Patent Publication Number: US-2011070818-A1

Title: Air blower validator, an hvac system and a method of manufacturing an hvac system

Description:
TECHNICAL FIELD 
     This application is directed, in general, to heating, ventilating and air conditioning (HVAC) systems, and more specifically, to air blower fans of HVAC systems. 
     BACKGROUND 
     In an HVAC system, an air blower is used to circulate air through an enclosure and the HVAC system. Typically, the air blower is used to pull air from the enclosure into the HVAC system through ducts and push the air back into the enclosure through additional ducts after conditioning the air (e.g., heating or cooling the air). To insure that the air blower is working properly, a system controller (e.g., a processor) is often used to monitor the operation of the air blower. One way of monitoring the air blower is by using an electrical switch to confirm if the motor is operating or not operating. Additionally, a pressure sensor may be used to determine if air is being moved by the air blower. 
     SUMMARY 
     In one aspect, an air blower validator for an HVAC system is disclosed. In one embodiment, the air blower validator includes: (1) a air pressure detector including a first pressure port configured to receive air from inside an air blower housing of an HVAC system and (2) an air collector configured to deliver the air to the first pressure port, the air collector including a pressure tap configured to couple to an opening in the air blower housing. 
     In another aspect, a method of manufacturing an HVAC system is disclosed. In one embodiment the method includes: (1) positioning a pressure tap of the air collector at a location of a housing of an air blower to capture air pressure in the air blower housing and (2) coupling the pressure tap to an opening at the location, wherein the pressure tap is coupled to a first pressure port of the air pressure detector. 
     In yet another aspect, an HVAC system is disclosed. In one embodiment, the HVAC system includes: (1) an air blower having an air blower housing and configured to circulate air through the HVAC system and (2) an air blower validator coupled to HVAC system, having: (2A) an air pressure detector including a first pressure port configured to receive the air from inside the air blower housing and (2B) an air collector configured deliver the air to the first pressure port, the air collector including a pressure tap configured to couple to an opening in the air blower housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A  illustrates a block diagram of an embodiment of an HVAC system constructed according to the principles of the disclosure; 
         FIG. 1B  illustrates a diagram of an air blower with an embodiment of an air blower validator constructed according to the principles of the present disclosure; 
         FIG. 2  illustrates a block diagram of one embodiment of an air blower validator constructed according to the principles of the disclosure; and 
         FIG. 3  illustrates a flow diagram of an embodiment of a method of manufacturing a HVAC system carried out according to the principles of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Employing pressure sensors to monitor the operation of an air blower can be expensive due to the sensitivity needed to measure the changes of air pressure. This can be especially true when variable speed motors are employed due to the small changes in air pressure between the various speeds. Typically, a more sensitive (and often more expensive) pressure sensor may be needed to detect air pressure changes at these low flow conditions. Thus, improvements in determining if an air blower is operating properly, i.e., moving air, can be advantageous. 
     This disclosure provides a proving device for an air blower that is connected to the housing of an air blower. The proving device, an air blower validator, includes an air collector coupled to a supply port or supply ports of an air pressure detector and configured to deliver air from within the housing of the air blower to the supply port or ports to allow detection of static pressure, total pressure or velocity pressure from the air blower. The air collector may include multiple sections. For example, the air collector may include a pressure tap and a supply conduit that couples the pressure tap to the supply port of the air pressure detector. The pressure tap may be coupled to an opening of the air blower housing and may extend through the air blower housing opening with an opening that faces air flow generated by the air blower. The supply conduit delivers air captured by the pressure tap to the supply port. The supply conduit may be external to the air blower housing. In some embodiments, the air collector may include a single section, the pressure tap. In these embodiments, the pressure tap may have one end that is coupled to the supply port and an angled-end that extends into the air blower housing and configured to capture total pressure, including velocity pressure, from the air blower housing. The air collector may include multiple pressure taps and supply conduits. 
     The pressure tap of the air collector may be positioned to capture a maximum total pressure or at least substantially the maximum total air pressure reading in the air blower housing. The mounting location for capturing maximum total air pressure may be determined by experimentation or theoretical calculation. (See, for example, “FANS,” by Theodore Baumeister, Jr., Mcgraw Hill Book Company Inc., 1935, pages 100-110). The location may vary for different air blower models. In some embodiments, utilizing radially or axially expanding blower designs, the location may be between 180-230 degrees from the cut-off section of the air blower. 
     By locating the pressure tap as disclosed in one of the embodiments herein, the air pressure detector may capture the added benefit of velocity pressure (e.g., 0.3″ water column (wc) or higher) that makes a total pressure reading reasonably above the operating settings of the air pressure detector. Thus, the air blower validator can be used repeatedly and reliably to monitor the operation of an air blower. This is especially useful for variable speed blowers operating at low flow conditions when changes in the total air pressure are difficult to detect. 
       FIG. 1A  is a schematic diagram of an embodiment of an 
     HVAC system  100  constructed according to the principles of the present invention. The HVAC system  100  includes a return duct  110 , a return plenum  115 , an air blower  120 , a supply plenum  130 , a supply duct  140 , a controller  150  and an air blower validator  160 . One skilled in the art will understand that HVAC system  100  may include additional components and devices that are not presently illustrated or discussed but are typically included in an HVAC system, such as, cooling coils and heating elements. A thermostat (not shown) is also typically employed with a HVAC system  100  and used as a user interface. 
     The air blower  120  is configured to circulate air through an enclosure (not shown) by suctioning air from the enclosure through the return duct  110  and the return plenum  115 , as indicated by arrow  112 , and discharging air to the enclosure, as indicated by arrow  132  through the supply plenum  130  and the supply duct  140 . The supply plenum  130  is in fluid communication with the supply duct  140  to supply discharged air to the enclosure. The air blower  120  may be a conventional blower used in HVAC systems to circulate air through an enclosure. In some embodiments, the air blower  120  may include a variable speed motor and operate at various speeds. The air blower  120  has a housing  122  that includes, for example, a blower motor and wheel (not illustrated). 
     Operation of the air blower  120  may be controlled by the controller  150  based on inputs from, for example a thermostat. The controller  150  may be a processor, such as a microprocessor, configured to direct the operation of the HVAC system  100 . As illustrated in  FIG. 1 , the controller  150  may be coupled to the air blower validator  160  through a wired-connection. A cable may be used to couple the controller  150  to the air blower validator  160  through contacts (not shown) thereon. The cable and contacts may be conventional components typically used in a HVAC system. In some embodiments, a wireless connection may also be employed to couple the air blower validator  160  to the controller  150 . 
     The air blower validator  160  is configured to prove the operation of the air blower  120 . In other words, the air blower validator  160  is configured to verify that the air blower  120  is moving air. The air blower validator  160  includes an air pressure detector  162  and an air collector  164 . The air pressure detector  162  is configured to indicate if the air blower  120  is operating properly based on air pressure (static, velocity or total air pressure which is velocity pressure+static pressure) associated with the air blower  120 . The air pressure detector  162  includes a first pressure port configured to receive air from inside the air blower housing  122 . In one embodiment, the air pressure detector  162  is a pressure switch and includes a second pressure port that receives air external from the air blower housing  122 . In such an embodiment, the air pressure detector  162  compares the pressures associated with the air received from the two different locations and operates a switch based thereon. In another embodiment, the air pressure detector  162  may be a pressure transducer that converts the total pressure of the air received from the air blower housing  122  into an electrical signal. The electrical signal may then be delivered to the controller  150  to verify operation of the air blower  120 . The pressure switch and the pressure transducer may be conventional devices. The air pressure detector  162  is connected to the air blower housing  122  and coupled to the pressure tap  166  of the air collector  164 . The pressure tap  166  is coupled to the first pressure port and is positioned for the suspended opening to face the air flow direction of the air blower  120 . 
     The air collector  164  is configured to extend into the air blower housing  122  and deliver air thereof to the first pressure port. The air collector  164  includes a pressure tap  166  configured to suspend in the air blower housing with an opening that faces air flow generated by the air blower. The pressure tap  166  may be an angled device as illustrated having an opening that faces the air flow generated by the air blower. The pressure tap  166 , therefore, includes an end coupled to a pressure port of the air pressure detector and an uncoupled end that is suspended in the air blower housing  122  and faces the air flow direction during normal operation. As illustrated in  FIG. 1B , an air collector may include a supply conduit that couples a pressure tap to the supply port of an air pressure detector. 
       FIG. 1B  illustrates a diagram of an embodiment of an air blower validator  170  constructed according to the principles of the present disclosure. The air blower validator  170  is connected to an air blower housing  180 . The air blower validator  170  includes an air pressure detector  172  and an air collector  174 . The air pressure detector  172  may be an air pressure switch or an air pressure transducer as described above with respect to the air pressure detector  162  of  FIG. 1A . Coupled to a pressure port of the air pressure detector  172  is the air collector  174 . The air collector  174  includes a supply conduit  176  and a pressure tap  178 . The pressure tap  178  is directly coupled to the air blower housing  180  and positioned to capture air pressure therein. The pressure tap  178  may be mounted directly to an opening of the air blower housing  180 . The pressure tap  178 , therefore, may be used to obtain static pressure from inside the air blower housing  180 . In one embodiment, the pressure tap  178  may extend perpendicularly or at least substantially perpendicularly into the air blower housing  180  with respect thereto and be used to obtain total pressure from within the air blower housing  180 . In one embodiment, the pressure tap  178  may extend between about 0.5 inches to about 0.75 inches into the air blower housing. 
     The pressure tap  178  may include a portion that is external to the air blower housing  180  and a portion that extends into the air blower housing  180 . As illustrated, the supply conduit  176  may be external to the air blower housing  180 . The length of the supply conduit  176  may vary allowing the air pressure detector  172  to be mounted in different locations. In some embodiments, the supply conduit  176  may be rubber tubing that is typically used to provide air from different locations to pressure sensors in HVAC systems. 
     In some embodiments, such as illustrated in  FIG. 2 , an air collector may include a pressure tap having a first end configured to couple to a first pressure port of an air blower detector and a second end that is uncoupled and configured to extend into the air blower housing  122  to capture the air. The second end may include an opening that is positioned to face an air flow direction generated by the air blower during normal operation. 
       FIG. 2  illustrates a diagram of an embodiment of an air blower validator  200  constructed according to the principles of the disclosure. The air blower validator  200  includes an air pressure detector  210  and an air collector  220 . The air pressure detector  210  includes a first pressure port  212 , a second pressure port  214  (represented by embodiments  214   a  and  214   b ), electrical contact(s)  216  and a base  218  that is used to mount the air pressure detector  210  to, for example, part of an air blower. Screws, such as sheet metal screws, or other mechanical fasteners may be used to couple the air pressure detector  210  to part of an HVAC system such as the air blower housing. Alternatively, an adhesive or another means for coupling may be used to connect the air pressure detector  210 . 
     The first pressure port  212  extends from the air pressure detector  210  wherein the second pressure port  214   a  is recessed. Alternatively, the second pressure port may also extend from the air pressure detector  210  as represented by  214   b.  The air collector  220  includes a pressure tap  225  that is sized to fit over the extended first pressure port  212  and may be coupled to the first pressure port  212  via friction. In other embodiments, the pressure tap  225  may be coupled to the pressure port  212  via another means, such as an adhesive. 
     The pressure tap  225  may be constructed from rubber tubing that is typically used to provide air from different locations to pressure sensors in HVAC systems. In other embodiments, the pressure tap  225  may be constructed of another material, such as, plastic. One skilled in the art will understand that the pressure tap  225  may be constructed of various materials that allow the pressure tap  225  to be suspended in an air blower housing with an uncoupled end. 
     As illustrated, the pressure tap  225  has an angled-opening that is positioned to face the air flow generated by an air blower. The angled-opening is shaped to capture the total pressure in an air blower housing wherein the total pressure equals the static pressure and the velocity pressure. In one embodiment as illustrated, the angle of the angled-opening may be about 30 to 60 degrees with respect to longest side of the pressure tap  225 . 
     The air collector  220  may also be coupled between the second pressure port  214   b  and an opening of the air blower housing  218 . The air collector  220  may be coupled to a nipple  219  of the air blower housing  218 . Through this embodiment, the air blower validator  200  can obtain the velocity pressure via the difference of static pressure and total pressure provided to second pressure port  214   b  and first pressure port  212 , respectively. 
       FIG. 3  illustrates a flow diagram of an embodiment of a method of manufacturing an HVAC system carried out according to the principles of the disclosure. The HVAC system may be a commercial system that includes, for example, a rooftop unit. Alternatively, the HVAC system may be a residential system. Some of the steps of the method  300  may occur during manufacturing of the HVAC system. Additionally, some of the steps of the method  300  may occur during installation of the HVAC system. The method  300  begins in a step  305 . 
     In a step  310 , a pressure tap of an air collector is positioned at a location of a housing of an air blower of the HVAC system to capture air pressure in the air blower housing. The pressure tap may be used to collect total pressure or static pressure from inside the air blower housing. The air collector is part of an air blower validator that also includes an air pressure detector. In one embodiment, the air pressure detector may be, for example, a pressure switch. In another embodiment, the air pressure detector may be a pressure transducer. The location is determined to capture the maximum or at least substantially the maximum velocity pressure from the air blower. In one embodiment, the location may be within 180 to 230 degrees from the cut-off section of the air blower. 
     In a step  320 , the pressure tap is connected to a pressure port of the air pressure detector. In one embodiment, the pressure tap may be connected via a supply conduit. In another embodiment, the pressure tap may be coupled directly to the pressure port. In one embodiment, an air collector including the pressure tap may be formed as an extension of the pressure port during manufacturing of the air pressure detector. In another embodiment, the air collector may be coupled to the pressure port after manufacturing of the air pressure detector. The air pressure detector may include multiple pressure ports and more than one of the pressure ports may be coupled to the air collector to receive air from inside the air blower housing. 
     At least a portion of the pressure tap is inserted inside the air blower housing in a step  330 . A portion of the pressure tap may be inserted through an opening that was pre-cut before installation. In some embodiments, the opening may be cut during installation. A portion of the pressure tap may be inserted about 0.5 inches to about 0.75 inches into the air blower housing. The portion of the pressure tap inserted into the air blower housing suspends from the air blower housing and remains uncoupled. 
     In a step  340 , the portion of the pressure tap inserted in the air blower housing is positioned to face an air flow direction generated by the air blower. The inserted portion of the pressure tap may have an angled-opening that is positioned to face the air flow. In some embodiments, the pressure tap itself may be angled with an opening that can be positioned to face the air flow direction. For example, the pressure tap may be angled at or about 90 degrees wherein a first end is connected to the pressure port and a second end is positioned to face the air flow direction and capture air. The pressure tap is positioned to capture both velocity pressure and static pressure for the air collector. 
     The air pressure detector is then connected to the HVAC system in a step  350 . In one embodiment, the air pressure detector is connected to the air blower housing. The air pressure detector may be connected via a mechanical connection such as by using screws. The method  300  then ends in a step  360 . 
     Those skilled in the art to which this application relates will appreciate that other and further additions, deletions, substitutions and modifications may be made to the described embodiments.