressure differential between two locations along said path and for providing a series of pulses having a frequency related to the measured pressure differential;
• means for determining a time to count a predetermined number of said pulses and for converting said time into an indication of the measured pressure differential;
• calculation means for calculating a deviation between the indication of measured pressure differential and the predetermined optimum pressure differential value;
• and
• means for varying the velocity of the variable speed inducer motor in accordance with the deviation.

A heating apparatus including:

• a combustion air inlet,
• a combustion means for receiving a flow of combustion air and for burning a mixture of combustion air and combustible fluid to produce a combusted fluid air mixture,
• a heat exchanger means defining a path for a flow of combusted fluid air mixture therethrough,
• a motor-driven means for creating a flow of the combustion air through said combustion means and for providing a flow of the combusted fluid air mixture along said path through said heat exchanger means,
• a differential pressure transducer means for determining a difference in pressure between two positions along said path and for providing a series of pulses having a frequency related to said difference in pressure;
• a microprocessor control system comprising:
• means for converting the series of pulses into an indication of the difference in pressure;
• means for storing at least one predetermined pressure differential value;
• means for determining a deviation between the indication of difference in pressure and the at least one predetermined pressure differential value;
• and
• means operatively connected to said variable motor-driven means for adjusting the difference in pressure between the two positions along said heat exchanger in accordance with said deviation.

A control system for monitoring and adjusting a pressure differential value across a fluid flow chamber, said control system comprising:

• differential sensor means for sensing a first measured pressure at a first location along the fluid flow chamber and a second measured pressure at a second location along the fluid flow chamber, and providing a series of pulses having a frequency related to the pressure differential value;
• means for determining a time to count a predetermined number of said series of pulses and for converting said time into an indication of the measured pressure differential value;
• calculation means for calculating a deviation between the indication of measured pressure differential value and a predetermined pressure differential value;
• and
• means for changing the pressure differential value in accordance with said deviation.

A controller for regulating a combusted fluid flow rate in a combustion system having a heat exchanger, a variable speed inducer motor, a variable gas flow regulator, said controller comprising:

• means for storing a gas pressure differential value and a corresponding air pressure differential value, for a plurality of heat demand values;
• first sensing means for sensing a first measured pressure differential across the heat exchanger and for providing series of pulses having a frequency related to the first measured pressure differential,
• means for determining a time to count a predetermined number of said series of pulses and for converting said time into a indication of the first measured pressure differential;
• second sensing means for sensing a second measured pressure differential across the variable gas flow regulator and for providing a second signal output that is related thereto;
• calculation means for calculating a first deviation between the indication of first measured pressure differential and the stored air pressure differential value and a second deviation between the second signal output and the stored gas pressure differential value;
• and
• means for changing the combustion flow rate in accordance with said first and second deviations.

A controller for regulating a flow rate of a heat transfer fluid for maximum efficiency, said controller comprising;

• means for storing a first flow rate parameter and a corresponding second flow rate parameter, for a plurality of heat transfer parameters;
• first sensing means for indicating a first flow rate along a first path and for providing a series of pulses having a frequency related to said first flow rate;
• processor means for counting a predetermined number of said series of pulses and for determining an interval of time required to count the same, said processor means converting said interval of time into an indication of the first flow rate;
• second sensing means for indicating a second flow rate along a second path and for providing a signal output related thereto, said processor means determining from said signal output an indication of the second flow rate
• comparison means for comparing said indication of first flow rate to said stored first flow rate parameter and for comparing said indication of second flow rate to said stored second flow rate parameter for a particular heat transfer parameter;
• and
• means for changing the flow rate of the heat transfer fluid in response to said comparison.

A controller for regulating a flow rate of a heat transfer fluid in a heat transfer system, said heat transfer system having a heat transfer fluid flow path, means for creating flow along said path, an air flow path, air flow regulator, a fuel flow path, and a fuel flow regulator, said controller comprising:

• means for storing a predetermined fuel pressure differential and a corresponding predetermined heat transfer fluid pressure differential, for a plurality of heat demand values,
• first sensing means adapted to measure fuel pressure differential along the fuel flow path at said fuel source and for providing a first output signal indicative thereof;
• second sensing means for sensing a measured heat transfer fluid pressure differential along the heat transfer fluid flow path and for providing a series of pulses having a frequency related thereto;
• means for converting the first output into an indication of the fuel pressure differential and for converting the series of pulses into an indication of the heat transfer fluid pressure differential;
• comparison means for comparing said predetermined fuel pressure differential to said indication of fuel pressure differential and for comparing said predetermined heat transfer fluid pressure differential to said indication of heat transfer fluid pressure differential;
• and
• means for regulating said air flow regulator and said fuel flow regulator in response to said comparison means.

A control system for regulating the flow rate of a heat transfer fluid in a heat transfer system, said heat transfer system having a heat transfer fluid flow path, flow control means for creating flow along said path, a fuel source for providing a combustible fuel to said path, an air source for providing combustion air to said path, and means for combusting said fuel and air to create said heat transfer fluid, said control system comprising:

• means for storing a fuel flow value and a corresponding air flow value for a plurality of heat transfer values;
• first sensing means for sensing a measured flow value at said fuel source and providing a first signal output related thereto;
• second sensing means for sensing a measured flow value at said air source and providing a series of pulses having a frequency related thereto;
• means for determining a time to count a predetermined number of pulses and for converting said time into an indication of the flow value at said air source, said determining means converting said first signal output into an indication of the flow value at said fuel source;
• comparison means for comparing said stored fuel flow value to said indication of flow value at said fuel source, and for comparing said stored air flow value to said indication of flow value at said air source;
• fuel regulating means for regulating said fuel flow at said fuel source;
• and
• means for adjusting said fuel regulating means and said flow control means in response to said comparison means.

A control system for regulating the flow rate of a heat transfer fluid in a heat transfer system, said heat transfer system having a heat transfer fluid flow path, flow control means for creating flow along said path, a fuel source for providing a combustible fuel to said path, an air source for providing combustion air to said path, and means for combusting said fuel and air to create said heat transfer fluid, said control system comprising:

• sensing means for sensing a measured flow value at said air source and for producing a series of pulses having a frequency related to said sensed flow value;
• means for determining an interval of time to count a predetermined number of pulses from said series of pulses and for converting said interval of time into an indication of the measured flow value;
• means for storing an optimum flow value at said air source;
• means for storing a range of operating control values for said flow control means, said operating control values corresponding to said optimum flow value;
• calculation means for calculating a deviation between said indication of measured flow value and said optimum flow value;
• and
• means for varying the operation of said flow control means in accordance with said deviation.

A heating apparatus including:

• a combustion air inlet,
• a combustion means for receiving a flow of combustion air and for burning a mixture of combustion air and combustible fluid to produce a combusted fluid air mixture,
• a heat exchanger means defining a path for a flow of combusted fluid air mixture therethrough,
• a flow device for creating a flow of the combustion air through said combustion means and for providing a flow of the combusted fluid air mixture along said path through said heat exchanger means,
• an SR motor for driving said flow device,
• a differential pressure transducer for determining a pressure value at two positions along said path and providing a series of pulses having a frequency related to the pressure values,
• a microprocessor control system for controlling said SR motor, said control system determining a time to count a predetermined number of said series of pulses and for converting said time into an indication of the measured pressure differential, said control system monitoring any deviation between the indication of the measured pressure differential value provided by the continuous differential pressure transducer means and a predetermined pressure differential value, and adjusting the speed of said SR motor in response thereto.