US2345536A

US2345536A - Heat exchange unit

Info

Publication number: US2345536A
Application number: US443203A
Authority: US
Inventors: Charles R Keep
Original assignee: BF Sturtevant Co
Current assignee: BF Sturtevant Co
Priority date: 1942-05-16
Filing date: 1942-05-16
Publication date: 1944-03-28
Anticipated expiration: 1961-03-28

Description

4March 28, 1944. c. R KEEP 2,345,536

HEAT EXCHANGE UNIT Filed May 16, 1942 Pneaaa 2s, 1944 2,345,536 HEAT EXCHANGE UNIT Charles B. Keep, Norwood,

Stnrtevant .Commun Mass., assigner to B. F.

Boston, Mass.

` Application May 1c, 194g, serial No. .443,203 4 claims. (ci. 257-137) This invention relates to heat exchange units oi the type which contain air ejector nozzles through which primary air from a central source is supplied for inducing the ilow into the units, of recirculated air.

'I'he copending Palmer Patent No. 2,287,2674

which issued June 23, 1942 discloses such a unit in which the external surfaces of the heat exchange tubes are shaped and arranged to form the ejectors for inducing the ilow of recirculated air. The present invention provides improve' ments over the features disclosed -in said application and which modify 'same for overcoming diillculties of commercial operation.

A feature of this invention resides in providing for varying the induction effect of ejector nozzles utilizing surfaces of heat exchange tubes. In one embodiment of the invention this is'accomplished Vby using an elongated heat exchange tube as one wall of an ejector nozzle, the other wall being provided by a pivoted sheet metal member which isv adjustable about its pivot for varying the spacing between the ejector walls and thus varying the ejector eifect. In another embodiment of the invention, the ,opposite wallsof the ejector nozzle are formed by elongated heat exchange tubes', one or both of the tubes having extensions at the tips thereof and one of the extensions being pivoted for varying the spac' g between the nozzle tips and thus varying the ejector eiect.

Another feature of the invention resides in providing an air by-pass around an ejector nozzle which includes one or "more heat exchange tubes as an element or elements thereof. In one em' bodiment of the invention an air by-pass is 'provided within a. unit, around an air ejector nozzle utilizing a heat exchange tube as one wall. In

another embodiment of the invention utilizing heat exchange tubes as opposite walls of an ejector nozzle, an air by-pass is provided by utilizing two recirculated .air inlets, Yone below and the other above the ejector.

Objects of the invention are to improve the eiicicncy of and to reduce the cost; of, heat exchange units of the type which include ejector nozzles for inducing the ilow of recirculated air.

'I'he invention will now be described with reference to the drawing, of which:

Fig. 1 is a cross sectional view through one embodiment of a heat exchange unit incorporating features of this invention;

Fig. 2 is a cross sectional view through another embodiment of a heat exchange unit incorporating features of this invention, and

Fig. 3 is a side elevation of the unit of Fig. 2.--

Referring first to Fig. 1, the heat exchange unit there illustrated has the lower wa1l'5, the opposite side walls 6 and the upper wall 1. One of the side walls i has a recirculated air inlet opening 8 in its lower portion, and the upper wall 1 contains.

the discharge outlet 9.

'I'he elongated heat exchange tube III forms with the sheet member II, a converging, upwardly extendingnejector nozzle. 'Ihe vertical walls I2 connect with the lower ends of the tube lll and the member II and together with the lower wall I3 form a primary air passage which connects through one end wall of the unit, with the primary air duct I I.

The duct Il is adapted to be connected to a cen- Y tral source of prima conditioned air under sufficient pressure for the ejector nozzle formed by the tube I0 and the member Il to induce desired volumes of recirculated air through the inlet/8 and for the mixed primary and recirculated air to be discharged at suiiicient velocity and under suflicient pressure to convey the discharged air to points in the space served, remote from the unit.

A plurality of closely spaced extended surface ns'l5 extend from the surface of the tube Ill opposite the member Il, to one of the vertical walls 8 of the unit. A' pivoted damper I6 is provided at the lower end of the tube I8 and is adjustable to open up orto close the recirculated air passage from the inlet 88 through the ilns I5.

A second pivoted damper I1 extends between the wall I2 contacting the lower end of the member II, and the other wall 6 of the unit and is adjustable to close off or open up the recirculated air passage on which it is mounted. This recirculated air passage is seen to be a passage bypassing the heat exchange surfaces formed by the tube I0 and the iins I5.

'I'he dampers I6 and Il are pivoted in the end walls of the unit and supported thereby by means well known in the art.

'I'he tube I0 has an internal opening I8 for the passage of a heat exchange medium for tempering the primary and recirculated air. In hot weathenra chilled brine or other suitable iluid may be passed through the tube Il! for cooling the air. In-cold weather, steam or hot water may be passed through the tube l0 for heating the air.

The lower end of the member II is pivoted at etc., and is not again adjusted unless conditions change. The dampers IS and I1 are adjusted for varying the volume of recirculated air which passes in contact with the heat exchange surfaces VVI0 and I5 and for Varying the volume of bypass air, it being preferred that the total discharge volume remain constant throughout the entire range of adjustment. By varying the proportion of heated recirculated air to bypass recirculated air local heat requirements can be satisfied without adjustment of the primary air 'supply or the heat exchange iluid supply.

The unit ofFig. 2 is similar to that of Fig. 1 in many respects and the same reference characters are applied to similar components. However, instead of having a sheet metal forming one wall of the ejector nozzle, in Fig. 2, two similar tubes I provide the opposite, conmember ,Y

verging walls of the ejector nozzle, both tubes the fins l5 which extend from the outer surfaces of the tubes to the walls 6. In the unit/ of Fig. 2 all of the recirculated air from the inlet 8 passes in contact with the fins .I 5.

A bypass around the heat exchange surfaces, for recirculated air is provided by another re- |0 being provided with circulated air inlet 22 placed between the tubes ber being pivoted at its end opposite the tip of the nozzle for varying the spacing between the nozzle tips and thus varying the induction effect, and means forming a passage conducting air from said primary air inlet into said nozzle and'forming walls isolating air from said recirculated air inlet from the air from said primary airinlet.

2. A heat exchange unit having a primary air inlet, a recirculated air inlet and a discharge outlet for the mixed primary and recirculated air, an elongated heat exchange tube forming one wall of an ejector nozzle for inducing the flow of air through said recirculated air inlet, said tube having an internal opening for the passage of wheat exchange medium, a member of sheet material arranged alongside said surface and spaced therefrom and forming the other wall of said nozzle, said member being pivoted at its end opposite the tip of the nozzle for Varying the spacing between the nozzle tips and thus varying the induction eifect, and means forming a passage conducting air from said primary air inlet into said nozzle and from said recirculated air inlet 4from the air from The ejector nozzle adjustment lin the unit of Fig. 2 is taken care of byl attaching the stationary plate extension 2l to the upper end of one of the tubes l! and by pivoting the plateextension 28 to the upper end of the other of the tubes. The rod 29 is attached to the plate 28 and is moved by the knob 30 for varying the space between the

plates

21 and 28 and accordingly the air inducing eiect of the nozzle. The subject matter of Fig. 2 is claimed in applicants copending divisional application, Serial No. 471,048.

The pipe 3| illustrated by Fig. 3, may be a pipe for conveying heat exchange fluid to the tubes I0.

A side -elevation of Fig. 1 would be similar to Fig. 3 except, of course, that the upper recirculated air inlet 22 would be omitted, the knob 30 would be omitted and the lower inlet 8 would appear larger.

Advantages of utilizing the surface of an elongated tube lll as an ejector wall are that saving in material results; that improved heat transfer is obtained due to the absence of the turbulence and the shadow effect of round tubes; the operation is quieter, the efficiency is greater and the elongated tubes and their ns may be cast iron, a material more easy-,to obtain than copper under emergency conditions.

While embodiments of the invention have been described for the purpose of illustration, it should be understood that theinvention is not limited to the exact apparatus and arrangements of apparatus illustrated, as modications therefrom may be suggested b y those skilled in the art without departure from the essence of the invention.

What is claimed is:

1. A heat exchange unit having a primary air inlet, a recirculated air inlet and a discharge out- -let for the mixed primary and recirculated air,

an elongated heat 4exchange tube forming one wall of an ejector nozzle for inducing the ow of air vthrough said recirculatedair inlet, said tube having an internal opening for the passage of a heatA exchange medium, a member arranged alongside said surface and spaced therefromand forming the other wall of said nozzle, said mem- 7 material arranged alongside said surface and spaced therefrom and forming the other wall of said nozzle, said member being pivoted at its end opposite the tip of the nozzle for varying the spacing between the nozzle tips and thus varying the induction effect, and means forming a passage conducting air from said primary air inlet into said nozzle and forming walls isolating air from said recirculated air inlet from the air from said primary air inlet, said recirculated air inlet being contained Within one wall of said unit and said member being spaced from the opposite wall thereof and providing a by-pass therebetween for air from said recirculated air inlet to said outlet, around said tube.

4. A heat exchange unit having a primary air inlet, a recirculated air inlet and a discharge outlet for the mixed primary and recirculated air, an elongated heat exchange tube forming one wall of an ejector nozzle'for inducing the flow of air through said recirculated air inlet, said tube having an internal opening for the passage of a heatlexchange medium, a member of sheet material arranged alongside said surface and spaced therefrom and forming the other wall of said nozzle, said member being pivoted at its end opposite the tip of the nozzle for varying the spacing between the nozzletips and thus varying the induction effect, and means forming a passage conducting air from said primary air inlet into said nozzle and forming walls isolating air from said recirculated air inlet from the air from said primary air inlet, said tube having extended surface ns extending from its external i said outlet, around said tube and said fins.

CHARLES a. KEEP.-

forming walls isolating air-