US3738572A

US3738572A - Air flow control system

Info

Publication number: US3738572A
Application number: US00214350A
Authority: US
Inventors: W Hall
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-08
Filing date: 1971-12-30
Publication date: 1973-06-12
Anticipated expiration: 1990-06-12

Abstract

Environmental temperatures are controlled by selectively proportioning air flow from a pair of air flow paths by generation of a force proportional to temperature and dependent solely upon temperature for oppositely and proportionally changing registration of small openings in pairs of perforated plates laterally disposed in the air flow paths. A direct-acting, expandible-material, temperature-sensitive device is located adjacent those perforated plates and is used to generate that force; and a remote-control system permits the set point of that temperature-sensitive device to be adjusted.

Description

O United States Patent 1 [111- 3,738,572 Hall, Jr. June 12, 1973 [54] AIR FLOW CONTROL SYSTEM 2,259,061 10/1941 Caffier 73/3628 Inventor: William K Hall J 4539 Bobbitt 3,235,178 2/1966 Mlles et a1. 236/13 Dallas 75229 Primary Examiner-William E. Wayner [22] Filed: Dec. 30, 1971 Attorney--Rey Eilers [21] Appl. No.: 214,350

7 B A Related US. Application Data [5 A STR CT [63] Continuatiomim an of Ser No 636 748 Ma 8 Envlronmental temperatures are controlled by selec- 1967 Pat 3 tively proportioning air flow from a pair of air flow continuation-in-part of Ser. No. 577,298, Sept. 6, Paths y generation ofa force Proportional to p 1966, abandone ture and dependent solely upon temperature for oppositely and proportionally changing registration of small [52] US. Cl. 236/49, 236/51 p g in pairs of p o ated plates laterally disposed 51 Int. Cl F24f 11/00 in the air flow p A direct-acting. xpan i le- 58 Field of Search 236/49, 13, 51; material, temperature-Sensitive device is located i 1 5 1 cent those perforated plates and is used to generate that force; and a remote-control system permits the set [56] Referen es Cit d point of that temperature-sensitive device to be ad- UNITED STATES PATENTS Justed- 922,783 5/1909 Korting 237/6 8 Claims, 25 Drawing Figures Patented June 12, 1973 3,738,572

8 Sheets-Sheet l FIG. I

Ill

FIG.2

Patented June 12, 1973 8 Sheets-Sheet 2 FIG. 3 Q

FIG. 4

Patented June 12, 1973 8 Sheets-Sheet 4 Hill [ll/l FIG. I!

Patented June 12, 1973 3,738,572

8 Sheets-Sheet 5 Patented June 12, 1973 3,738,572

8 Sheets-Sheet I;

Patented June 12, 1973 B Sheets-Sheet '7 02 fl 3 Z "7 WW 0 mm Z 6 W n u 6 a, w W, 0/

I'I'I'I.

FIG. /8.

a/ Fw w FIG. 20.

c'"""1*.'zms

AIR FLOW CONTROL SYSTEM Related Applications: This application is a continuation-in-part of application Ser. No. 636,748, filed May 8, 1967, now U.S. Pat. No. 3,669,349 issued June 13, I972 which is a continuation-in-part of application Ser. No. 577,298, filed Sept. 6, 1966, now abandoned.

This invention relates to environmental control systems and more particularly to the control of air flow from warm and cool sources. In a more specific aspect, the invention relates to a flow control system which includes pairs of relatively slidable perforated plates positioned transversely of the flow paths leading from the sources. In a still further aspect, the invention relates to the development and direct use of forces produced solely in response to change in temperature for varying relative positions of such perforated plates.

Prior Art: A wide variety of systems has been heretofore employed in the delivery of air to one or more zones where individual control of the temperature for each zone is desired. In the past, heat exchange units have been supplied for each zone with temperature sensing means for controlling the heat supplied to, or extracted from, air flowing to such zone. In air flow systems, mtor-driven mechanically-actuated dampers have been widely employed. Further, in high pressure systems, the flow of super-cooled air under high pressure to a particular area has been employed for inducing circulation.

The practical utilization of many of these previously developed temperature control systems has been limited by several factors. Many of the prior systems have not only required complex and expensive control and actuation devices for each temperature control unit, but have often required a separate control unit for each zone for which temperature control is desired. In addi- 'tion to the economic limitations thus imposed upon many previously developed systems, the complex motor-operated construction of some systems has often not been entirely satisfactory with respect to maintenance requirements or operating efficiency. Further, many of the systems previously employed for zone temperature control have not been responsive to the temperature of air in the desired zone.

Summary: In accordance with the present invention, conduit means is mounted adjacent to a supply opening leading to a zone to be temperature controlled. Structure is provided which forms a pair of air supply paths which lead to the conduit means. A pair of perforated plates are transversely disposed in each air supply path and means is provided for moving one plate of one plate pair relative to the other plate in a first sense while moving one plate of the other plate pair relative to the other plate in a second sense to increase the proportion of air supplied through one path while concur.- rently decreasing the proportion of air supplied through the second path.

The drawings: Other objects and intended advantages of this invention will be more readily appreciated as they become better understood by reference to the following detailed description in connection with the accompanying drawings wherein:

FIG. 1 illustrates a system accordingto the present invention for individually controlling the temperature in a plurality of adjacent rooms;

FIG. 2 illustrates a system for conditioning the temperature in a plurality of vertically disposed room zones;

FIG. 3 illustrates a system utilizing common returned air to temperature condition adjacently disposed room zones;

FIG. 4 is a perspective view, partially cut away, of one embodiment of the present invention;

FIG. 5 is a cross-sectional view of the sensing unit of the device shown in FIG. 4;

FIG. 6 is another perspective view of the device shown in FIG. 4;

FIG. 7 is a perspective sectional. view of a portion of the perforated plates shown in FIGS. 4 and 5;

FIG. 8 is a sectioned view of another embodiment of the perforated plates of the present invention;

FIG. 9 is a cross-sectional view of another embodiment of the perforated plates of the present invention;

FIG. 10 is a schematic diagram of a temperature conditioning system utilizing the present invention;

FIG. 11 is a perspective sectional view of the system embodying the device shown in FIG. 4;

FIG. 12 is a somewhat schematic view, partially in cross section, of the system shown in FIG. 11;

FIG. 13 is a cross-sectional view of another embodiment of a sensing unit of the present invention;

FIGS. 14-17 are perspective views, partially cut away, of four different temperature control systems utilizing perforated plate control according to the present invention;

FIG. 18 is a broken sectional view of a directacting,expandible-material, temperature-sensitive device and of part of a remote-control system to mechanically adjust the set point of that temperature-sensitive device;

FIG. 19 is a broken-away sectional view of another direct-acting, expandible-material, temperaturesensitive device and of part of a remote-control system to hydraulically adjust the set point of that temperature-sensitive device;

FIG. 20 is a broken sectional view of a further directacting,expandible-material,temperature-sensitive device and of part of a remote-control system to hydraulically adjust the set point of that temperature-sensitive device;

FIG. 21 is a broken sectional view of yet another direct-acting, expandible-fluid, temperature-sensitive device and of part of a remote-control system to mechanically adjust the set point of that temperature-sensitive device;

FIG. 22 is a broken sectional view of a still further direct-acting,expandible-material, temperature-sensitive device and of part of a remote-control system to electro-mechanically adjust the set point of that temperature-sensitive device;

FIG. 23 is a sectional view through the structure shown in FIG. 22, and it is taken along the plane indicated by the line 23-23 in FIG. 22;

FIG. 24 is a broken sectional view of still another direct-acting,expandible-material, temperature-sensitive device and of part of a remote-control system to electrically adjust the set point of that temperaturesensitive device; and

FIG. 25 is a broken sectional view of an additional direct-acting,expandible-material, temperaturesensitive, device and of part of a remote-control system to electrically adjust the set point of that temperaturesensitive device.

The Preferred Embodiments: FIGS. 13 illustrate air temperature control systems wherein warm air or cool air reservoirs common to a plurality of individual zones to be temperature controlled may be utilized with the application of the present invention. FIG. 1 discloses a control system wherein the temperature of air in several adjacently disposed rooms may be maintained individually in accordance with their separate requirements. A warm air reservoir or plenum 10, which may, for example, be an attic space fed by return air from rooms therebelow, is commonly disposed to each of the

rooms

12, 14, 16 and 18. Cool air is supplied from a suitable source through a duct 20 which forms a cool air supply path leading to a first control section 22 in a flow control unit 24 constructed in accordance with the present invention. Warm air is returned from the room 12 through the opening 26 to combine with the warm air in the reservoir to form a warm air supply path leading to a second control section 28 on the control unit 24. The control sections each comprise pairs of perforated plates, one slidable with respect to the other, and so actuated as to proportion the air flowing therethrough in dependence upon temperature, as will be described in greater detail. A fan is located in the control unit 24 to pull air through the

control sections

22 and 28 in such proportions as required to control the temperature of room 12. The air from the warm and the cool supply paths is mixed and then supplied to room 12 through

conduits

30 and 32 and through

supply openings

34 and 36, respectively.

Also illustrated in FIG. 1 is another embodiment of a system utilizing the present invention, wherein cool air from a duct 38 supplies a portion of air through openings 40 into'room 14, opening 42 into room 16,

and opening 44 into room 18 in such proportions as determined by the

control units

46 and 48, constructed in accordance with the present invention. Warm air is returned through opening 50 from room 14 into the reservoir 10 for mixture with the cool air supplied by the duct 38 in such proportions as is determined by the control unit 46. In a somewhat similar manner, warm air is supplied to an opening 52 from room 18 to be mixed with the cool air supplied by the duct 38 in such proportions as is determined by the control unit 48. The proportions of warm air and cool air are accurately controlled in response to sensing devices exposed to air of the temperature of the air in the individual rooms, thus allowing individual temperature control of each of the adjacently disposed rooms.

FIG. 2 illustrates the use of the present invention in a temperature control system for a plurality of vertically disposed rooms in a building. A cool air reservoir or plenum 54, common to a plurality of vertical rooms, contains cool air supplied by a blower 55 in a conventional cooling unit 56, which may utilize conventional dampers 58 to control the inflow of outside air. A warm air return plenum 60 contains warm exhaust air supplied by the rooms and from the cool air reservoir 54 through the grille 62. The plenum 60 is connected through conduit 63 and suitable dampers to the cooling unit 56.

As may be seen, a system utilizing the present invention may take any one of a variety of forms. For instance, the system for independently controlling the temperature of room 64 supplies conditioned air to the inlets 66 through conduits 67, the conditioned air being mixed by the control unit 68 from the warm air returned through the outlets 69 and the cool air supplied through the path 70. A similar system is shown for conditioning the air of room 72 wherein rigid ductwork 74 is utilized instead of flexible conduits. If desired, a plurality of control units may be utilized for conditioning a single room, as shown by the three

units

76, 78 and 80, which selectively proportion the amount of cool air from the reservoir 54 and the warm air from the attic plenum 82 mixed and provided to the room.

FIG. 3 illustrates a conditioning system for a pair of

rooms

84 and 86 which are commonly disposed to a warm air attic reservoir 88 and a cool air reservoir 90. Warm air from

rooms

84 and 86 flows to a common plenum 92 and a conduit 93 and thence into a conventional cooling system 94. A blower unit 95 supplies a continuous supply of cool air to the reservoir 90. Warm air also flows from the

rooms

84 and 86 into the attic reservoir 88 through openings and 87, respectively. A pair of air-mixing

control units

96 and 98, constructed in accordance with the present invention, are mounted between the warm air reservoir 88 and the cool air reservoir in order to selectively proportion the mixture of the two air supplies which is fed into

rooms

84 and 86, respectively.

While refrigeration units have been illustrated in conjunction with the embodiments described, it will be appreciated that, if desired, cold air could be provided from an outside environment and heating means could be provided to supply a source of warm air.

The construction of an air-mixing control unit in accordance with the present invention may be best understood by reference to FIGS. 4-6, wherein the unit 100 is enclosed by a main housing 102. Housing 102 is an elongated rectangular polyhedron conveniently formed of sheet metal. Housing 102 may have one or more removable panels 104 for repair or maintenance access. A pair of conventional

blower fan units

106 and 108 include rotatable vaned cages 109 and 1 10 driven by an electric motor 111. The operation of electric motor 111 is controlled by a suitably placed wall switch 112 connected through cable 113 which controls the application of power from a suitable source (not shown) to the motor. Rotation of the cages 109 and induces flow of supply air through a first perforated plate unit 114 and a second perforated plate unit 116.

Perforated

plate units

114 and 116, as shown in FIG. 6, are disposed relative to one another at an angle corresponding with the junction of warm and cool air supply paths. Rectangular flanges 1 17 and 1 18 may be provided about the outer openings of the plate sections in order to enable connection with air conduits. As shown in FIG. 7, plate unit 114 comprises a fixed plate 122 adjacent to a slidable plate 128.

Plates

122 and 128 have perforations therein which may be brought into registration or moved out of registration to open or close the air flow path and thus proportion the air passing through the housing 102. Plate unit 116 includes slidable plate 139 and fixed plate 134. Air flowing through the

plate units

114 and 116 is expelled by the fan units through their

respective outlets

119 and 120.

Referring again to FIG. 7, plate unit 114 comprises a first plate 122 which is fixedly connected at one edge to a bracket member 124 which is in turn connected to the main housing 102 of the unit. The other edge of the plate 122 is connected to housing 102 by means of a folded flange 125 (FIG. 4). Plate 122 includes a plurality of elongated perforations 126 defined therethrough in a predetermined alternating pattern. A second plate 128, comprising one-half of an integral plate having a central right angle bend, is slidable adjacent to the plate section 122. Plate 128 is connected to the rod 130, as by welding, for slide movement relative to plate 122.

Plate 128 includes a plurality of elongated perforations 132 disposed in the same pattern as the perforations 126 in the plate 122, so that the perforations in the adjoining plates may be selectively brought into registration or moved out of registration in order to control the flow of air therethrough. In FIG. 7, the

perforations

126 and 132 are disposed in exact registration so that the passage of air therethrough is substantially unimpeded. Upon a slight vertical movement of the rod 130, the perforations may be moved out of registration in order to accurately adjust the magnitude of the air flow therethrough.

The second plate unit 116 comprises a first plate 134 rigidly secured to the bracket member 136 and having a plurality of elongated perforations 138 disposed therethrough in a predetermined pattern. The plate 134 is offset with respect to the plate 122 so that the perforations through the two plates are not aligned. The second half of the bent plate, plate 139, has a plurality of perforations 140 and is adjacent to the plate 134. Because the perforation patterns of

plates

122 and 134 are offset, when the perforations of the plate unit 114 are exactly aligned, the perforations of the second plate unit 116 are unaligned. In such case, the flow of air through the second plate unit 116 is thus totally obstructed.

Upon movement of the rod 130, however, the

plates

128 and 139 would be moved relative to both the

plates

122 and 134, thereby decreasing the proportion of air allowed to pass through the first plate unit 114, while concurrently increasing the proportion of air allowed to pass through the second plate unit 116. It will be understood that fine control of the passage of air, and similar control of mixing of air from two different air supply paths, may be accomplished by the present device. Only a very small mechanical movement is required to change one pair of plates from open to closed. The elongated slot configuration shown in FIG. 7 has the distinct advantage of not requiring extremely accurate manufacturing dimensioning to provide substantial registration of the perforations while maintaining at a minimum the travel necessary to open and close a pair of plates.

FIG. 5 discloses means for moving rod 130 to adjust the positions of the perforated plates. A fluid filled sensor 141 is connected in fluid communication with a fluid chamber 142 by means of a line 144.,An insert 146 within the chamber 142 limits the upward movement of the end 148 of an elongated linkage 150. A housing 152 provides a fluid-tight seal about the linkage 150, and a bias spring 154 is disposed between the end 148 and the housing 152. A threaded portion 158 on the linkage 150 provides for connection to an extension 156 on the rod 130 in order to allow initial adjustment of the position of the rod 130 for proper alignment of the perforations.

A fluid conduit 160 connects the chamber 142 in fluid communication with an adjustment mechanism 162 comprising a hollow chamber 164 also filled with the fluid. A slidable piston 166 is biased against the fluid in the chamber 164 by a spring 168. A dial 170 may be manually turned to selectively increase or decrease the tension applied by the piston 166 against the fluid. The variance of pressure on the fluid acts on the end 148 to move the linkage vertically. By suitable adjustment of dial 170, therefore, the static position of the, rod 130 and the

outer plate sections

128 and 139 may be adjusted to provide either warmer or cooler air flow.

In operation of the present unit, the dial is set to the desired operating temperature. The sensor 141 senses air of the temperature of air in a room. If the temperature increases, the fluid inside the sensor 141 tends to expand, overcoming the bias pressure of the spring 154 and moving the linkage 150 downwardly. This causes the rod 130 and thus the

perforated plate sections

128 and 139 to move downwardly, thereby changing the registration of the perforations. This movement concurrently increases the amount of cool air and decreases the amount of warm air supplied to the room.

Conversely, if the temperature of the room air drops, the 'volume of the fluid inside the sensor 141 and the chamber 142 will decrease. Spring; 154 moves the

perforated sections

128 and 139 upward. The change causes the temperature of the air in the room to be raised. The novel construction of the present invention thus allows very accurate control of the air supply to a room in response to only a very slight mechanical movement. This movement is within the capabilities of the expandible-material sensing device 141.

Other configurations of perforations may be employed in the perforated plates. For example, FIG. 8 i1.- lustrates a plurality of substantially circular perforations 171 distributed in predetermined patterns through fixed

plates

172 and 173. A movable outer plate 174 is connected, as by welding, to the rod 176 for movement relative to the fixed

plates

172 and 173. The plate 174 includes a plurality of circular perforations which may be moved into registration with the openings of only one of the fixed

plates

172 or 173 at a time.

FIG. 8 illustrates a position of the plate 174 such that the perforations 175 are in registration with the perforations in plate 172. In this position, the perforations in plate 174 are out of registration with the openings of the plate 173, thereby preventing the passage of air therethrough. It will be understood that other configurations of perforations may also be employed for the plates, as, for example, square, rectangular, and the like.

The plates above described may advantageously be constructed of rigid material, preferably of stainless steel. Plate sections of other metals, such as aluminum or the like, may also be used when corrosion will not adversely affect operation.

It may be found advantageous to construct one or more of the plates from a flexible material, in the manner illustrated in FIG. 9. In this embodiment, the perforated plate 178 is constructed from stainless steel, while the perforated plate 180 is constructed from a flexible material, such as neoprene-covered canvas or the like. By placing the flexible plate upstream of the rigid plate section, the pressure of the air flow against the flexible plate will press it against the rigid plate, thereby minimizing the loss of air through the space be tween the plates. Alternatively, a felt-like material may be bonded to one side of two stainless steel plates of a pair, and between them, in order to cut down air loss and to resist corrosion.

FIG. 10 illustrates another embodiment of a sensing apparatus for use with the present control unit 181 above described for control of the temperature in room 184. A bimetallic circuit controller 185 is mounted on the wall 187 or in some other suitable place in order to sense the temperature of air in room 184. Such a bimetallic controller conventionally changes from one position to another in order to open or close an electrical contact (not shown). The controller 185 serves to energize and de-energize a servo motor 186 which is connected through a mechanical linkage 188 to the movable

perforated plate sections

182 and 183. Energization of the servo motor 186, also of a conventional construction, selectively varies the alignment of the perforations in the plate sections in order to control the content of the air being supplied to room 184.

FIGS. 11 and 12 illustrate a system utilizing the sensing device shown in FIG. 5. In this application, the control unit 190 has perforated

plate sections

191 and 192 operated in dependence upon an expandible-material sensor 193. Sensor 193 is disposed in an air conduit 194 which could be a short length of thin-wall electrical conduit. The conduit 194 is connected at one end to a wall panel box 196 having a perforated front panel 198 to allow the passage of air from a room therethrough. The wall panel box 196 can be an electrical outlet box of standard design. The other end of the air conduit 194 is connected to a junction box 200 mounted on the unit 190. Electric power from a suitable source may be provided to energize the blower fans in the unit 190 through

cables

204 and 206.

An electrical switch 208 is remotely disposed from the unit 190 and is mounted on the perforated panel 198 in order to allow remoted adjustment of the speed of the blower in unit 190. Similarly, a temperature selector mechanism 210, similar to that shown in FIG. 5, in fluid communication with the expandible liquid sensor 193, is mounted on the perforated panel 198 in order to allow remote adjustment of the temperature of the air of the room.

The wall panel box 196 ordinarily will be mounted in the space between room wall panels 212 and 214. The end of the air conduit 194 connected to the junction box 200 is disposed upstream of the blower of the unit 190 so that room air passes through the conduit 194 and flows over the sensor 193. If desired, the remote end of the conduit 194 may be disposed between the wall panels 212 and 214 in order to sample warm air from the room being returned to a warm air reservoir. Alternatively, the sensor 193 may be disposed in a region downstream from the blower fans of the unit 190 in order to sample the air flow to a given room.

FIG. 13 illustrates another embodiment of a suitable temperature sensor for mechanically moving perforated plates relative to one another. A housing 216 includes an inlet port 218 for entry of air whose temperature is to be sampled and further includes an annular ring 221 having outlet ports 220 for exhausting air.

A temperature-sensitive device 222 contains an expandible material and may be of the type presently or formerly manufactured by American-Standard Control Division, Detroit, Mich., and sold under the name Vernatherm. Alternatively, the temperature-sensitive expandible-material device manufactured by The Dole Valve Company, Morton Grove, 111. or the temperature-sensitive expandible-material device manufactured by Fulton Sylphon Division of Robertshaw,

Knoxville, Tenn. could be used as the temperaturesensitive unit 222. Unit 222 is mounted on a bracket 224. A piston 226 is movable into and out of unit 222 in response to expansion of the material therein in response to temperature changes. A pin 228 is connected to the piston 226 and includes a threaded portion 230 adapted to connect to a rod 232. Rod 232 is to be connected to the movable perforated plates above described. A sleeve 234 abuts a cup 236 which is biased by a spring 238. A base cup 240 abuts the lower end of spring 238 and has a central opening through which pin 228 passes.

The base cup 240 includes a threaded section 242 which threadedly mates with threads in the annular ring 221. Ring 221 also includes a threaded portion 244 which mates with threads in the housing 216. The threaded

portions

242 and 244 may be provided with threads of different pitch to allow for initial adjustment of the static position of the sensing device. A coarse adjustment may be made by rotation of the annular ring 221. A fine adjustment may be made by rotation of the base member 240 relative to the ring 221.

The sensor illustrated in FIG. 13 preferably is mounted on or near a control unit and is mechanically linked to movable perforated plates through the rod 232. The unit of FIG. 13 may be mounted in the conduit opening into a room in order to sense the temperature of the air being supplied to the room. Alternatively, it may be mounted in or near the return paths from a room. In each of these embodiments, a mechanical linkage may connect the cup 240 to a readilyaccessible manually operable wall-mounted actuator or control knob to allow adjustment of the set point.

Other applications of the present invention will be apparent upon consideration of FIGS. 14-17, wherein perforated plate control according to the present invention is utilized in four different types of temperature control systems. FIG. 14 illustrates a supply grille or conduit 246 which has a rectangular frame 248 adapted to be releasably mounted in a supply opening leading to a room. A warm air supply path 250 is partially defined by a duct collar 252 having insulation 254 installed therein. A cool air supply path 256 is located beneath the warm air supply path 250 and is defined by the collar 252 and an insulated divider partition 258.

The two

air supply paths

250 and 256 are fed into the room from suitable sources through pairs of perforate plates constructed in accordance with the present invention. More particularly, an integral perforated plate 260 is rigidly mounted between the frame 248 and a bracket 262 connected to the duct collar 252. A pair of movable

perforated plates

264 and 266 are slidably disposed in a groove in the bracket 262 and are connected to the horizontally movable bar 268. Thus, a first pair of perforated plates comprising the upper portion of plate 260 and the movable plate 264 is transversely disposed in the warm air path 250. Similarly, a second pair of perforated plates comprising the lower portion of the fixed perforated plate 260 and the movable plate 266 is transversely disposed in the cool air supply path. The plate section pairs may thus be relatively moved, in the manner previously described, to selectively adjust the registration of the perforations in adjacent plates to control the mixture of warm and cool air which is supplied to the room.

The force for moving bar 268 is provided by the power unit 270, which may, for instance, be of the expandible fluid or material type previously described. Pressure resulting from fluid expansion in the power unit 270 acts upon the head 272 of a rod 274. A spring 276 biases the head 272 against the bottom of the lower housing 278 of the power unit. The lower end of rod 274 is connected to a threaded member 280 by adjusting nut 282 in order to allow initial adjustment of the position of the perforated plates. The threaded member 280 is connected to a projection 284 from bar 268 by a plurality of screws 286. The frame 248 and the fixed perforated plate 260 are thus made to be easily removed for maintenance purposes. More particularly, screws 286 are disposed to be easily accessible upon the removal of frame 248 and plate 260 to allow the

movable plates

264 and 266 to be removed for servicmg.

FIG. illustrates the use of perforated plates in a temperature control system wherein cool air is forced into a room through a nozzle 288 and a duct 290. Return air from a warm air plenum may be selectively mixed with the cool air by means of a venturi type action created by the flow of air through the nozzle 288. This venturi action induces flow of warm air into the duct 290 through the perforated plate pairs 292 and 294.

The perforated plate pairs include a horizontally slidable plate 296 which is transversely disposed across both of the warm return air paths and also across the cool air supply path. Plate 296 is connected to a guide bar 298 which is horizontally slidably mounted upon a frame member 300 which rigidly connects nozzle 288 to the front duct frame 301. A power unit 302 is connected to move the rod 304, which in turn moves a projecting member 306 and bar 298.

A perforated plate 308 is mounted in the duct 290 adjacent to the movable perforated plate 296. The

fixed perforated plate 308 may comprise a unitary plate having a predetermined pattern of aligned perforations at the top and the bottom portions of the plate which are disposed adjacent the

movable plates

292 and 294, and a pattern of horizontally offset perforations in the middle portion of the plate which is disposed transversely across the opening of the nozzle 288.

Alternatively, the movable plate 296 may comprise three sheets mounted adjacent to each other, with the perforations of the top and bottom plate sections being aligned and the perforations of the middle plate being horizontally offset. In either embodiment, it will now be apparent that when the movable perforated plate 296 is horizontally translated in response to changes of air temperature in the room to be conditioned, the proportion of cool air supplied through the duct 290 may be selectively modulated in one sense while the porportion of warm return air is concurrently modulated in the op- I posite sense.

FIG. 16 illustrates another type of temperature control system 310, generally known as a double duct constant volume system. Warm air under a high pressure is fed through the supply inlet 312 into the housing 314, while cool air under high pressure is supplied through the inlet 316. A partition 318 divides the air supply paths inside the front portion of the housing 314. The warm and the cool air are then mixed in the back portions of the housing 314 in proportions determined by transversely disposed

perforated plates

320 and 322. The plate 322 is rigidly connected to the housing 314. Plate 320 is movable in response to movements of the temperature sensitive power unit 324. The power unit 324 moves the movable plate 320 by means of a projection 326 mounted on a transversely disposed bar 328 rigidly connectedto plate 320. The bar 328 is slidable through a slot 330in the partition 318.

The perforated plates are supported by a spacer member 332 which has provisions to allow a sliding movement of the plate 320. The perforations in the movable plate disposed in the warm air supply path are horizontally offset with respect to the perforations in the movable plate disposed inthe cool air supply path. This allows the proportion of air supplied to the room by the warm air supply path to be selectively increased while concurrently the proportion of air supplied to the room by the cool air supply path is decreased, or vice versa.

FIG. 17 illustrates the use of the present invention in a temperature control system commonly termed a high velocity induction unit. In this system, a bypass control simultaneously modulates the amount of return room air which passes over heating or cooling coils and the amount of return room air bypassed around the coils. For example, in the illustrated system of FIG. 17, return room air is induced to flow through a grille 333 and then through

perforated plate units

334 and 336. Air flow through plates 334 bypasses the heating or cooling coils in zone 337.

A baffle 338 separates the two flows of air. Air passing through plates 336 contacts the heat exchange elements in zone 337. The perforated plate pairs are constructed in a manner similar to the units previously described, with a slidable plate 340 being connected to a bracket 342 which is horizontally moved by a power unit 343. The bracket 342 slides along an edge portion of the baffle338. A fixed plate 344 is connected to the frame 346.

It will be understood from the embodiments previously described that the perforations of one perforated plate section in each of the perforated plate pairs 334 and 336 are horizontally offset with respect to one another so that the proportion of room air return supplied through one path may be concurrently increased while the proportion of room air return supplied through the second path is concurrently decreased.

Referring particularly to FIG. 18, the numeral 400 denotes one wall of an air-mixing control unit such as the air-mixing control unit of FIGS. 11 and 12. A generally-cylindrical housing 402 is suitably secured to the wall 400, adjacent an opening in that wall, by selftapping metal screws; and an air conduit 404 such as the air conduit 194 in FIGS. 11 and 12 is secured to the end wall of the housing 402. A strut 406 extends transversely of the housing 402; but that strut does not prevent the flow of air through that housing, because the width of that strut is only about one-third the inner diameter of that housing.

The numeral 408 denotes an externally-threaded sleeve which is mounted within an opening in the strut 406; and a cup-like bracket 410 has an internal thread at the right-hand end thereof which mates with the external thread on the sleeve 408. That cup-like bracket has a thread 412 at the left-hand end thereof which mates with an external thread 416 of a directacting,expandible-material, temperature-sensitive device 414 which can be a Vernatherm unit. The numeral 417 denotes the actuator of that temperature-sensitive device; and the numeral 418 denotes a flexible cable which is secured to the housing of that temperature sensitive device. That cable can be of the type used in the speedometers of automotive vehicles; and it will have its left-hand end connected to a knob or dial, not shown, located in or close to the space or room which is supplied with air by the air-mixing control unit.

The numeral 420 denotes a nut which has an internal thread that mates with the external thread on the sleeve 408. A threaded bushing 422 is held by an internal thread of the nut 420; and that bushing accommodates a reciprocable rod 424. A washer 428 is mounted on the left-hand end of the rod 424; and a helical compression spring 426 has one end thereof bearing against that washer and has the other and thereof bearing against the bushing 422. The spring 426 biases the spherical surface of the head of the rod 424 into engagement with the right-hand end of the actuator 417 of the temperature-sensitive device 414. However, that spring can yield to permit movement of the rod 424 to the right in response to right-hand movement of the actuator 417.

The air conduit 404 will have the left-hand end thereof in communication with the space or room which is supplied with air by the air-mixing control unit 400, in the same manner in which the air conduit member 194 of FIGS. 11 and 12 is in communication with the room which is supplied with air by the air-mixing control unit 190. As a result, return air will be drawn through the air conduit 404 past the temperaturesensitive device 414, through the housing 402, and then through the opening in the wall 400. That air will cause the actuator 417 of that temperature sensitive device to assume a position corresponding to the temperature of that air; and the rod 424 will respond to that position to appropriately set the perforated plates or movable dampers within the air-mixing control unit. The temperature-sensitive device 414 will be essentially inaccessible from the space or room served by the airmixing control unit; but the flexible cable 418 will enable a maintenance man within that space or room to adjust the set point of the temperature-sensitive device 414. To adjust that set point, the maintenance men will actuate the knob or dial in the room to cause the cable 418 to rotate the housing of the temperature-sensitive device 414. As that housing rotates, the thread 416 thereon will coact with the thread 412 of the cup-like bracket 410 to axially displace the actuator 417, with a consequent displacement of the rod 414. The resulting adjustment of the position of the perforated plates or movable dampers will shift the proportion of warm air introduced into the space or room to the desired value. a To lower the set point of the temperature-sensitive device 414, the housing of that temperature-sensitive device will be rotated to cause that housing to shift a short distance to the right in FIG. 18. The resulting axial displacement of the actuator 417 will force the spring 426 to yield and permit a corresponding axial displacement of the rod 224. The perforated plates or movable dampers will respond to that displacement of that rod to decrease the proportion of warm air in the air which the air-mixing control unit supplies to the space or room. As a result, the temperature of the air within the space or room will decrease to a lower average value.

As the temperature of the air within that space or room decreases, the temperature of the air flowing through the air conduit 404 will decrease correspondingly. The expandible fluid within the temperaturesensitive device 414 will respond to that decrease in temperature to experience a decrease in the volume thereof; and hence the actuator 417 will shift to the left in FIG. 18. However, the shifting of that actuator to the right in response to the rotation of the housing of the temperature-sensitive device will be greater than the shifting of that actuator to the left, in response to the reduction in the temperature of the air in the air conduit 404. As a result, the set point of the temperaturesensitive device 414 will have been lowered; and hence the average value of the temperature of the air within the space or room will have been reduced.

If the average temperature within the space or room is to be increased, the maintenance man will use the knob or dial within that space or room to cause the cable 418 to rotate the housing of the temperaturesensitive device 414 in the opposite direction. The resulting shift of that housing to the left will enable the spring 426 to shift the rod 424 to the left. Thereupon the perforated plates or movable dampers within the housing of the air-mixing control unit will supply a higher percentage of warm air and hence the average temperature within the space or room will be increased.

As the temperature of the air within that space or room increases, the temperature of the air flowing through the air conduit 404 will increase correspondingly. The expandible-material within the temperaturesensitive device 414 will respond to that increase in temperature to experience an increase in the volume thereof; and hence the actuator 417 will shift to the right in FIG. 18. However, the shifting of that actuator to the left, in response to the rotation of the housing of the temperature-sensitive device 414, will be greater than the shifting of that actuator to the right, in response to the increase in the temperature of the air in the air conduit 414. As a result, the set point of the temperature-sensitive device 414 will have been increased; and hence the average value of the temperature of the air within the space or room will have been increased.

()nce the set point of the temperature-sensitive device 414 has been set, that temperature-sensitive device will automatically operate to maintain a corresponding average temperature within the space or room. If the temperature of the air within the space or room tends to fall below that average temperature, the temperature of the air flowing through the air conduit 404 will decrease; and the resulting reduction in volume of the expandible material within the temperaturesensitive device 414 will permit the actuator 417 to move to the left. The spring 426 will provide a corresponding movement of the rod 424 to the left with a consequent increase in the proportion of warm air introduced into the space or room by the air-mixing control unit. The overall result is that the temperature of the air within the space or room will move back up to the desired level, and the actuator 417 and rod 424 will return to their'set positions. Conversely, if the temperature of the air within the space or room tends to rise above the average temperature, the temperature of the air flowing through the air conduit 404 will increase; and the resulting increase in volume of the expandible material within the temperature-sensitive device 414 will cause the actuator 417 to shift to the right. The

spring 426 will yield to permit a corresponding shift of the rod 424 to the right with a consequent decrease in the proportion of warm air supplied to the space or room by the air-mixing control unit. The overall result is that the temperature of the air within the space or room will move back down to the desired level, and the actuator 417 and rod 424 will return to their set positions.

It thus should be apparent that by using the structure in FIG. 18, it is easy to adjust the set point of the temperature sensitive device 414 from a point within the space or room. This is important because that temperature-sensitive device is essentially inaccessible from that space or room being located immediately adjacent the wall 400 of the air-mixing control unit.

The left-hand end of the air conduit 404 will preferably be in direct communication with the space or room, as indicated by FIGS. 11 and 12; so air from that space or room can pass directly into that air conduit and thence directly to the temperature-sensitive device 414. To minimize costs of installation, the cable 418 will usually be located within that air conduit; and the knob or dial on that cable will usually be mounted on a perforated plate at the outer face of a wall panel box to which that air conduit is connected. However, if desired, the cable 418 could have a substantial portion of the length thereof disposed outwardly of the air conduit 418; and it could have the knob or dial therefor located in a box or panel which was located in a corridor or hall exteriorly of the space or room.

FIG. 19 shows a remote-control arrangement which is specifically different from the remote-control arrangement of FIG. 18, although some of the components thereof are identically numbered and can be identical. The numeral 432 denotes L-shaped brackets which are secured to the inner surface of the cylindrical housing 402; and those brackets fixedly support an annular plate 434 which has a concave annular recess 436 in the right-hand face thereof. A liquid-tight annulus 438 of expandible material is cemented or otherwise secured in position within the concave annular recess 436; and a concave annular recess 442 in the left-hand face of a circular plate 440 also is cemented or otherwise secured to that expandible annulus. The circular plate 440 is supported by the expandible annulus 438, but it is biased toward the annular plate 434 by spring clips 443 which are suitably secured to the inner surface of the housing 402.

The circular plate 440 has air passages 444 therethrough, and also has a central passage which accommodates an externally-threaded sleeve 446. Nuts 448 are threaded onto that sleeve in abutting engagement with the opposite faces of that circular plate to fixedly secure that sleeve to that plate. A nut 450 is threaded onto the left-hand end of the sleeve 446, and the external thread 454 of a temperature-sensitive device 452, which can be a Vernatherm unit. is held by an internal thread of that nut. The spring 426 holds the head of the rod 424 in engagement with the actuator 456 of that temperature-sensitive device. The numeral 458 denotes a hollow tube which has the right-hand end thereof connected to the expandible annulus 438, and which has the lefthand end thereof connected to a transducer 468 that responds to the rotation of a knob 470 to change the pressure on the liquid therein and thus on the liquid within the tube 458 and within the expandible annulus 438. The transducer 468 is located within a wall box 460 that is disposed between two

walls

464 and 466; and the front of that wall box is covered by a perforated plate 462 which can be identical to the plate 198 in FIGS. 11 and 12.

The perforated plate 462 will preferably be located in the space or room which is supplied with air by the air-mixing control unit of which the wall 400 is a part. That air-mixing control unit will draw some of the return air from that space or room through the perforations of that plate, through the air conduit 404, past the temperature-sensitive device 452, through the center of the annular plate 434, through the openings 444 of the circular plate 440, and then through the opening in the wall 400. That air will cause the expandible material within that temperature-sensitive device to assume a volume comparable to that temperature.

To adjust the set point of the temperature-sensitive device 452, the maintenance man will rotate the knob 470, and will thereby change the pressure on the liquid within the transducer 468, within the tube 458, and within the expandible annulus 438. If that maintenance man rotates the knob 470 in a direction which reduces the pressure within the expandible annulus 438, the spring clips 443 will reduce the thickness of that expandible annulus by shifting the circular plate 440 to the left; and thus will shift the sleeve 446, the nut 450, the temperature-sensitive device 452, the spring 426 and the rod 424 to the left. That shift will cause the perforated plates or movable dampers within the airmixing control unit to increase the proportion of warm air which that air-mixing control unit will supply to the space or room. Consequently, the average temperature of the air within that space or room will increase.

As the temperature of the air within that space or room increases, the temperature: of the air flowing through the air conduit 404 will increase correspondingly. The expandible fluid within the temperaturesensitive device 452 will respond to that increase in temperature to experience an increase in the volume thereof; and hence the actuator 456 will shift to the right in FIG. 19. However, the shifting of that actuator to the left, in response to the reduction in thickness of the expandible annulus 438, will be greater than the shifting of that actuator to the right, in response to the increase in the temperature of the air in the air conduit 404. As a result, the set point of the temperaturesensitive device 452 will have been raised; and hence the average value of the temperature of the air within the space or room will have been increased.

If the maintenance man rotates the knob 470 in a direction which increases the pressure within the expandible annulus 438, the thickness of that expandible annulus will increase with a consequent shift of circu lar plate 440, sleeve 446, nut 45 0, the temperaturesensitive device 452, spring 426 and rod 424 to the right. That shift will cause the perforated plates or movable dampers within the air-mixing control unit to decrease the proportion of warm air which that air-mixing control unit will supply to the space or room. Consequently, the average temperature of the air within that space or room will decrease.

As the temperature of the air within that space or room decreases, the temperature of the air flowing through the air conduit 404 will decrease correspondingly. The expandible material within the temperaturesensitive device 452 will respond to that decrease in temperature to experience a decrease in the volume thereof; and hence the actuator 456 will shift to the left in FIG. 19. However, the shifting of that actuator to the right, in response to the increase in thickness of the expandible annulus 438, will be greater than the shifting of that actuator to the left, in response to the decrease in the temperature of the air in the air conduit 404. As a result, the set point of the temperature-sensitive device 452 will have been lowered; and hence the average value of the temperature of the air within the space or room will have been decreased.

Once the set point of the temperature-sensitive device 452 has been set, that temperature-sensitive device will automatically operate to maintain a corresponding average temperature within the space or room in the manner described hereinbefore in connection with FIG. 18. It thus should be apparent that by using the structure in FIG. 19, it is easy to adjust the set point of the temperature-sensitive device 452 from a point within the space or room. This is important because that temperature-sensitive device is essentially inaccessible from that space or room.

FIG. shows a remote control arrangement which is specifically different from the remote-control arrangement of either of FIGS. 18 and 19, although some of the components thereof are identically numbered and can be identical. The external thread 454 of a temperature-sensitive device 452 is mounted within the internal thread 412 of a cup-like bracket 410, and that cup-shaped bracket has a slot 459 therein which accommodates the inlet fitting ofa hydraulic cylinder 472 that has a piston 474. That hydraulic cylinder is dimensioned so it can slide freely within the cup-like bracket 410; and the actuator 456 of the temperature-sensitive device 452 bears against the closed end of that hydraulic cylinder, while the piston 474 bears against the head of the rod 424. The air-mixing control unit, of which the wall 400 is a part, will draw air through the air conduit 404, past the temperature-sensitive device 452, and past the strut 406 through the opening in the wall 400. The temperature of that air will cause the expandible-material within that temperature-sensitive device to assume a volume which is comparable to that temperature.

The spring 426 urges the head of the rod 424 against the piston 474 of the hydraulic cylinder 472, and thereby urges the left-hand end of that hydraulic cylinder against the actuator 456 of the temperaturesensitive device 452. To adjust the set point of that temperature-sensitive device, the maintenance men will rotate the knob of a pressure transducer, such as the pressure transducer 468 in FIG. 19, to change the pressure on the hydraulic liquid within the hydraulic cylinder 472. If that knob is rotated to reduce the pressure on that hydraulic liquid, the spring 426 will be able to force the piston 474 further into the hydraulic cylinder 472 and will thereby be able to shift the rod 424 further to the left with a consequent increase in the set point of the temperature-sensitive device 452. On the other hand, if the knob of the pressure transducer is rotated to increase the pressure on the hydraulic fluid within the hydraulic cylinder 472, the piston 474 will force the spring 426 to yield and permit the rod 424 to shift to the right with a consequent decrease in the set point of the temperature-sensitive device 452. In this way, the set point of that temperature-sensitive device can be set at any desired level by merely rotating the knob of the transducer.

When the set point of the temperature-sensitive device 452 is being increased, the temperature of the air flowing through the air conduit 404 will increase; and that temperature-sensitive device will tend to shift the rod 424 to a position wherein the proportion of warm air will be reduced. Conversely, as that set point is being decreased, the temperature of the air flowing through the air conduit 404 will decrease; and that temperature-sensitive device will tend to permit the spring 426 to shift the rod 424 to a position wherein the proportion of warm air will be increased. However, because the movement of the piston 474 can be much greater than temperature-induced movement of the actuator 456, the change in the set point of the temperature-sensitive device 452 will be essentially controlled by the movement of that piston rather than by the temperature-induced movement of the actuator 456.

Once the set point of the temperature-sensitive device 452 in FIG. 20 has been set, that temperaturesensitive device will automatically operate to maintain a corresponding average temperature within the space or room in the manner described hereinbefore in connection with FIG. 18. It thus should be apparent that by using the structure in FIG. 20 it is easy to adjust the set point of the temperature-sensitive device 452 from a point within the space or room. This is important because that temperature-sensitive device is essentially inaccessible from that space or room.

FIG. 21 shows a remote control arrangement which is specifically different from the remote-control arrangements of FIGS. 1820, although some of the components thereof are identically numbered and can be identical. The external thread 454 of a temperaturesensitive device 452 is mounted within the internal thread 412 of a cup-like bracket 410, and that cupshaped bracket has a long slot 477 in the bottom thereof which accommodates the crank arm 482 of generally-elliptical cam 480. A bearing element 476, which is generally cylindrical in form but which has a frusto-conical right-hand end, is slidably interposed between the actuator 456 of the temperature-sensitive device 452 and the cam 480. A 'bearing element 478, which is generally cylindrical in form but which has a frusto-conical left-hand end and a reduced diameter cylindrical right-hand end, is slidably interposed between the cam 480 and the head of the rod 424. A flexible cable 484 has the right-hand end of the reciprocable center element thereof connected to the crank arm 482; and it will have the left-hand end of that center element suitably connected to a lever, knob or dial, not shown. A bracket 486 holds the sheath of that flexible cable against shifting relative to the crank arm 482.

The spring 426 will urge the head of the rod 424 against the right-hand face of the bearing element 478, will urge the left-hand face of that bearing element into engagement with the cam 480, will urge that cam into engagement with the right-hand face of the bearing element 476, and will urge the left-hand face of that bearing element into engagement with the actuator 456. Whenever the crank arm 482 is in the solid-line position of FIG. 21, the rod 424 will be in a position where only a limited proportion of warm air will be supplied to the space or room by the air-mixing control unit of which the wall 400 is a part. However, whenever that crank arm is in the dotted-line position in FIG. 21, the rod 424 will be spaced to the left of the position shown in that FIGURE, and it will permit a large proportion of warm air to be introduced into that space or room. As a result, by appropriate manipulation of the lever, knob or dial which is connected to the left-hand end of the reciprocable inner element of the cable 484, a maintenance man can set any desired set point for the temperature-sensitive device 452.

When the set point of the temperature-sensitive device 452 is being increased, the temperature of the air flowing through the air conduit 404 will increase; and that temperature sensitive device will tend to shift the rod 424 to a position wherein the proportion of warm air will be reduced. Conversely, as that set point is being decreased, the temperature of the air flowing through the air conduit 404 will decrease; and that temperature-sensitive device will tend to permit the spring 426 to shift the rod 424 to a position wherein the proportion of warm air will be increased. However, because the movement of the cam 480 can be much greater than temperature-induced movement of the actuator 456, the change in set point of the temperaturesensitive device 452 will be essentially controlled by the movement of that cam rather than by the temperature-induced movement of the actuator 456.

Once that set point has been set, that temperaturesensitive device will automatically operate to maintain.

a corresponding average temperature within the space or room. If the temperature of the air within the space or room tends to fall below that average temperature, the temperature of the air flowing through the air conduit 404 will decrease; and the resulting reduction in volume of the expandible material within the temperature-sensitive device 452 will permit the actuator 456 to move to the left. The spring 426 will then shift rod 424, bearing element 478, cam 480 and bearing element 476 to the left with a consequent increase in the proportion of warm air introduced into the space or room by the air-mixing control unit. The overall result is that the temperature of the air within the space or room will move back up to the desired level, and the actuator 456 and rod 424 will return to their set positions. Conversely, if the temperature of the air within the space or room tends to rise above the average temperature, the temperature of the air flowing through the air conduit 404 will increase; and the resulting increase in volume of the expandible material within the temperature-sensitive device 452 will cause the actuator 456 to shift to the right. The spring 426 will yield to permit a corresponding shift of bearing element 476, cam 480, bearing element 478 and rod 424 to the right with a consequent decrease in the proportion of warm air supplied to the space or room by the airmixing control unit. The overall result is that the temperature of the air within the space or room will move back down to the desired level, and the actuator 456 and rod 424 will return to their set positions.

It thus should be apparent that by using the structure in FIG. 21, it is easy to adjust the set point of the temperature-sensitive device 452 from a point within the space or room. This is important, because that temperature-sensitive device is essentially inaccessible from that space or room.

FIGS. 22 and 23 show a remote control arrangement which is specifically different from the remote-control arrangement of each of FIGS. 18-21, although some of the components thereof are identicallynumbered and can be identical. The circular plate 440 differs from the similarly-numbered plate in FIG. 19 in having inclined planes 490, rather than an expandible annulus, secured to the left-hand face thereof. Those inclined planes engage inclined planes 492 which are part of a frame that includes vertically-directed spacers 493. That frame is confined and guided on the left by the fixed annular plate 434, and it is confined and guided on the right by the inclined planes 490. Helical extension springs 496 bias that frame upwardly toward the top of the housing 402.

The numeral 498 denotes a nut which is fixedly secured to the upper surface of the housing 402; and that nut surrounds an opening in that upper surface. That nut receives the external thread on a temperaturesensitive device 500 such as a Vernatherm unit. A heating coil 502 is mounted in heat-exchanging relation with the temperature-sensitive device 500; and conductors 508 extend between that heating coil and an adjustable power source, not shown, which is mounted behind a control panel 504 and which is controlled by a knob 506. While various forms of adjustable power sources could be used to control the amount of current flowing through the heating coil 502, one of the standard light dimmers, which are mounted in electrical outlet boxes to control the lights within rooms in residences, could be used. Also, if desired, a silicon controlled rectifier and a firing circuit therefor could be used to vary the amount of power supplied to the heating coil 502.

The spring clips 443 will urge the circular plate 440 to the left in FIG. 22, and thus will cause the inclined planes-490 to apply upwardly-directed forces to the inclined planes 492. In addition, the springs 496 will apply upwardly'directed forces to the inclined planes 492. However, the actuator of the temperature sensitive device 500 overlies and bears against the up permost inclined plane 492, and thereby limits the extent to which those inclined planes can move upwardly. As the inclined planes 490 respond to the forces from the spring clips 443 to apply upwardly-directed forces to the inclined planes 492, the latter inclined planes will apply downwardly-directed forces to the inclined planes 490, and thus to the circular plate 440. The rod 424 will resist those downwardly-directed forces; but, if desired, anti-friction skids or rollers could be provided at the lower edge of the lower inclined plane 490 to keep'those inclined planes from shifting downwardly from the position shown in FIGS. 22 and 23.

To adjust the set point of the temperature-sensitive device 452 in FIGS. 22 and 23, the maintenance man will shift the knob 506 to a desired position. Specifically, to raise the set point of that temperature-sensitive device, the maintenance man will shift the knob 506 to a position wherein less current will flow through the heating coil 402. Thereupon, the volume of the expandible material within the temperature-sensitive device 500 will decrease; and the springs 496 will move the inclined planes 492 and the actuator of the latter temperature-sensitive device upwardly. The spring clips 443 then will shift the inclined planes 490 and the circular plate 440 to the left; and the resulting shift of the rod 424 to the left will increase the proportion of warm air which the air-mixing control unit, of which the wall 400 is a part, will introduce into the space or room. The consequent increase in the temperature of the air flowing into the housing 402 from the air con duit 404 will cause the expandible material within the temperature-sensitive device 452 to expand, and to act through the actuator of that temperature-sensitive device to shift the rod 424 to the right. However, the change in the temperature of the expandible material within the temperature-sensitive device 500 will be so much greater than the change in the temperature of the material within the temperature-sensitive device 452 that the new set point of the latter temperaturesensitive device will provide an increase in the proportion of warm air introduced into the space or room.

Conversely, to lower the set point of the temperature-sensitive device 452 in FIG. 22 and 23, the maintenance man will shift the knob 506 to a position wherein more current will flow through the heating coil 502. The resulting increase in volume of the expandible material within the temperature-sensitive device 500 will force the actuator of that temperature-sensitive device and the inclined planes 492 to move downwardly. The consequent shift of the inclined planes 490 to the right will cause the sleeve 446 to shift the rod 424 to the right, and thereby move the perforated plates or movable dampers of the air-mixing control unit to reduce the proportion of warm air introduced into the space or room. The resulting reduction in the temperature of the air flowing through the air conduit 404 will permit the expandible material within the temperature-sensitive device 452 to contract; and the helical compression spring 426 within the sleeve 446 will shift the rod 424 to the left. However, the change in the temperature of the expandible-material within the temperaturesensitive device 500 will be so much greater than the change in the temperature of the expandible material within the temperature-sensitive device 452 that the new set point of the temperature-sensitive device 452 will provide a decrease in the proportion of warm air introduced into the space or room.

FIG. 24 shows the temperature-sensitive device 414 of FIG. 18 equipped with a heating coil 502 rather than with the flexible cable 418. Conductors 508 extend from that heating coil to a variable-power source, not shown, such as that which is controlled by the knob 506 in FIG. 22. To adjust the set point of the temperaturesensitive device 414 in FIG. 24, the maintenance man will actuate that variable-power source to change the amount of current flowing through the heating coil 502.

If the maintenance man actuates the variable-power source to decrease the current flowing through the heating coil 502 in FIG. 24, the volume of the expandible material within the temperature-sensitive device 414 will decrease; and the spring 426 will shift the rod 424 and the actuator 417 to the left with a consequent increase in the proportion of warm air introduced into the space or room by the air-mixing control unit of which the wall 400 is a part. As a result, the set point of that temperature-sensitive device will have been raised. However, if the maintenance man actuates the variable-power source to increase the current flowing through the heating coil 502 in FIG. 24, the resulting increase in the volume of the expandible material within that temperature-sensitive device will shift the actuator 417 and the rod 424 to the right with a consequent decrease in the proportion of warm air introduced into the space or room. As a result, the set point of that temperature-sensitive device will have been lowered.

When the set point of the temperature-sensitive device 414 is being increased, the temperature of the air flowing through the air conduit 404 will increase; and that temperature-sensitive device will tend to shift the rod 424 to a position wherein the proportion of warm air will be reduced. Conversely, as that set point is being decreased, the temperature of the air flowing through the air conduit 404 will decrease, and that temperature-sensitive device will tend to permit the spring 426 to permit the spring 426 to shift the rod 424 to a position wherein the proportion increased, in the temperature of the expandible material within the temperature-sensitive device 414, due to the change in current flow through the heating coil 502, will be so much greater than the change in that expandible material due to changes in temperature of the air flowing through air conduit 404, the set point of the temperature sensitive device 414 will be essentially controlled by the heat from the heating coil 502.

Once the desired set point has been established for the temperature-sensitive device 414 in FIG. 24, that temperature sensitive device will respond to the temperature of the air flowing through the air conduit 404 to appropriately adjust the position of the rod 424. As a result, that temperature-sensitive device will be able to maintain the desired temperature level within the space or room.

FIG. 25 shows a temperature-sensitive device 510 disposed within a cup-like bracket 410 in lieu of the hydraulic cylinder 472 of FIG. 20 or of the rotatable cam 480 and the bearing

elements

476 and 478 of FIG. 21. The actuator 512 of the temperature-sensitive device 510 is aligned with, and abuts, the actuator 456 of a temperature-sensitive device 452 which has the external thread 454 thereof mounted within an internal thread at the left-hand end of that cup-shaped bracket. The helical compression spring 426 within the cupshaped bracket 410 urges the head of the rod 424 against the housing of the temperature-sensitive device 510 and thereby urges the actuator 512 of that temperature-sensitive device into abutting engagement with the actuator 456 of the temperature-sensitive device 454. A heating coil 502 is wound around the housing of the temperature sensitive device 510; and conductors 508 extend to a variable power source such as the variable-power source controlled by the knob 506 in FIG. 22.

If a maintenance man adjusts the variable powersource to decrease the current flowing through the heating coil 502 in FIG. 25, the volume of the expandible material within the temperature-sensitive device 510 will decrease; and the spring 426 will shift the rod 424 and the housing and actuator of that temperaturesensitive device and the actuator of temperaturesensitive device 452 to the left. Such a shift will increase the proportion of warm air introduced into the space or room by the air-mixing control unit of which the wall 400 is a part. As a result, the set point of the temperature-sensitive device 452 will have been raised. However, if the maintainance man actuates the variable-power source to increase the current flowing through the heating coil 502 in FIG. 25, the resulting increase in the volume of the expandible material within that temperature-sensitive device will shift the actuator 456 and the actuator and housing of that temperature-sensitive device to the right. That shift will decrease the proportion of warm air introduced into the space or room. As a result, the set point of the temperature-sensitive device 452 will have been lowered.

When the set point of the temperature-sensitive device 452 in FIG..25 is being increased, the temperature of the air flowing through the air conduit 404 will increase; and that temperature-sensitive device will tend to shift the rod 424 to a position wherein the proportion of warm air will be reduced. Conversely, as that set point is being decreased, the temperature of the air flowing through the air conduit 404 will decrease; and that temperature-sensitive device will tend to permit the spring 426 to shift the rod 424 to a position wherein the proportion of warm air will be increased. However, because the change in the temperature of the expandible material within the temperature-sensitive device 510 will be so much greater than the change in the temperature of the expandible material within the temperature-sensitive device 452, the new set point of the latter temperature-sensitive device will be essentially controlled by the adjustment of the amount of current flowing through the heating coil 502.

The embodiments of FIGS. 13 and 18-25 are particularly desirable. Those embodiments enable Vernatherm units to be used to control the settings of the perforated plates or adjustable dampers of air-mixing control units, and yet permit the set points of those Vernatherm units to be readily adjusted even though those Vernatherm units are essentially inaccessible from the spaces or rooms where the control levers, knobs, or dials are located.

Whereas the present specification has been described in considerable detail with respect to several embodiments, it is to be understood that this description is merely for the purposes of illustration and that changes or variations in the described embodiments may be made by persons skilled in the art without departing from the scope of the invention as defined in the ap pended claims.

What I claim is:

l. A system for controlling the temperature within a conditioned space which comprises an air-handling control unit that is connected to said conditioned space to supply air to said conditioned space, means within said air-handling control unit to create a pressure in said air-handling control unit which is less than the pressure within said conditioned space, an elongated sampling passage extending between and in communication with said conditioned space and said airhandling control unit so air can flow from said conditioned space through said sampling passage to said airhandling control unit, a temperature-sensitive device that has an adjustable set point, said temperaturesensitive device being located so it is not readily accessible from said conditioned space, said temperaturesensitive device being mounted adjacent the outlet end of said sampling passage so it is close to said airhandling control unit and so the air passing through said sampling passage directly engages said temperature-sensitive device, whereby said temperaturesensitive device can sense the temperature of said air which flows from said conditioned space through said sampling passage to said air-handling control unit, an adjusting means with a settable element which is settable to set said adjustable set point of said temperaturesensitive device, said adjusting means being mounted adjacent the inlet end of said sampling passage and thus being mounted so it is remote from said temperaturesensitive device, connecting means extending from said adjusting means to said temperature-sensitive device to enable the adjusting of said settableelement of said adjusting means to adjust said adjustable set point of said temperature-sensitive device, and mechanical connecting means connecting said temperature-sensitive device to said air-handling control unit to enable changes in the temperature of said air which flows from said conditioned space through said sampling passage to said air-handling control unitto enable said temperature-sensitive device to cause said air-handling control unit to adjust the temperature of the air which it supplies to said conditioned space, said temperaturesensitive device being mounted adjacent said airhandling control unit so said mechanical connecting means can be short in length and thus can have a small mass, the first said connecting means being disposed within and extending through said sampling passage, whereby said sampling passage performs the dual functions of conducting air from said conditioned space to said temperature-sensitive device and of enclosing and protecting said first said connecting means.

2. A system as claimed in claim 1 wherein said means within said, air-handling control unit is a motor-driven blower, wherein said sampling passage is connected to the suction side of said motor-driven blower, wherein said sampling passage is a small cross-section tube located within a wall of said conditioned space, and wherein said mechanical connecting means includes a push-pull linkage.

3. A system as claimed in claim 1 wherein a portion of said mechanicalconnecting means provides said adjustable set point for said temperature-sensitive device, and wherein said portion of said mechanical connecting means responds to a change in the setting of said settable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperaturesensitive device.

4. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said adjustable set point for said temperature-sensitive device,

wherein said portion of said mechanical connecting means includes a hydraulic cylinder and the piston thereof, and wherein said hydraulic cylinder and the piston thereof respond to a change in the setting of said settable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperaturesensitive device.

5. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said adjustable set point for said temperature-sensitive device,

wherein said portion of said mechanical connecting means includes a cam that is movable to vary the effective distance between said temperature-sensitive device and said air-handling control unit, wherein an actuator for said cam is movable by said settable element of said adjusting means, and wherein said cam and actuator therefor respond to a change in the setting of saidsettable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperaturesensitive device.

Claims

1. A system for controlling the temperature within a conditioned space which comprises an air-handling control unit that is connected to said conditioned space to supply air to said conditioned space, means within said air-handling control unit to create a pressure in said air-handling control unit which is less than the pressure within said conditioned space, an elongated sampling passage extending between and in communication with said conditioned space and said air-handling control unit so air can flow from said conditioned space through said sampling passage to said air-handling control unit, a temperature-sensitive device that has an adjustable set point, said temperature-sensitive device being located so it is not readily accessible from said conditioned space, said temperature-sensitive device being mounted adjacent the outlet end of said sampling passage so it is close to said air-handling control unit and so the air passing through said sampling passage directly engages said temperaturesensitive device, whereby said temperature-sensitive device can sense the temperature of said air which flows from said conditioned space through said sampling passage to said airhandling control unit, an adjusting means with a settable element which is settable to set said adjustable set point of said temperature-sensitive device, said adjusting means being mounted adjacent the inlet end of said sampling passage and thus being mounted so it is remote from said temperature-sensitive device, connecting means extending from said adjusting means to said temperature-sensitive device to enable the adjusting of said settable element of said adjusting means to adjust said adjustable set point of said temperature-sensitive device, and mechanical connecting means connecting said temperature-sensitive device to said air-handling control unit to enable changes in the temperature of said air which flows from said conditioned space through said sampling passage to said air-handling control unit to enable said temperature-sensitive device to cause said airhandling control unit to adjust the temperature of the air which it supplies to said conditioned space, said temperature-sensitive device being mounted adjacent said air-handling control unit so said mechanical connecting means can be short in length and thus can have a small mass, the first said connecting means being disposed within and extending through said sampling passage, whereby said sampling passage performs the dual functions of conducting air from said conditioned space to said temperaturesensitive device and of enclosing and protecting said first said connecting means.

2. A system as claimed in claim 1 wherein said means within said air-handling control unit is a motor-driven blower, wherein said sampling passage is connected to the suction side of said motor-driven blower, wherein said sampling passage is a small cross-section tube located within a wall of said conditioned space, and wherein said mechanical connecting means includes a push-pull linkage.

3. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said Adjustable set point for said temperature-sensitive device, and wherein said portion of said mechanical connecting means responds to a change in the setting of said settable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperature-sensitive device.

4. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said adjustable set point for said temperature-sensitive device, wherein said portion of said mechanical connecting means includes a hydraulic cylinder and the piston thereof, and wherein said hydraulic cylinder and the piston thereof respond to a change in the setting of said settable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperature-sensitive device.

5. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said adjustable set point for said temperature-sensitive device, wherein said portion of said mechanical connecting means includes a cam that is movable to vary the effective distance between said temperature-sensitive device and said air-handling control unit, wherein an actuator for said cam is movable by said settable element of said adjusting means, and wherein said cam and actuator therefor respond to a change in the setting of said settable element of said adjusting means to change the effective distance between said temperature-sensitive device and said air-handling control unit and thereby change said adjustable set point for said temperature-sensitive device.

6. A system as claimed in claim 1 wherein a portion of said mechanical connecting means provides said adjustable set point for said temperature-sensitive device, wherein said portion of said mechanical connecting means includes a second temperature-sensitive device and a heating coil in heat-transferring relation with said second temperature-sensitive device, wherein adjusting of said settable element of said adjusting means will change the value of the current flowing to said heat coil, and wherein said heat coil responds to a change in the setting of said settable element of said adjusting means to change the amount of heat supplied to said second temperature-sensitive device and thereby enable said said second temperature-sensitive device to change the effective distance between the first said temperature-sensitive device and said air-handling control unit with a consequent change in said adjustable set point for said first said temperature-sensitive device.

7. A system as claimed in claim 1 wherein an expandible element helps provide said adjustable set point for said temperature-sensitive device, wherein said expandible member is expandible to effect movement of said temperature-sensitive device in one direction relative to said air-handling control unit, wherein said expandible element is contractible to effect movement of said temperature-sensitive device in the opposite direction relative to said air-handling control unit, and wherein said expandible member responds to shifting of said settable element of said adjusting means in one direction to expand and responds to shifting of said settable element of said adjusting means in the opposite direction to contract.

8. A system as claimed in claim 1 wherein a second temperature-sensitive element and a heat coil help provide said adjustable set point for said temperature-sensitive device, wherein said heating coil is in heat-transferring relation with said second temperature-sensitive device, wherein a change in the current flowing through said heating coil will enable said second temperature-sensitive device to change the effective distance between the first said temperature-sensitive device and said air-handling control unit and thereby change said adjustAble set point for said first said temperature-sensitive device, and wherein a change in the setting of said settable element of said adjusting means will change the amount of current flowing through said heating coil.