US3374831A - Blower diffuser - Google Patents

Description

March 26, 1968 w. F. SIEVERDING BLOWER DIFFUS ER 2 Sheets-Sheet 1 Filed Jan. 25, 1966 INVENTOR WAYNE E SIEVERDING BY 9/ flu. ?/w

' ATTORNEYS FIG I FIGZ March 26, 1968 w. F. SiEVERDING BLOWER D IFFUS ER 2 Sheets-Sheet 2 Filed Jan. 25, 1966 FIG4 INVENTOIR WAYNE F. SIEVERDING BYZZ/A *M ATTORNEYS United States Patent Ofifice 3,374,831 Patented Mar. 26, 1968 3,374,831 BLOWER DIFFUSER Wayne F. Sieverding, Union Grove Lake, Iowa, assignor to Lennox Industries Inc., a corporation of Iowa Filed Jan. 25, 1966, Ser. No. 523,508 3 Claims. (Cl. 165-122) ABSTRACT OF THE DISCLOSURE An air treating device including a blower, a heat exchanger downstream of the blower, and a blower diffuser disposed at the outlet from the blower for converting the velocity energy of the air to static energy for improving the heat transfer of the air as it passes over the heat exchanger.

This invention relates to a diffuser for a blower as used, for example, in air treating apparatus, wherein it is desired to reduce the velocity of the air discharging from the blower in a relatively short distance prior to passage of the air over a heat exchange member.

Heretofore, it has been known to utilize a screen or perforated plate to reduce the velocity of air discharging from a blower prior to passage of such air over a heat exchange member, as for example, a furnace heat exchanger or an evaporator coil. Prior arrangements have not been entirely satisfactory, for often when the blower is spaced closely adjacent to the heat exchange member, there is excessive back pressure created in the blower and blower operation is impaired. In some applications, if no means are provided for reducing the velocity of air discharging from the blower and the blower is disposed closely adjacent to a heat exchange member, the air will rush through the heat exchange member with a minimum of heat exchange. Further, in the case where the heat exchange member is a cooling coil, air traveling at high velocity may concentrate over the center of such cooling coil and adversely affect the operation of the control valve commonly used to control the passage of refrigerant through such cooling coil. In one air treating unit in use today, where blowers are utilized to pass air over a heater and a cooling coil disposed in side-by-side relationship and the heater and cooling coil are operative at the same time, in the event that there were substantial demand for cooling and the air were discharged from the blower at a high velocity, then with the mixing damper associated with the heater closed, much of the air passed over the heater would be recirculated and passed over the cooling coil, thus reducing the eificiency of the cooling coil.

An object of the present invention is to provide an improved blower diffuser between a blower and a heat exchange member, such blower diffuser comprising a plurality of diverging nozzles for converting velocity energy to static energy in a relatively short distance so as to minimize the distance required between the blower and the heat exchange member associated therewith without adversely affecting heat transfer of air passing over the heat exchange member or impairing blower operation.

Other objects and advantages of the present invention will be made more apparent hereinafter.

The specific structural details of the invention and their mode of operation will be made most manifest and clearly pointed out in clear, concise and exact terms in conjunction with the accompanying drawings, wherein:

FIG. 1 is a fragmentary perspective view of an air treating unit embodying the blower diffuser of the present invention;

FIG. 2 is an enlarged side view of the blower diffuser of this invention, with the parts being broken away;

FIG. 3 is a cross-sectional view through the blower diffuser, taken generally along the line 33 of FIG. 2; and.

FIG. 4 is a front view of the blower diffuser of this invention.

Referring to FIG. 1, there is shown in perspective a portion of a Lennox DMS air treating unit embodying the present invention. The air treating unit 10 includes an enclosed frame 12 having defined therein chambers 13 and 14, respectively, for receiving outdoor air and recirculated air. Blowers 15 and 16 draw the air from the chambers 13 and 14 through the damper openings and force the air over the cooling coil 17 and heat exchanger 18, respectively. The blowers 15 and 16, which may be of the centrifugal type, are driven by a blower motor 20 resiliently supported on the frame 12 and operatively connected to the blower shaft 21 by means of a belt and pulley drive 22. The air treating unit per se is not part of this invention and reference may be made to the copending Norris and Sieverding application Ser. No. 421,427, filed Dec. 28, 1964, now Patent No. 3,324,782, granted June 13, 1962, for a fuller description thereof.

As seen in FIG. 1, the outlet from the blowers 15 and 16 is spaced relatively closely adjacent to the cooling coil 17 and the heat exchanger 18. The heat exchanger 18 may be gas or oil-fired, though it will be understood that other suitable heaters may be utilized, as for example, an electrical resistance heater. In the absence of the blower diffuser or velocity pressure converter of the present invention, high velocity air discharging from the blowers 15 and 16 would pass through the cooling coil 17 and the heater 18 Without affecting optimum cooling or heating of the air. In addition, high velocity turbulent air flow over the cooling coil could cause erratic hunting of the thermal expansion valve commonly utilized to control the flow of refrigerant to the evaporator or cooling coil 17. Furthermore, in certain periods of operation, high velocity air impingement forces air partially through the heater, which then recirculates back to the cooling coil, adding substantially to the cooling load.

T o overcome the difiiculties noted above, there is provided by this invention a blower diffuser or velocity pressure converter 24, closely adjacent the discharge from each blower to convert the kinetic energy of the high velocity blower discharge to static pressure so as to produce nearly laminar air fiow between the outlet from the blower diffuser and the associated cooling coil 17 or heater 18. The blower difiusers 24 and 25 include frame means defining a plurality of diverging nozzles for converting velocity energy to static energy in a relatively short distance.

Turning now to FIGS. 2, 3 and 4, there is better illustrated constructional details of the blower diffuser or velocity pressure converter of the present invention. Each blower diffuser 24, 25 includes a housing 30 having top and bottom walls and spaced side walls. The opposed wall members diverge away from one another from the inlet 32 of the housing 30 to the outlet 34 from housing 30. Flanges 36 are provided on the housing adjacent the inlet end for permitting affixation of housing 30 to the upright frame 38 in the air treating unit 10. Suitable fastening means 37 are provided for securing the blower diffuser 25 to frame 38. The scroll or housing 40 of the fan or blower 16 is suitably afiixed to the frame support 38. The outlet 42 from the blower is complementary to the inlet 32 to the blower diffuser and is in juxaposition as shown in FIG. 2. It is apparent from FIGS. 2, 3 and 4 that the cross-sectional area of the inlet 32 to housing 30 is less than the cross-sectional area of the outlet 34 from housing 30.

Provided within housing 30 are a plurality of upright 3 wall'members 45, 46, 47, 48 and 49. Disposed transversely of the wall member 45-49 in the housing 30 are a plurality of wall members 50, 51, 52 and 53. The wall members may be made from sheet metal. The transverse wall members may be suitably notched or cut to provide for interengagement of the respective upright and transverse wall members so as to provide a cluster of diverging nozzles 54-83. The diverging nozzles are substantially of uniform configuration.

In the illustrated embodiment of the invention, each wall member 45-49 and 50-53 is provided with a flange at each end which is adapted to be suitably affixed to the sides, top and bottom, respectively, of housing 30. Preferably, each of the nozzles 54-83 is a diverging 7%. degree nozzle. 1

Referring to FIGS. 2 and 3, it is noted that the wall members 46, 47 and 48 are each provided with extensions 46a, 47a and 48a, respectively. The extended portion of 7 these wall members pass through the inlet 32 to the blower diffuser and into the outlet 42 from the blower for better distributing the air entering the blower diffuser from the adjacent blower.

In one form of the present invention adapted to be utilized for a 12-inch or 15-inch blower, the inlet opening of the blower diffuser is substantially rectangular and is about 11 7 x 18 4 inches. The outlet opening from the blower diffuser is similarly a rectangle about 28 ,4 x 17 ,5 inches. The walls defining each nozzle 54-83 are constructed and arranged so as to define approximately 7 /2 degree diverging nozzles.

In this form of the invention, the longitudinal length of the housing from the inlet to the outlet is about 8 inches. Thus, the velocity of the air discharged from the blower is substantially reduced within an axial distance of about 8 inches. The flow of air from the outlet of the blower diffuser of this invention is substantially laminar. In effect, a static pressure area is provided at the outlet from the blower diffuser. Thus, the heat exchanger, either the cooling coil or heater, may be disposed about two feet from the outlet of the blower diffuser while obtaining optimum heat transfer and without adversely affecting blower operation. For example, it has been found that a typical centrifugal blower having a wheel diameter of 15 inches and having a velocity pressure of 1.55 inches water gauge at the inlet to the diffuser (at the outlet from the blower) will have a velocity pressure of 0.35 inch water gauge at the outlet from the diffuser. Further, it has been found that there is a greater negative velocity pressure at the blower outlet when the novel blower diffuser of this invention is used. This, in turn, results in improved blower performance.

The present invention provides a blower diffuser which is essentially a cluster of highly sophisticated diverging nozzles, in front of each blower, for converting the kinetic energy of the high velocity blower discharge to static pressure to produce nearly laminar airflow at the blower diffuser outlet. Thus, the heat'exchanger used with the blower can be positioned relatively closely adjacent to the blower diffuser outlet with assurance that desired heat transfer will occur. The blower diffuser has application in an air treating unit asillustrated, for example, in FIG. 1 and also has utility in many other applications, as for example, in a furnace where it is desired to place a high-speed blower closely adjacent to a gas or oil-fired heat exchanger or to an electric resistance heater.

While the invention has been described with reference to a preferred embodiment thereof, it will be appreciated that it may be otherwise embodied within the scope of the following claims.

Iclaim:

1. In an air treating device, the combination of a blower, a heat exchanger and a blower diffuser, said blower having a housing with inlet and outlet means, said heat exchanger being disposed relatively closely adjacent said blower downstream of said diffuser and said blower, said blower diffuser having a housing with an inlet and an outlet, the inlet of said diffuser being complementary to the outlet means of said blower andin juxtaposition thereto, the cross sectional area of the outlet of said diffuser being greater than the cross sectional area of the inlet of the diffuser, said diffuser including a cluster of diverging nozzles within thehousing thereof, whereby the nozzles convert velocity energy to static energy in a relatively short distance and the flow of air from the outlet of the diffuser housing is substantially laminar and of reduced velocity, thereby enhancing heat transfer as the air passes over the heat exchanger down-stream of the diffuser and blower.

2. An air treating device as in claim 1 wherein the blower includes a centrifugal fan, the blower diffuser providing a relatively greater negative velocity pressure at the blower outlet so as to improve blower performance.

3. An air treating device as in claim 1 wherein a plurality of upright and transverse wall members provided within the housing define the cluster of diverging nozzles, said nozzles being of substantially uniform configuration, with the wall members forming each nozzle diverging from the entrance to the exit of each nozzle about 7 /2 degrees.

References Cited UNITED STATES PATENTS 1,903,777 4/1933 Coin -5 98-40 2,106,458 1/1938 Kurth 9840 3,185,181 5/1965 Demyan 98-40 3,324,782 6/1967 Norris et al. 9833 ROBERT A. OLEARY, Primary Examiner. T. W. STREULE, Assistant Examiner.

Images