US2117477A - Ventilating system - Google Patents

Description

M y 7, 1938. J. R. HALL VENTILATING SYSTEM Filed March 12, 1936 5 Sheets-Sheet 1 Rm Q 7! 1 fi w? 1 V Q 6m 0 g 1 Q 8w m 1 aw?" 2 ..H NQNMN & 1 k s May 17, 1938. J. R. .HALL 2,l17,477

' VENTILA'IING SYSTEM Filed March 12, 1936 3 Sheets-Sheet 2 A k May 17, 1938. J. R. HALL VENTILATING SYSTEM 3 Sheets-Sheet 3 Filed larch 12, 1956 Patented May. 17, 1938 United States Air Conditioning Corporation, Minneapolis, Minn, a corporation of Minnesota Application March 12, 1936, Serial No. 68,414

5 Claims.

This invention relates to improvements in ventilating systems and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The invention is more especially concerned with that type of ventilating system including an air delivery duct and a diffuser or deflector means at the discharge or outlet end thereof. Such systems are largely used in theatres or like places of public gatherings and the discharge or outlet end thereof is usually disposed niche of the upright walls thereof. In theatres, this discharge or outlet end is often disposed in that wall having the arched opening for the stage. Under normal temperature conditions, the associated blower runs at its maximum to complete an air change about every three minutes and deliver air as far back as the last row of seats in the auditorium.

For illustration pu pose, an auditorium having thirty rows of seats requires an apparatus having a 30,000 cubic foot of air capacity per minute. In

order to obtain proper distribution of this maximum quantity of air, through the usual difiusing means provided at the discharge end of the duct, said means must have a square foot area permitting the establishment of an air velocity approximating 1,500 feet per minute. With an outside air temperature of about a reduction in the volume of air delivered is necessary for the comfort of the patrons. A reduction of 50% of the maximum volume of air passing through such a dififuser will result in a drop in velocity to about 750 feet per minute and this velocity is insuihcient to carry the reduced volume to the rear rows of seats in the auditorium or to create the necessary air turbulence, or perceptible air motion, for comfort.

It is now the practice, when the temperature of the outside air which the blower delivers through the duct falls, to reduce the speed of the blower through its associated driving motor or otherwise. With such a procedure, the volume of the air, as well as its velocity, is reduced. Thus when the discharge end of the duct is positioned relatively high, the air discharged does not reach the back row of seats, but only reaches some intermediate row. Therefore, certain of the patrons in the rear of the auditorium feel little or no air movement, while others complain as to the coolness of the air delivered.

Thus by cutting down the velocity and volume of the air, certain objections arise. The ventilation is spotty, because certain portions of the auditorium are under-ventilated and warm, while other portions are over-ventilated, and too cool.

I am aware of prior patent, No. 2,021,408, of November 19, 1935, wherein a structure is shown for cutting down the blast volume without affecting the velocity. The structure in said patent, however, required some means to reduce blower speed. This, of course, reduced blast velocity and the damper type of equalizer therein, in response to reduced velocity, operated to restrict the area of the blast discharge. This substantially restored the velocity. Thus, even though volume was reduced, velocity remained substantially constant. However, even with the advantages gained in this respect, the structure therefore requires the-use of certain variable speed mechanisms between the blower and driving motor, along with devices for regulating or controlling'the speed mechanisms. Such mechanisms and devices, not only increase the cost of installation, but require manual attention for actuation and are apt to get out of order.

One of the objects of the present invention is to provide an improved means in the discharge end of the duct, whereby the efiective area of said end may be reduced or increased as necessary, and the static pressure in the duct varied in proportion, so as to be reflected in the dynamic pressure of the blower supplying the air blast. Thus no governor mechanism, speed controls, variable grip clutches or other devices are required in connection with the blower and its driving motor, resulting in a great saving in cost in installation and maintenance.

Another object of the invention is to provide an improved structure at the discharge end of the duct which is automatically operative in response to temperature changes, to reduce the eifective area of said discharge end, to cut down the volume of the blast discharged without substantially reducing its velocity.

Still another object of the invention is to provide a structure of this kind including an equalizer plate, the angle of which may be changed to control the effective area of the discharge end of the duct, while affording a straight line movement of one end of the plate, as near as possible to the extremity of said end to eliminate such space as would permit of an expansion of the blast before it .leaves said extremity.

The above mentioned objects of the invention, as well as others, together with the several advantages thereof, will more fully appear as I proceed with my specification.

In the drawings:

Fig. 1 is a longitudinal vertical sectional view through a part of a theatre building showing the installation therein of the improved ventilating system, embodying one form of the invention.

Fig. 2 is a perspective view of the equalizer casing of the system, removed from other parts associated therewith and with the equalizer plate in a position providing the full volumetric area for the discharge of a blast of maximum volume. Fig. 3 is a longitudinal vertical sectional view through the equalizer casing and associated duct end and diffuser on an enlarged scale and illustrates in full lines, the position of the equalizer plate in providing the approximate minimum discharge area for said casing and illustrates in dotted lines other positions of the equalizer plate providing intermediate discharge areas.

Fig. 4 is a detail horizontal sectional view on an enlarged scale through a part of the equalizer casing and associated parts as taken on the line 59-6 of Fig. 3.

Fig. 5 is a perspective view of a certain block employed in connection with the equalizer plate and which will be more fully referred to later.

Fig. 6 is a detail vertical sectional view through a part of the apparatus of the system as taken on the line 66 of Fig. '7.

Fig. 7 is a detail vertical sectional view through a part of the apparatus of the system as taken on the line 'll of Fig. 3.

In general, my invention contemplates the provision in the discharge end of the air duct of a ventilating system, in close proximity .to the air difiuser employed therewith, a damper-like equalizer plate or member which may be moved by temperature controlled means, into positions varying the volumetric area of said discharge end.

' This member is so arranged as to close off successive portions of said end, from the bottom upward, its limit of such volumetric area reduction being about 60% of the entire area or about three fifths of the entire height of said end.

When the said member is in a position closing off areas of said discharge end, between the maximum and the minimum, it is apparent that the volume is reduced in proportion,

Referring now in detail to that embodiment of the invention, illustrated in the accompanying drawings and especially to Fig. 1, l0 indicates a building, such as a theatre; Ii indicates the floor thereof and i2 and i3 indicate certain upright walls thereof. Forward of the wall I3 which may be in line with the front of the stage, is the auditorium Hi. At a desired elevation above the floor H is the floor H of the blower room 56. In the wall I2 is a louvered opening H for the entrance of outside air into the blower room.

In said room is a blower I8 driven by a motor Hi. In this case, the blower includes a casing 20 with aside inlet and a bottom horizontal discharge H. In the casing is the usual impeller wheel. The discharge 2| of the blower casing is connected by a duct 22 with a casing 23. For future reference, I term the same an equalizer casing because within the same is means operable to change the volume of the blast discharged without materially affecting the velocity thereof. This casing is arranged in line with an opening 24 in the wall l3, and forms the discharge end for the duct 22. As shown herein, the duct 22 is rather short. In certain instances, where the blower room is located in the basement of the theatre or on the roof of the theatre, the duct, of course, between the blower and the equalizer casing, may be of considerable'length. It is apparent that the longer the duct and the greater the number of bends therein, the greater is the static pressure operating as a resistance against the dynamic pressure of the blower and to the blast action thereof. In the conventional sys-' tems, this is reflected in the velocity of the blast that is discharged from the system.

As shown herein, the equalizer casing is of a rectangular cross section. It includes upright side walls 25 and horizontal top and bottom walls 25-27, the latter being spaced a short distance above the blower room floor l5. At the front end of the respective walls of the equalizer casing is a structural frame 28 of angle or like bars. Along the upright side members of this frame, at the front end thereof, are guide grooves 29 and along the junction of the side walls with the bottom walls are channel-like grooves 30. The purpose of said grooves will soon appear.

It is apparent that the casing has substantially the same cross section and volumetric area as the blower casing discharge. Thus under certain conditions, when the blower is in operation the maximum volume of the air blast at the maximum velocity may be delivered into the auditorium. However, assume that outside air is being taken into the blower room through the louvered opening H in the wall I2. Should the temperature of such air drop, it is apparent that a lesser volume of air is required for cooling and ventilating the auditorium.

To meet all conditions, I provide means in the casing 23 for changing the area of the discharge end of the casing without materially reducing the velocity of the blast. It is apparent that if the desired reduced volume be attained only by reducing velocity through lower blower speed, certain portions at the rear of the auditorium would be without perceptible air motion. The reason, therefore, is of course that the blast cannot carry as far back as desired, due to such reduced velocity.

The means before mentioned for reducing volumetric area of the discharge end of the duct, as defined by the outlet of the equalizer casing preferably constitutes an equalizer plate or member 32. This plate or member is of a width and length approximating the width and length of the casing and said length may be less than the height of the casing. The rear end of the member 32 is provided at each side with rollers 33 which run in the guide grooves 30 before mentioned. The front end of said member carries a shaft 32a on the ends of which are rollers 32b which run in -the grooves 29 for guided movement. Rotatively mounted on said shafts, near said rollers are cable clamping blocks 3Q, one of which appears in perspective in Fig. 5. When the rollers move up or down in the guide grooves 29 and when the rollers 33 move longitudinally in the guide grooves 30, it is apparent that the front end of the plate or member 32 will travel in a straight line perpendicularly and the rear end will travel in a straight line horizontally. The angle which said member assumes, of course, is determined by the position of its front and rear ends in their respective grooves.

The said equalizer plate or member 32 is so proportioned with respect to the casing that in one instance it will lie substantially fiat upon the bottom of said casing as shown in Fig. 2. At this time the full volumetric area of the casing is available for the discharge of the air blast in the duct at the maximum velocity.

When the front end of the equalizer plate or member is in its highest position, it will extend at an angle of about 45. This will close of! approximately 60% of the volumetric area of the discharge end of the casing, from the bottom and upward thereof, leaving a volumetric. area of only 40%, available or operative for discharge purposes.

. percentages maybe varied as desired by changing that this movement be produced mechanically and occur at the time of and be controlled by the change in temperature in the auditorium. As shown herein, the means for moving said member is as follows:

Extending transversely of the front end of the top wall of the equalizer casing is a cross shaft 35. This cross shaft is journalled in suitable brackets 36 on the top wall 26 of the casing and on each end of this shaft is a drum 31. On oneend of said shaft 'is a pinion 38. At the bottom 01' the front end of the casing are pulleys 39, one

- in line with and for each drum. Each pulley is carried by one end of an arm 39a, the other end of which is pivoted in a channel bracket 3% fixed to the bottom wall of the casing. On this arm, near the front end thereof is a block 390 having an inclined face adapted to be engaged by a wedge block lli mounted on a spring pressed screw 40a. A cable ti is wrapped around each drum 3'! and 0 one end of each cable extends down through an opening in the top wall of the casing and is then inserted in a hole 34a in the associated block 3d;

The other end of each cable passes through suitable openings in the top and bottom walls of the casing and is then wrapped around the asso ciated pulley 39. extends up through another opening in the bottom Wall of the casing so as to be inserted in the hole 3% in the associated block 36. A screw 352; (see Fig. 4) carried by the block 34, secures'the ends of said cables to the respective blocks. By means of the spring pressed screws Add, the arms 3% are held depressed to tension the cables.

When the shaft 35 is rotated in one direction or the other, it is apparent that the front end of the plate or member 32 will move upwardly or downwardly in a straight line with respect to the grooves 29. This closes off the desired bottom part of the discharge end of the casing and controls the volumetric area thereof.

To drive the shaft 35 in the proper directibn, I provide an electric motor 62. This motor is of a kind including a shaft that rotates slowly through a predetermined number of. degrees, backward and forward. Such motors which operate on low voltage, supplied from a trans former, may be purchased in open market and are designed to provide mechanical motion in true proportion to the demand of temperature. A motor of this kind, known as and made under the trade name of Modutrol Motor is well.

It is apparent that these maximum The end of each cable thenthat said gear meshes with and drives the pinion 38 on the shaft 35.

The motor 42 is electrically connected to and is controlled by a thermostatic switch.43' centrally arranged at a convenient point in the auditorium. If desired, instead of the thermostatic switch, a manualy operable motor controlling switch may be used. Therefore, should the temperature in the auditorium be suchas to require an air change, said switch will cause energization of the motor 42. Thus the equali'zing plate or member 32 will open up or close off the discharge end of the casing, as the case may be.

It is, of course, apparent that some means is desirable for diflfusing the issuing air blast so that it will be distributed evenly over the auditorium. Therefore, it is advisable to use a diffuser of the kind shown in the Feinberg and Halvorsen patent, No. 1,601,815 of October 6, 1926. Such a diffuser includes sets of deflectors whereby the blast of air may be directed both horizontally and vertically. In the structure of said patent, the louver-like deflector blades are i set as to angularity and are changed manually.

In the present instances, I employ the principles of the diffuser shown in the Feinberg and Halvorsen patent before referred to.

As shown herein, 45 indicates a rectangular diffuser casing secured to the front end of the casing 23 and arranged in an opening 2d provided therefor in the wall l3. In said casing are provided inner and outer sets of louver-like deflectors 48- Preferably, the deflectors of the inner set are arranged horizontally and the deflectors in the outer set are arranged vertically. These deflectors are pivotally mounted at their ends in the associated walls of the diffuser casing so that they may be disposed at those relative angles providing the best diffusion of air.

In the operation of the structure as described, assume that the plate or member 32 is disposed flat at the bottom of the equalizer casing 23 as shown in Fig. 2. With the blower in operation, the maximum area for the discharge of the blast of air, is available at the end of said casing and the diffuser 45. The direction of the blast is indicated by arrows in Figs. 2 and 3 respectively. Assumenow that the temperature in the auditorium drops so as to require a reduction in volume of air delivered into the auditorium. By reason of the thermostatic switch $3 in the auditorium, the motor M is energized and starts into operation. This will drive the shaft 35 through as much of a revolution as will bring the rollers 32b into the desired position in the grooves 29. The member 32, therefore, moves'into a position closing ofl a predetermined bottom portion of the discharge end of the casing 23, so that the effective area of the discharge is reduced to result in a reduction in volume.

With the change in volumetric area for the blast discharge, the static pressure in the duct changes therewith so as to be reflected in the dynamic pressure of the blower. Thus, while volume is reduced, velocity remains substantially constant because the blower cannot take in more air than it can pass through the duct and the now restricted area of the discharge end of the casing 23. As the reduced volume of blast passes through the difiuser, it is directed by such portions of the louvers iii-t1 as are efiective to cooperate with so much of the discharge area as is in actual use.

Assume now that the temperature in the audi- F5 .torium is again reduced. This will through the switch t3 energize the motor 32 to cause the plate or member 32 to be swung into a position further closing off the discharge end of the casing 23. In this position of the parts, the effective volumetric discharge area is further reduced, the static pressure in the duct is increased so as to be reflected in a reduction of air taken in by the blower. With the member 32 in its new angular position, it acts as a steeper deflector for the bottom portion of the blast being discharged.

Should the temperature in the auditorium again drop, the member 32 swings into its maximum angular position which gives the greater reduction of volumetric area for discharge. position, of course, further increases static pressure which is reflected in a further reduction of the air intake of the blower so thatwhile the volume may be reduced, the velocity remains substantially constant.

When the temperature in the auditorium rises, this will through the thermostat d3, energize the motor 52 to run in the other direction to cause such movement of the member 32 as will increase the area of discharge. In this movement of the said member 32 into a further open position, the static pressure becomes correspondingly reduced and the blower can take in more air for an increase in blast volume.

It is apparent that with the arrangement described, when the volume of the blast is reduced or increased, the velocity of the blast remains substantially constant. Thus efiicient ventilation is provided in connection with different temperature changes in the space being ventilated.

Again, it is apparent that no expensive appliances are necessary for changing blower speed to accord with volume, the change being made by the action of static pressure in the duct.

While in describing the invention, I have referred in detail to the form, arrangement and construction of certain of the parts thereof, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto except as may be specifically pointed out in the appended claims.

I claim as my invention:

1. In combination with the discharge end of the air duct of a ventilating system and including top, bottom and side walls, a member in said end of the air duct for controlling the efiective area thereof, means on one end of said mem her and on said side walls respectively, whereby said one end may be moved in a guided vertical path to control the area of said discharge end,

and means providing a guided movement for the other end of said member along the bottom wall in a plane substantially at a right angle to said first. mentioned path.

2. In combination with the discharge end of the duct of a ventilating system, a member in said duct and having an end formed for a. straight line guided engagement with opposite walls of- This the duct and having another end formed for a straight line guided movement with respect to another wall of the duct in a plane substantially at a right angle to the first mentioned line, and means for moving the first mentioned end of said member in said straight line, said means including a shaft, a wheel thereon and means connecting said wheel with saidfirst mentioned end of said member.

3. An equalizer structure for use in connection with the discharge end of the air duct of a ventilating system comprising a rectangular, open ended casing and including top, bottom and side Walls, means in said casing for controlling the efiective area of said casing and comprising a plate-like member, means providing a guided horizontal movement for the rear end of said member, means providing a vertical path of movement for the front end of said member with respect to the side walls of said casing, and means operatively connected to a part of said last mentioned means for causing movement of the front and rear ends of the member in said paths at substantially a right angle to each other in either direction.

4. An equalizer structure for use in connection with the discharge end of the air duct of a ventilating system comprising a rectangular, open ended casing and including top, bottom and side walls, means in said casing for controlling the efiective area of said casing and comprising a plate-like member, means providing a guided horizontal movement for the rear end of said member, means providing vertically disposed guides on the front end of said side walls, means carried by the front end of said member and having engagement with said guides, and means for imparting movement to said plate-like member so that said front end moves parallel with said guides and in a plane substantially at a right angle to the rear end.

5. An equalizer structure for use in connection with the discharge end of the air duct of a ventilating system comprising a rectangular, open ended casing and including top, bottom and side walls, means in said casing for controlling the efiective area of said casing and comprising a plate-like member, means providing a guided horizontal movement for the rear end of said member, means providing vertically disposed guides on the front end of the side walls of the casing, rollers on the front end of the said memher and engaged in said guides, a horizontal shaft mounted on the topwall of the casing, annular members on said shaft, pulleys arranged below the bottom wall of said casing, flexible members trained about said annular members and pulleys respectively'and operatively connected to the front end of said plate-like member, and means for rotating said shaft in the desired direction.

JOHN R. HALL.

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