US3790075A - Thermostat assembly - Google Patents

Thermostat assembly Download PDF

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Publication number
US3790075A
US3790075A US00270914A US3790075DA US3790075A US 3790075 A US3790075 A US 3790075A US 00270914 A US00270914 A US 00270914A US 3790075D A US3790075D A US 3790075DA US 3790075 A US3790075 A US 3790075A
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United States
Prior art keywords
area
calibration member
air
control rod
terminal
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00270914A
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English (en)
Inventor
E Rifkin
R Dreibelbis
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Carrier Corp
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Carrier Corp
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Publication date
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Publication of US3790075A publication Critical patent/US3790075A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F24F11/74—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity
    • F24F11/76—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity by means responsive to temperature, e.g. bimetal springs

Definitions

  • the adjustable support includes a calibration member formed of athermoplastic material.
  • the calibration member journals a control rod.
  • the position of the control rod is selectively varied to regulate the operation of the terminal to obtain a desired temperature in the area.
  • a resilient spring member cooperates with the calibration member so the member is maintained in intimate contact with the control rod, thereby preventing the rod from self rotating.
  • FIG.4 FIG.5
  • This invention relates to ceiling air terminals of the type employed in air conditioning systems, and more particularly to an improved thermostat assembly employed in combination with the ceiling air terminals for obtaining desired temperature conditions in an area being served by such terminal. Still more particularly,
  • this invention relates to an improved control rod assembly for use in air conditioning systems controls.
  • thermoplastics such as acetals
  • metals instead of metals
  • Thermoplastics have been found to be particularly suitable for many applications formerly requiring metals such as zinc, brass, and aluminum.
  • thermoplastics used throughout industry, the acetal plastics have proven to be particularly effective in applications formerly utilizing metals.
  • acetal thermoplastics commonly in use. One is a homopolymer essentially formed of a straight formal dehyde chain.
  • the other acetal thermoplastic is a copolymer, essentially formed of a trioxane chain, sold and manufactured by the Celanese Corporation under the trademark Celcon.”
  • thermostats have been used quite extensively in the manufacture of thermostats of the type disclosed in US. Pat. No. 3,595,475, issued July 27, 1971, Daniel H. Morton, inventor.
  • the thermostat disclosed in the aforecited patent has proven to be highly satisfactory when employed to regulate the operation of ceiling air conditioning terminals of the type utilizing a portion of the conditioned air supplied thereto as a control medium, to avoid the necessity of a separate control system.
  • thermostats are designed to provide extremely accurate performance within a relatively narrow operating range. However, the thermostats are often exposed to temperature conditions which greatly exceed their designed operating range.
  • thermoplastic parts also have a tendency to cold flow as a function of time.
  • the calibration member journals a control rod, which the occupant of the area being served by the air terminal may selectively adjust so a desired temperature condition is obtained in the area.
  • the calibration member is designed to provide a force to counteract any forces tending to cause the control rod to self rotate.
  • the calibration member may no longer provide the requisite counteracting force to prevent the rod from self rotating.
  • the occupant of the area establishes a desired setpoint by moving the control rod to a position corresponding to a desired temperature which he wishes in the area. Due to insufficient frictional engagement between the rod and the calibration member, caused by the members permanent deformation, the control rod may move from its desired location without the occupant being aware of such movement. Thus, after a period of time, when the temperature of the area being served by the terminal has not achieved the desired level, the occupant may not be aware of the actual reason. therefore. The occupant may think a severe malfunction exists, resulting in the occupant calling for service from a qualified Serviceman. The occupant may thence incur a relatively expensive service charge when, in effect, no service call is required.
  • a still further object of this invention is to improve the strength of thermoplastic members so regardless of their becoming deformed, they will still perform their intended function.
  • thermoplastic parts that is extremely accurate in its designed operating range, and will maintain its performance capability when exposed to extreme conditions.
  • a thermostat including a bimetallic element movable in response to ambient temperature.
  • the bimetallic element is mounted on an adjustable support member disposed in the housing of the thermostat.
  • the adjustable support member includes a calibration member adjustably secured to the housing for movement relative thereto.
  • the calibration member is formed of a thermoplastic material.
  • the calibration member journals a control rod, which may be selectively positioned by the occupant of the area, to obtain a desired temperaturecondition in the area.
  • a resilient spring member is connected to the calibration member so the portion thereof journaling the control rod is maintained in intimate contact therewith so the control rod is prevented from-self rotating.
  • FIG. 1 is a schematic'illustration of a portion of an air conditioning system illustrating an air terminal employ-
  • FIG. 4 is a perspective .view of a detailof the thermostat;
  • FIG. 5 is a sectional view taken along the lines 5-5 of FIG. 4;
  • FIG. 6 is a somewhat schematic sectional representation of the prior art.
  • a central air conditioning apparatus of the type employed in large multistory buildings including a system of duct work, a filter 5, a cooling coil 7, spray means 9, a cooling coil 11, a heating coil 13, and a fan for heating, cooling, humidifying and filtering the air as desired to provide conditioned air for passage to the areas for use in the building equipped with an air conditioning system incorporating the apparatus.
  • a supply air duct 17 is illustrative of the plurality of ducts provided to supply conditioned air to ceiling air terminals disposed in areas throughout the building.
  • the ceiling terminal includes a primary chamber 19 lined with a sound absorbing material 21 such as a glass-fiber blanket.
  • the primary chamber is ordinarily open at both ends for connecting a series of terminals end to end to provide a complete air discharge system. Suitable end pieces, not shown, are utilized to cap the end terminals in the series.
  • An air supply distribution plate 23 having a plurality of collared openings 25 therein is provided to evenly distribute the supply of air from primary chamber 19 into a distribution chamber 27 which is defined by the top and side walls of distribution plate 23.
  • the bottom of distribution chamber 27 includes aligned cut-off plates 29 which are provided with a curved surface 30 for engagement by bladders 31 and 33 of an air flow control unit to form a damper.
  • the curved surfaces smooth the flow of air through the damper to minimize the pressure drop therethrough and to minimize noise generation within the terminal.
  • the surface 30 is covered with felt 32 to further minimize noise.
  • Bladders 31 and 33 are adhesively mounted on a central partition comprised of opposed, generally convex plates 35.
  • the plates have a V-shaped recess therein so the bladders arecompletely recessed within the plates when deflated. This provides 'a large area between active walls 34 of the bladders and the cut-off plates for maximum air flow therebetween. Further, the recessed bladder provides a smooth surface along plate 35 to minimize air turbulence.
  • the damper mechanism is disposed a substantial distance upstream from the discharge openings. in the terminal to provide sufficient space therebetween to absorb any noise generated by the damper mechanism.
  • downwardly extending walls 41 which form narrow, vertical air discharge passages in conjunction with plates 35 are lined with a sound absorbing material such as glass-fiber blankets 43.
  • Outlet members 45 having outwardly flared lower portions 47 thereon are affixed by welding to walls 41.
  • the ceiling terminal disclosed hereinabove may be utilized to provide a variety of modes of terminal operation. If it is desired to maintain a constant discharge of air from the terminal,.a pressure responsive control may be employed to inflate the bladders in response to supply air pressure to reduce the area between the bladders and cut-off plates as duct pressure increases and to increase the area therebetween as duct pressure decreases.
  • the bladder inflation may be controlled by a thermostat responsive to room temperature to provide an increased quantity of air flow from the terminal as the cooling load increases and a decreased quantity of air flow from the terminal as the cooling load decreases.
  • FIG. 2 A cross-sectional view of a thermostat which has proven to be highly satisfactory in regulating the operation of the ceiling air terminal disclosed hereinabove is shown in FIG. 2.
  • Thermostat 50 includes a housing 57 having an opening formed in the lower portion thereof for passage of room air therethrough into the interior of the housing.
  • a U-shaped bimetallic element 59 is mounted within housing 57 on an adjustment block 61.
  • bimetallic element 59 is preferably provided with a plurality of perforations 62 extending throughout its axial length in both legs 60 thereof.
  • an element having a width slightly less than the interior of housing 57 may be employed.
  • the perforations in element 59 allow maximum contact between room air and element 59 for rapid and accurate response of the thermostat to variations in room temperature.
  • the adjustment block which mounts bimetallic element 59 is slidably mounted within housing 57 for vertical movement relative thereto.
  • Springs 69 are provided to bias block 61 against temperature adjustment cams 71 formed on adjustment shaft or rod 75.
  • Shaft or rod 75 is journaled in a calibration member or block 77 (See FIGS. 3 and 4) which is secured to housing 57 by calibration screw 79. The position of the calibration block may be adjusted relative to the housing by the calibration screw.
  • Resilient spring means 81 is suitably joined to calibration block 77 for reasons. to be more fully explained hereinafter.
  • a rotational force may be applied manually or otherwise to shaft 75 via adjustment lever' 85 which is affixed to the end thereof.
  • a lever 87 pivotable about a shaft 89, journaled within the side walls of housing 57, is provided to convert the vertical movement of the bimetallic element caused by temperature variations into horizontal movement.
  • a bleed plate 91 having an opening 93 therein is provided to override bleed port 95 formed within housing 57.
  • Lever 87 is therefore provided with arms 86 and 88 of unequal lengths measured from pivot 89. The short arm contacts bimetallic element 59 while the long arm contacts bleed plate 91. This provides a relatively large horizontal movement of the bleed plate to compensate for the relatively small vertical movement resulting from the use of a short bimetallic element.
  • bimetallic element 59 has a greater thickness than bimetallic elements normally employed in a thermostat of this type.
  • An adjustment screw 99 in housing 57 is provided to adjust the biasing force exerted by spring 97 against plate 91.
  • Bleed port 95 communicates with an air passage 101 within housing 57.
  • An opening 103 within housing 57, communicating with passage 101, is provided for receiving a suitable pressure regulator to provide regulated control pressure to thermostat bleed port 95.
  • a suitable pressure regulator for a description of a suitable pressure regulator, reference may be had to US. Pat. No. 3,434,409, granted Mar. 25, 1969 in the name of Daniel A. Fragnito Air is bled from the regulator through bleed port 95 to provide variable air pressureat bladders 31 in response to temperature variations in the area being treated.
  • the thermostat is preferably factory calibrated in the manner disclosed in the heretofore cited US. Pat. No. 3,595,475.
  • thermoplastic material such as an acetal plastic of the type heretofore mentioned.
  • calibration block 77 is preferably formed from such a thermoplastic material.
  • Thermoplastic parts have proven highly satisfactory in maintaining their design integrity when subjected to a relatively narrow range of operating conditions. However, the parts have not always maintained their integrity when subjected to conditions substantially in excess of their designed operating range.
  • spring member 81' includes preformed side arms 83 and 83', an upstanding wall portion 84 having the preformed side arms integrally connected thereto, and a horizontally planar portion 82, formed integrally with wall portion 84 and having an upstanding portion 82' extending therefrom.
  • the preformed side arm portions 83 and 83 are adapted to cooperate with wedge-shaped portions 76 and 76' of calibration block 77. As is illustrated in FIG. 5, the side arm portions are sprung outwardly by movement over the wedge-shaped portions. The ends of side arm members 83 and 83 are adapted to abut flange portion 78 of the calibration block to thereby maintain the top portion of the spring and the calibration block in intimate contact.
  • upstanding wall portion 82 of the resilient spring member 81 is adapted to abut a portion of the face of the calibration block, which has a slot preformed therein to provide suitable interference between the wall 82' and the front face of the calibration block.
  • the spring clamp is brought into engagement with the block.
  • Upstanding wall portion 82' of spring 81 is placed in contact'with the front face of block 77 by being aligned with the slot provided therefore.
  • Preformed side arm members 83 and 83' are placed in engaging relationship with wedge-shaped portions 76 and. 76' of block 77 so the ends of the preformed wall portions abut flange 78.
  • the control rod is then inserted in the opening in the block 77 provided therefore.
  • the surfaces of the block defining the opening yield a sufficient amount so the shaft may be readily inserted therein.
  • the material forming spring 81 is sufficiently yieldable so as to accommodate the insertion of shaft 75 into the opening.
  • Side-arm members 83 and 83' are provided to maintain the spring clamp 81 in place relative to block 77, yet permit the assembly of the clamp about the block without stressing the spring member beyond its yieldpoint.
  • Spring member 81 cooperates .with block 77 to maintain intimate contact between rod 75 and block 77.
  • Spring member 81 provides a squeezing force to maintain the desired frictional contact be tween the foregoing members of the control rod assembly.
  • the calibration block may become permanently deformed as a result of cold flowing.
  • resilient spring 81 maintains control rod 75 and calibration block 77 in intimate contact regardless of the magnitude of the deformation.
  • the squeezeforce provided by spring clamp 81 is of a sufficient magnitude to prevent any self rotation from occurring.
  • thermostat for regulating the operation of a terminal supplying conditioned air into an area so a desired temperature level can be obtained, said thermostat including a bimetallic element for sensing the temperature of the air in the area and being movable in response thereto, the improvement which comprises:'
  • A. adjustable support means including a calibration member formed of thermoplastic material, for supporting at least a portion of said bimetallic'element;
  • control means journaled by said calibration member and being selectively adjustable to position said bimetallic element so a desired temperature condition is obtained in said area;
  • said spring means includes an upstanding wall portion having side-arm portions extending integrally therefrom.
  • a control assembly for use in air conditioning system components wherein said components regulate the operation of terminal units employed in said system to discharge conditioned air into an area comprising:
  • said calibration member includes a portion having opposed wedge-shaped surfaces, and a flange normal to said wedge-shaped surfaces, said side arm portions of said spring means moving radially outward as a result of contacting said wedge-shaped surfaces the outer ends of each of said side arm portions being in intimate contact with said flange.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
  • Air-Flow Control Members (AREA)
US00270914A 1972-07-12 1972-07-12 Thermostat assembly Expired - Lifetime US3790075A (en)

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Application Number Priority Date Filing Date Title
US27091472A 1972-07-12 1972-07-12

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US3790075A true US3790075A (en) 1974-02-05

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US00270914A Expired - Lifetime US3790075A (en) 1972-07-12 1972-07-12 Thermostat assembly

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JP (1) JPS5414426B2 (enrdf_load_html_response)
GB (1) GB1439200A (enrdf_load_html_response)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3913832A (en) * 1973-01-26 1975-10-21 Tempmaster Corp Aspirating thermostat
US4047662A (en) * 1974-12-11 1977-09-13 Angelo Serratto Terminal unit for the outlet of conditioned air in a centralized conditioning system
EP0042998A3 (en) * 1980-07-02 1982-03-10 Carrier Corporation Positive shutoff for individual units of a central air conditioning system
US4416417A (en) * 1980-07-25 1983-11-22 Roger S. Sanderson Sterilized storage container
US4694988A (en) * 1986-03-10 1987-09-22 Tempmaster Corporation Control installation for variable volume air diffusers

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3913832A (en) * 1973-01-26 1975-10-21 Tempmaster Corp Aspirating thermostat
US4047662A (en) * 1974-12-11 1977-09-13 Angelo Serratto Terminal unit for the outlet of conditioned air in a centralized conditioning system
EP0042998A3 (en) * 1980-07-02 1982-03-10 Carrier Corporation Positive shutoff for individual units of a central air conditioning system
US4416417A (en) * 1980-07-25 1983-11-22 Roger S. Sanderson Sterilized storage container
US4694988A (en) * 1986-03-10 1987-09-22 Tempmaster Corporation Control installation for variable volume air diffusers

Also Published As

Publication number Publication date
GB1439200A (en) 1976-06-09
JPS5414426B2 (enrdf_load_html_response) 1979-06-07
JPS4944270A (enrdf_load_html_response) 1974-04-25

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