Patents by Inventor David M Christensen

David M Christensen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11156383
    Abstract: A heater having a burner, a first heat exchanger associated with the burner, a second heat exchanger above the first heat exchanger in fluid cooperation with the first heat exchanger and an ambient air intake blower above the second heat exchanger. The second heat exchanger comprises angularly disposed finned section so condensate within the second heat exchanger flows to a collection point and is collected in a trap. The trap includes a sensor to sense buildup of fluid in the trap with feedback to the heater controls. The heater may include a collection pan below the heat exchangers in fluid communication with the trap. In one aspect the collection pan may include a heating element to vaporize the fluid so that heated, humidified air is expelled through vents adjacent the base of the heater. In another aspect, the pan includes an ultrasonic vaporization element to vaporize fluid in the pan.
    Type: Grant
    Filed: July 18, 2018
    Date of Patent: October 26, 2021
    Assignee: Empire Comfort Systems, Inc.
    Inventors: Bruce Dresner, David M. Christensen, Scott G. Schulte
  • Publication number: 20180320928
    Abstract: A heater having a burner, a first heat exchanger associated with the burner, a second heat exchanger above the first heat exchanger in fluid cooperation with the first heat exchanger and an ambient air intake blower above the second heat exchanger. The second heat exchanger comprises angularly disposed finned section so condensate within the second heat exchanger flows to a collection point and is collected in a trap. The trap includes a sensor to sense buildup of fluid in the trap with feedback to the heater controls. The heater may include a collection pan below the heat exchangers in fluid communication with the trap. In one aspect the collection pan may include a heating element to vaporize the fluid so that heated, humidified air is expelled through vents adjacent the base of the heater. In another aspect, the pan includes an ultrasonic vaporization element to vaporize fluid in the pan.
    Type: Application
    Filed: July 18, 2018
    Publication date: November 8, 2018
    Inventors: Bruce Dresner, David M. Christensen, Scott G. Schulte
  • Patent number: 10072872
    Abstract: A heater having a burner, a first heat exchanger associated with the burner, a second heat exchanger above the first heat exchanger in fluid cooperation with the first heat exchanger and an ambient air intake blower above the second heat exchanger. The second heat exchanger comprises angularly disposed finned section so condensate within the second heat exchanger flows to a collection point and is collected in a trap. The trap includes a sensor to sense buildup of fluid in the trap with feedback to the heater controls. The heater may include a collection pan below the heat exchangers in fluid communication with the trap. In one aspect the collection pan may include a heating element to vaporize the fluid so that heated, humidified air is expelled through vents adjacent the base of the heater. In another aspect, the pan includes an ultrasonic vaporization element to vaporize fluid in the pan.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: September 11, 2018
    Assignee: Empire Comfort Systems, Inc.
    Inventors: Bruce Dresner, David M. Christensen, Scott G. Schulte
  • Publication number: 20150369518
    Abstract: A heater having a burner, a first heat exchanger associated with the burner, a second heat exchanger above the first heat exchanger in fluid cooperation with the first heat exchanger and an ambient air intake blower above the second heat exchanger. The second heat exchanger comprises angularly disposed finned section so condensate within the second heat exchanger flows to a collection point and is collected in a trap. The trap includes a sensor to sense buildup of fluid in the trap with feedback to the heater controls. The heater may include a collection pan below the heat exchangers in fluid communication with the trap. In one aspect the collection pan may include a heating element to vaporize the fluid so that heated, humidified air is expelled through vents adjacent the base of the heater. In another aspect, the pan includes an ultrasonic vaporization element to vaporize fluid in the pan.
    Type: Application
    Filed: November 25, 2013
    Publication date: December 24, 2015
    Inventors: Bruce Dresner, David M. Christensen, Scott G. Schulte
  • Patent number: 9062881
    Abstract: A fuel burning space or zone heating appliance or heater rated or decorative fireplace (hearth appliance) and a method of operating a heater including a gas valve, a pressure transducer, a second pressure measurement device, a combustion fan, and a control. The control compares the signal from the pressure transducer to the signal from the second pressure measurement device. If the signals do not sufficiently correspond, the control prevents the gas valve from opening. If the signals sufficiently correspond, the control performs an ignition sequence and opens the gas valve. The control also compares the signal from the pressure transducer to a desired value based on a current input gas rate through the gas valve. If the signal is greater than the desired value, the control decreases power to the combustion fan. If the signal is less than the desired value, the control increases power to the combustion fan. If the signal is less than the desired value, the control turns the gas valve off to cease ignition.
    Type: Grant
    Filed: February 19, 2013
    Date of Patent: June 23, 2015
    Assignee: Empire Comfort Systems, Inc.
    Inventors: Bruce Dresner, Frank D. Wurth, David M. Christensen
  • Publication number: 20130255664
    Abstract: A heater having an evaporating and humidifying apparatus therein, the evaporating and humidifying apparatus comprising a fluid pan with a heating element. In one aspect, the pan is in fluid communication with a condensate trap assembly. In one aspect the apparatus can include a base pan, the heating element, an insulator and an evaporation pan above the heating element. The evaporating and humidifying apparatus can include a fluid level sensor operatively associated with the heater controls. The condensate trap assembly may include a fluid level sensor operatively associated with the heater controls to determine fluid levels in the trap assembly. In one aspect the pan comprises an ultrasonic vaporization element in lieu of a heating element.
    Type: Application
    Filed: March 27, 2013
    Publication date: October 3, 2013
    Applicant: EMPIRE COMFORT SYSTEMS, INC.
    Inventors: Bruce Dresner, David M. Christensen, Scott G. Schulte
  • Publication number: 20130216962
    Abstract: A fuel burning space or zone heating appliance or heater rated or decorative fireplace (hearth appliance) and a method of operating a heater including a gas valve, a pressure transducer, a second pressure measurement device, a combustion fan, and a control. The control compares the signal from the pressure transducer to the signal from the second pressure measurement device. If the signals do not sufficiently correspond, the control prevents the gas valve from opening. If the signals sufficiently correspond, the control performs an ignition sequence and opens the gas valve. The control also compares the signal from the pressure transducer to a desired value based on a current input gas rate through the gas valve. If the signal is greater than the desired value, the control decreases power to the combustion fan. If the signal is less than the desired value, the control increases power to the combustion fan. If the signal is less than the desired value, the control turns the gas valve off to cease ignition.
    Type: Application
    Filed: February 19, 2013
    Publication date: August 22, 2013
    Applicant: Empire Comfort Systems, Inc.
    Inventors: Bruce Dresner, Frank D. Wurth, David M. Christensen
  • Patent number: 7438185
    Abstract: The invention concerns a tray having an integral latch that mates to a boss of an adjacent tray to form a stable stack. The latch may be incorporated into any type of tray, basket, or other container for storing articles. Multiple containers may be stacked together without the use of a detachable clip. Also disclosed is a tray that includes an array of posts extending downward to support the tray on a flat surface.
    Type: Grant
    Filed: May 17, 2005
    Date of Patent: October 21, 2008
    Assignee: Peak Plastic and Metal Products (International) Limited
    Inventors: Thi Q. Ho, David M. Christensen
  • Patent number: 7299927
    Abstract: A wafer container comprising a base and a cover that nest together. The cover includes tabs on a lower portion that engage notches on the frame. The cover can be combined with the base without indexing to a precise opening on the frame. A handle on the cover enables an operator to easily rotate the container into a locked position. A ribbed pattern on the exterior surface of the frame enables the wafer container to be stacked with another wafer container.
    Type: Grant
    Filed: February 7, 2005
    Date of Patent: November 27, 2007
    Assignee: Peak Plastic & Metal Products (International) Limited
    Inventors: Steven R. Emter, David M. Christensen
  • Patent number: 6945160
    Abstract: A cooker and smoker apparatus for an outdoor grill is comprised of a plurality of louvers that are pivoted between a first position where the louvers overlap each other and a second position where the louvers are oriented uprightly relative to each other for the respective indirect and direct cooking of food supported on a cooking grate of the outdoor grill. The cooker and smoker apparatus provides for smoking of the cooking food in both modes of operation. Additionally, the cooker and smoker apparatus is provided with a simplified construction that reduces the cost of its manufacturing and enables the apparatus to be a part of an outdoor grill as it is manufactured or to be retrofit to an existing outdoor grill.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: September 20, 2005
    Assignee: Empire Comfort Systems, Inc.
    Inventors: David M. Christensen, Bernard A. Lauzon, Daniel J. Sovar, John A. Schweiss
  • Publication number: 20040094142
    Abstract: A cooker and smoker apparatus for an outdoor grill is comprised of a plurality of louvers that are pivoted between a first position where the louvers overlap each other and a second position where the louvers are oriented uprightly relative to each other for the respective indirect and direct cooking of food supported on a cooking grate of the outdoor grill. The cooker and smoker apparatus provides for smoking of the cooking food in both modes of operation. Additionally, the cooker and smoker apparatus is provided with a simplified construction that reduces the cost of its manufacturing and enables the apparatus to be a part of an outdoor grill as it is manufactured or to be retrofit to an existing outdoor grill.
    Type: Application
    Filed: November 14, 2002
    Publication date: May 20, 2004
    Inventors: David M. Christensen, Bernard A. Lauzon, Daniel J. Sovar, John A. Schweiss
  • Patent number: 6463926
    Abstract: A direct vent gas fireplace has an angled flue pipe that can be directed horizontally out of the back of the fireplace or vertically out of the top of the fireplace, a baffle that conceals an exhaust opening in the back of the fireplace heat chamber from view while minimizing shielding of the firebox panels surrounding the fireplace heat chamber, and an air column that directly channels venting air from the flue pipe downwardly across the back panel of the firebox to an air inlet adjacent to the bottom of the firebox.
    Type: Grant
    Filed: June 9, 2000
    Date of Patent: October 15, 2002
    Assignee: American Hearth Systems, Inc.
    Inventors: Christopher L. Flick, Corbit Beasey, David M. Christensen, Robert B. Zahm
  • Patent number: 6314868
    Abstract: The present invention pertains to an outdoor cooker or barbeque that cooks food by providing direct or indirect heat from a heat source of the cooker to the food. The outdoor cooker has a gas or charcoal heat source that provides direct and indirect heat to foods supported on a cooking surface of the grill by operation of a plurality of parallel louvers between the heat source and grill that are moved between first, upright positions of the louvers that provide direct heating of the food and second, angled relative positions of the louvers that provide indirect heating of the food.
    Type: Grant
    Filed: March 27, 2001
    Date of Patent: November 13, 2001
    Assignee: Empire Comfort Systems, Inc.
    Inventors: David M. Christensen, John A. Hart, Wayne E. Thuenemann
  • Patent number: 6269737
    Abstract: A cooking apparatus includes a container, a spigot, a lid, and a food support. The container has a bottom surface and a side wall that extends upwardly from the bottom surface to a top edge of the side wall. The spigot is attached to the container side wall and has a valve member that is selectively positionable between opened and closed positions. The spigot valve member allows liquid contents of the container to drain from the container when in the opened position, and prevents the contents from draining out of the container when in the closed position. The food support is comprised of a perforated horizontal member with a perforated side wall extending upwardly from the horizontal member. A plurality of vertical members spaced around the periphery of the horizontal member extend upwardly from the horizontal member.
    Type: Grant
    Filed: June 14, 2000
    Date of Patent: August 7, 2001
    Assignee: Empire Comfort Systems, Inc.
    Inventors: Donald P. Rigney, David M. Christensen
  • Patent number: 6173843
    Abstract: A spring-biased latching mechanism eliminates the use of brackets and screws to retain expansion cards or electronic circuit boards in computers or similar information handling systems. The spring-biased latching mechanism has a latching member that is cammed out of the path of a computer expansion card as the card is inserted into the computer housing; the latching or retention member may be pushed to a fully retracted or withdrawn position and latched, thus removing the latching member from interference with the expansion card and permitting easy removal of the expansion card. The spring-biased latching member is provided with a groove to provide guidance to the expansion card during insertion and may stabilize the card whenever the latching member is extended to retain the expansion card in position relative to a computer motherboard.
    Type: Grant
    Filed: November 15, 1999
    Date of Patent: January 16, 2001
    Assignee: Gateway, Inc
    Inventors: David M Christensen, Arthur L. Smith
  • Patent number: 5337590
    Abstract: Method and apparatus for bending serpentine heat exchanger tubes using a split bend die having a relatively short upper die section with a straight back end. After the tube is bent in conventional manner using a clamp die and a pressure die, the bend die is split along a shaft and rotated through a predetermined angle to position the straight back end substantially parallel to a straight segment of the tube at the output of the bend die. The input segment of the tube is then moved next to the shaft in preparation for rotating above the input segment to raise the output segment above the upper section of the bend die. Such lateral motion reduces the segment spacing required for clearance of the upper section. Other features for reducing the spacing are providing an indentation on the shaft, angling the back end with respect to the sides to provide a minimum length, and truncation an upper portion along the back end.
    Type: Grant
    Filed: December 27, 1993
    Date of Patent: August 16, 1994
    Inventors: Eugene H. Schuchert, David M. Christensen, Samuel B. McGuire
  • Patent number: 5284041
    Abstract: Method and apparatus for bending metal tubes such as for furnace heat exchangers. After the bend die is rotated 180.degree. to make a bend, an upper section of the bend die is split from a lower section, and the upper section is then rotated approximately 90.degree.. In such manner, a portion of the upper section is displaced laterally to vacate a region directly above the lower section. Therefore, in moving the tube forwardly to a new location for a subsequent bend operation, a portion of a previous bend passes through the vacated region thereby enabling sequential bend angles that are less restricted than without rotating the upper section of the split die.
    Type: Grant
    Filed: May 10, 1993
    Date of Patent: February 8, 1994
    Assignee: Amana Refrigeration, Inc.
    Inventors: David M. Christensen, Eugene H. Schuchert, Richard N. Walker
  • Patent number: 4970870
    Abstract: An input command system for an electronic refrigerator control wherein dedicated function keys are provided for inputting commands to the processor. The processor will not accept inputs from the dedicated function keys unless an enable key is pressed first. The enable key is hidden on the control panel so as to avoid unauthorized inputting of commands. Once enabled, the processor receives commands for a predetermined time period that is extended when commands are input.
    Type: Grant
    Filed: November 6, 1989
    Date of Patent: November 20, 1990
    Assignee: Amana Refrigeration, Inc.
    Inventors: Brian M. Midlang, David M. Christensen