CA1323866C - Transport cargo heater - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A transport cargo heater for heating the air in a served space via the liquid coolant of a liquid cooled internal combustion engine, and by churning and compression of the air by air delivery means. The air delivery means draws air from the served space and returns it to the served space via a liquid to air heat exchanger. An engine water pump functions to circulate the engine coolant through both the engine and the heat exchanger. A
monocoque support for the engine includes a three-point support frame and a cover rigidly interrelated such that engine mounting stresses are initially accommodated in horizontal and vertical planes, defined by engine support rails and a bulkhead, respectively, and transferred into the cover. The cover is rigidly attached to, and dissi-pates stresses into, the structure of an associated trail-er, which defines the served space.

Description

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1 54,234 TRANSPORT CARGO HEATER

BACKGROUND OF THE INVENTION
Field of the invention:
The invention relates to cargo heaters for heating the served space defined by transport apparatus, such as the trailer of a tractor-trailer unit.
Descri~tion of the_Prlor Art:
Certain types of loads hauled by trucks, such as perishable foods, require air conditioning apparatus having the capability of both heating and cooling, in order to maintain a selected temperature set point. Other tempera-ture sensitive loads, such as paints, chemicals, photo-graphic products, and the like, may require only a heat source during the winter months to maintain the temperature of a served spacQ- above a predetermined level, regardless of the outside ambient. The present invention relates to the latter type of air conditioning apparatus.
Accordingly, it-is an object of the invention to provide a reliable cargo heater which has a relatively low manufacturing cost. It should be economical to operate, and it should be small and compact, so it may be quickly added to a dry van, or quickly exchanged with a transport refrigeration unit of a reefer, when the need arises. The cargo heater should be able to withstand the vibration of highway travel without undue maintenance costs, and it should have the capability of uniformly heating long trailers, without hot spots, and without the problems 1323g~) assoclated with uslng exhaust gases from an lnternal combustlon englne as a heat Rourc~.
SUMMARY OF THE INVENTION
Brlefly, the present inventlon 18 a cargo heater for transport apparatus which heats the alr of a space to be served by agltation of the alr by a hlgh volume air dellvery unlt, preferably a centrlfugal blower, whlch assures that long trallers wlll be unlformly heated, and by heat re~ected by a dedlcated llquid cooled lnternal combustlon englne, preferably a Dlesel englne, whlch ls turned off to conserve fuel when heat ls not requlred. The conventlonal englne water pump serves the dual purpose of clrculatlng llquld coolant through the englne, to remove heat therefrom, and the same pump ls used to clrculate the heated llquld through a llquld-to-air heat exchanger which transfers heat from the coolant to alr forced through the heat exchanger by the air delivery means. A relatively low manufacturing cost is achieved by directly and rigidly mountlng the englne to a support frame having three mounting points for englne stablllty, and by directly and resillently mountlng the alr dellvery means to the englne drive means, ellminating shock mounts, pulleys, belts and the llke. Low maintenance is achieved, via the dlrect mountlng arrangements, and by a monocoque support arrangement whlch transfers engine mounting stresses from horlzontal and vertical engine mountlng surface planes to a cover which is lntegral wlth, and shares the stresses wlth, the englne structural support members. The support arrangement transfers mechanlcal stresses created ln the cargo heater lnto the structural wall of the traller the cargo heater is mounted on, B

132~
2a 73661-77 where the stresses are dlsslpated wlthout damaglng stress concentratlon.
In accordance wlth the present lnventlon there ls provlded a transport cargo heater for heatlng the alr of a served space whlch lncludes a vertlcal wall havlng an outer surface, comprlsing:
a support frame, sald support frame havlng three support surfaces ln vertlcal and horlzontal planes respectlvely deflned by a bulkhead, and flrst and second spaced englne support ralls, sald support frame further lncludlng front and rear rall members flxed to the flrst and second englne support ralls, sald bulkhead havlng flrst and second ma~or sldes, and an openlng havlng a central axls whlch extends between sald flrst and second ma~or sides, wlth the second ma~or side belng adapted for mountlng on the outer surface of the vertlcal wall of the served space, means flxing the rear rall member to the flrst ma~or slde of sald bulkhead, sald eng~ne support ralls each havlng flrst and second ends and longltudlnal axes disposed to lntersect the flrst ma~or slde of the bulkhead, an external cover, means rlgldly flxlng sald cover to said bulkhead and to at least the front rall member of the support frame, such that mechanlcal stresses ln the flrst and second support ralls are transferred to the bulkhead vla the front rail member and cover, and via the rear rail member, . .;. .
' .

1 ~, 2 `~

2b 73661-77 an internal combustlon englne havlng a llquld coolant, means rlgldly mountlng sald englne to said three support surfaces of the support frame, sald engine havlng drive means, lncludlng a drlve shaft, disposed to enter the openlng deflned by sald bulkhead, alr dellvery means dlsposed ad~acent to the second rna~or slde of the bulkhead, sald alr dellvery means belng dlrectly and reslllently flxed to the drlve shaft of sald englne vla a flexlble coupllng such that sald air dellvery means ls dlrectly drlven by the englne drlve shaft, a llquld to alr heat exchanger dlsposed ad~acent to sald alr dellvery means such that alr drawn from a served space by the alr dellvery means ls dlscharged through sald heat exchanger, and means provldlng llquld flow communlcatlon between sald heat exchanger and sald englne such that englne coolant transfers heat to alr passlng through the heat exchanger, addlng to heat ln the alr produced by agltatlon of the alr by the alr dellvery means.
BRIEF DESCRIPTION OF THE DRAWINGS
The lnventlon may be better understood and further advantages and uses thereof more readlly apparent when consldered ln vlew of the followlng detalled descrlp-~ ~ ) 2 ~3 ~ ~ ~

3 54,234 tion of exemplary embodiments, taken with the accompanying drawings, in which:
Figure 1 is a perspective view of a car~o heater, which may be constructed according to the teachings of the invention, shown mounted in its operating environment on the front wall of a trailer;
Figure 2 is a front elevational view of the cargo heater shown in Figure 1, without the access doors;
Figure 3 is a side elevational view, in section, of the cargo heater shown in Figure 2, taken between and in the direction of arrows III-III;
Figure 4 is a plan view, in section, of the cargo heater shown in Figure 2, taken betw~en and in the direc-tion of arrows IV-IV;
Figure 5 is a perspective view of an engine support frame shown in Figures 2, 3 and 4, which is dis-posed on one side of a support bulkhead, and of a blower and heat exchanger, which are disposed on the opposite side of the support buLkhead;
Figure 6 is a perspective view of a Diesel engine and its mounting support, ready for mounting on the engine support frame and bulkhead shown in Figure 5; and Figure 7 is a perspective view of the rear of the cargo heater, illustrating more clearly the portion of the cargo heater which fits into an opening in the front wall or nose of the trailer shown in Figure 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, and to Figure 1 in particular, there is shown a cargo heater 10 which may be constructed according to the teachings of the invention.
Cargo heater 10 is shown in its operating environment, mounted on the front wall 12 of a trailer 14. Trailer 14 defines a served space 15, which is to be conditioned, i.e., heated, by cargo heater 10. Cargo heater 10 is dimensioned such that it fits the same mounting bolt pattern, and same sized opening into the served cargo space 15, as a transport refrigeration unit for a reefer. A

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4 54,234 remote control box 16 locates operating controls and meters at a level which facilitates adjustment by the driver.
A cover 18 for cargo heater 10 is aerodynamically contoured for appearance and low air resistance, and two large hinged doors 20 and 22, which encompass substantially the entire front 24 of cargo heater 10, provide ea~y access to internal components of cargo heater 10 for maintenance purposes. Cover 18 includes a bottom 19, a top 21, and first and second upstanding sides 23 and 25, all of which smoothly flow or curve into the vertically oriented front 24, which is largely defined by access doors 20 and 22.
Cargo heater 10 is of monocoque construction, wherein cover 18, in addition to. providing a pleasing appearance and protecting internal components from the elements, is integral with, and shares stresses with, internal structur-al elements, as will be hereinafter described.
Figure 2 is a front elevational view of cargo heater 10 without doors 18 and 20, and before functional components are mounted therein, illustrating a support frame 26 which cooperates with cover 18 to transfer mechan-ical stresses into larger mass components for dissipation.
Suppor~ frame 26 provides support surfaces for an internal combustion engine 28 shown in perspective in Figure 6, with a Diesel engine being preferred.
Figures 3 and 4 are elevational and plan section-- al views taken in the direction of arrows III-III and IV-IV, respectively, in Figure 2, and Figure 5 is a per-spective view of support frame 26 without cover 18. All of these figures will be referred to, along with Figure 2, in the following description of support frame 26.
More specifically, as best shown in Figure 3, support frame 26 provides a stable three-point mounting arrangement for engine 28 in two orthogonal planes. Two of the mounting points lie in a horizontal plane 30, and the third mounting point is provided by a surface which lies in a vertical plane 32. The mounting surface in vertical plane 32 is provided by a steel bulkhead 34 having first ~ '`3 2 ~
54,234 and second major sides or surfaces 36 and 38, respectively.
The first major side 36 faces the front 24 of the cargo heater, i.e., it is within the cover 18 and accessible when doors 20 and 22 of the cargo heater 10 are opened, and the second major side 38 faces the front wall 12 of an associ-ated trailer 14. Bulkhead 34 defines an opening 40 having a central axis 41, which opening extends between major sides 36 and 38.
The mounting surfaces in horizontal plane iO a~e provided by additional structural steel elements of support frame 26 which include first and second spaced support rails 42 and 44, respectively, a front tubular support member 46, a rear support member 48, and a bulkhead tube 50. The first support rail 42 includes first and second ends 52 and 54, respectively, and a longitudinal axis 56 which extends between its ends. The second support rail 44 includes first and second ends 58 and 60, respectively, and a longitudinal axis 62 which extends between its ends.
The first support rail 42 includes an upper - 20 horizontally oriented support flange 64 having two steel mounting pads 66 and 68 welded o~ otherwise suitably attached thereto. A depending integral leg portion 70 extends downwardly from one side of support flange 64, and a depending web 70 extends downwardly from the opposite side. Web 70 increases its vertical dimension from~ the first end 52 to the second end 54, and an integral flange 74 extends outwardly from the lower end of web 72, in a direction opposite to the extension of support flange 64 from web 72. Leg portion 70 and web 72 are recessed back from the first end 52, allowing the upper support flange 64 to extend freely outward for a predetermined dimension for cooperation with front tubular support member 46.
The second support rail 44 is a mirror image of - the first support rail 42, having two steel mounting pads 76 and 78 secured to an upper support flange 80.
Front tubular support member 46 is an elongated steel tube having first and second ends 82 and 84 cut at an 1~,23~
6 54,234 angle to match the curving vertical side walls 23 and 25, respectively, of cover 18. Tubular member 46 is bent, as indicated by bend lines 90, 92, 94 and 96, for increased stiffness.
Rear support member 48, similar to all of the other structural support members and cover 18, is formed of steel, and it includes an elongated flat web 98 having outwardly extending flanges 100 and 102 at its longitudinal ends, and an outwardly extending flange 104 which extends along the bottom edge of web 98, between end flanges 100 and 102.
Support rails 42 and 44, and front and rear support members 46 and 48 are joined together and they are also fixed to cover 18, to form a strong box-like structure 106 in which the ends 82 and 84 of the front tubular member 46 are welded to the vertical s-ides 23 and 25 of cover 18.
The rear support member 48 is welded to bulkhead 34. The first ends 52 and 58 of the support rails 42 and 44, respectively, are welded to the front tubular support member 46, and the second ends 54 and 60 of the support rails 42 and 44, respectively, are- welded to the rear support member 48. Bulkhead tube 50 is welded to bulkhead 34 and to the second ends of support r~ils 42 and 44, to further strengthen the support structure 106 and to rein-force bulkhead 34.
As shown in Eigure 6, Diesel engine 28 is mounted on a steel support structure 108 having first and second spaced leg portions 112 and 114, respectively, bolted to opposite sides of engine block 110. The first leg portion 112 is rigidly fixed to the first mounting point via steel mounting pads 66 and 68, and the second leg portion 114 is rigidly fixed to the second mounting point via steel mounting pads 76 and 78. Leg portions 112 and 114 raise engine 28 such that the rotational axis 116 of the engine 35 crankshaft is coaxial with the central axis 41 of opening 40 in bulkhead 34. The flywheel housing 118 of engine 28 is securely bolted to bulkhead 34 by a plurality of bolts ~ 323~ 7 54,234 which utilize bolt openings 120 uniformly spaced about opening 40. Thus, engine 28 is firmly and rigidly mounted to support frame 26 which has a three-point arrangement which utilizes both the horizontal support plane 30 and the vertical support plane 32 to provide exceptional stability.
Engine 28 is rigidly mounted to support frame 26, eliminat-ing costly shock or isol~tion mounts, as well as eliminat-ing pulleys and belts which a shock mounted engine would require for driving elements not rigidly fixed to engine 28.
Engine 28 is liquid cooled, with a crankshaft pulley 122 driving a water pump 124 via a pulley 126 and belt 128. Belt 128 also links a pulley 130 which drives an alternator 132.
Instead of rejecting engine heat from the liquid coolant to ambient via a conventional engine radiator, a liquid-to-air radiator or heat exchanger 134 is utilized to reject heat into the served space 15 defined by the associ-ated trailer 14. Heat exchanger 134, which is preferably of the aluminum fin-copper tube type, is mounted above opening 40 on the second major side 38 of bulkhead 34. The engine water pump 124 is used to provide liquid flow communication between engine 28 and heat exchanger 134 via appropriate hoses 136 and 138 which connect engine 28 with inlet and outlet connectio~ 140 and 142, respectively, on heat exchanger 134. Openings 144 and 146 in bulkhead 34 enable hoses 136 and 138 to communicate with heat exchanger 134.
Air delivery means, preferably in the form of a centrifugal blower 148, is directly and resi~iently mounted to the engine drive means via a flexible coupling 170, e.g., to the engine flywheel drive shaft (not shown), which extends through opening 40 in bulkhead 34, with the blower 148 being below heat exchanger 134. Flexible coupling 170, for example, may comprise a bushing, such as Browning's H
1", and Browning's Ever-Flex Coupling CHCFR5H. In a ~2~3~ 8 54,234 preferred embodiment, blower 148 is preferably a 16.5 inch backward curved blower.
A plenum or heat chamber 150 is formed about blower 148 and heat exchanger 134 which is in the form of metallic box attached to the second major surface 38 of bulkhead 34. Plenum chamber 150 is dimensioned to snugly fit the opening provided in the front wall 12 of trailer 14. A gasket 151 on bulkhead 34 extends about the periph-ery of plenum chamber 150 to seal the trailer opening when cargo heater 10 is attached to trailer wall 12 via a plurality of mounting bolts 153.
Plenum chamber 150 includes a major flat vertical sheet member 152 held in spaced parallel relation from bulkhead 34 via a bottom 154, vertical sides 156 and 158 and a top 160. An opening 162 is provided in sheet member 152 having a central axis which coincides with axis 41; and sized to enable air from the served space 15 to enter blower 148 via its axial inlet. A protective grille (not shown) may be fixed across opening 162 via studs 163 which extend outwardly from sheet member 152.
An air discharge opening 164 is also defined by sheet member 152, sides 156 and 158 and top 160, at the upper end .of plenum chamber 150.
Air rom the served space 15, indicated by arrow 1.66 in Fi~1re 3, is drawn into blower 148, the peripheral air discharged by blower 148 is directed upwardly by plenum chamber 150, through and in heat exchange relation with heat exchanger 134, and the heated air exiting heat ex-changer 1~4 is directed back into the served space 15 by plenum chamber 150 via opening 164, as indicated by arrow 168.
Cargo heater 10 is completed by providing a mounting plate and battery (not shown), on the bottom portion 19 of cover 18, and a bracket and coolant expansion tank (not shown) on bulkhead 34. The bottom 19 of cover 18 may also be used to mount an auxiliary boiler when the heat provided by the churning and compressing of the air by 1323~
9 54,234 blower 148, and by the heat rejected by the liquid engine coolant, do not provide sufficient heating capacity for a particular application. In general, blower agitation by a 3000 CFM blower and engine heat will provide up to 30,000 BTU's per hour, with a boiler extending the capacity up to 100,000 BTU's per hour.
Diesel engine 28 is preferably automatically stopped and started under the control of a thsrmostat in control 16, as disclosed in United States Patent 4,419,866, which is assigned to the same assignee as the present application. This patent is hereby incorporated into the specification of the present application by reference.
In summary, the cargo heater ln of the present invention is specifically constructed for transport sys-tems, such as a trailer of a tractor-trailer unit, and it mounts on the front wall of such a trailer. A structural three-point support frame 26 for a liquid cooled Diesel engine 28 includes a bulkhead 34, a cover 18, and a box-like assembly 106 of structural elements 42, 44, 46, 48 and 50 which interrelate the cover 18 and bulkhead 34 such that all stresses created within cargo heater 10 are transferred from the various support points to larger mass members, and eventually to the front wall 12 of trailer 14, where they are dissipated. Rigidly mounting engine 28 to frame 26 without any type of isolation mounts, and in two intersecting horizontal and vertical planes (right and left hand sides of the engine in a horizontal plane, and the flywheel housing in a vertical plane) spread the load over a wide base which aids stability. Rigidly mounting engine 28 to frame 26 also reduces both maintenance and manufac-turing cost, as it eliminates shock mounts, pulleys and belts, enabling the air delivery means 148 to be directly mounted to the engine output shaft or flywheel.

Claims (8)

1. A transport cargo heater for heating the air of a served space which includes a vertical wall having an outer surface, comprising:
a support frame, said support frame having three support surfaces in vertical and horizontal planes respectively defined by a bulkhead, and first and second spaced engine support rails, said support frame further including front and rear rail members fixed to the first and second engine support rails, said bulkhead having first and second major sides, and an opening having a central axis which extends between said first and second major sides, with the second major side being adapted for mounting on the outer surface of the vertical wall of the served space, means fixing the rear rail member to the first major side of said bulkhead, said engine support rails each having first and second ends and longitudinal axes disposed to intersect the first major side of the bulkhead, an external cover, means rigidly fixing said cover to said bulkhead and to at least the front rail member of the support frame, such that mechanical stresses in the first and second support rails are transferred to the bulkhead via the front rail member and cover, and via the rear rail member, an internal combustion engine having a liquid coolant, means rigidly mounting said engine to said three support surfaces of the support frame, said engine having drive means, including a drive shaft, disposed to enter the opening defined by said bulkhead, air delivery means disposed adjacent to the second major side of the bulkhead, said air delivery means being directly and resiliently fixed to the drive shaft of said engine via a flexible coupling such that said air delivery means is directly driven by the engine drive shaft, a liquid to air heat exchanger disposed adjacent to said air delivery means such that air drawn from a served space by the air delivery means is discharged through said heat exchanger, and means providing liquid flow communication between said heat exchanger and said engine such that engine coolant transfers heat to air passing through the heat exchanger, adding to heat in the air produced by agitation of the air by the air delivery means.

2. The cargo heater of claim 1 wherein the means mounting the engine to the support surfaces rigidly fixes the engine to the first and second engine support rails and to the bulkhead.

3. The cargo heater of claim 1 wherein the air delivery means is resiliently fixed to the engine drive means.

4. The cargo heater of claim 1 including a cover which extends outwardly from the first major side of bulkhead, with the support frame being rigidly fixed to the cover such that mounting stresses in the support frame are transferred from the mounting frame into said cover.

5. The cargo heater of claim 1 wherein the frame includes front and rear support members, with the first ends of the first and second engine support rails being rigidly fixed to said front support member, and with the second ends of the first and second engine support rails being rigidly fixed to the rear support member.

6. The cargo heater of claim 5 including a cover which extends outwardly from the first major side of bulkhead, with the support frame, including the front support member, being rigidly fixed to the cover such that mounting stresses in the support frame are transferred from the mounting frame into said cover.

7. The cargo heater of claim 1 wherein the air delivery means is a centrifugal blower, and including means defining a plenum adjacent to the second major side of the bulkhead, with said plenum having an opening which enables air to be drawn from a served space axially into said blower, said plenum directing air discharged from the blower through the liquid to air heat exchanger, and then out of the plenum and into the served space.

8. The cargo heater of claim 1 wherein the engine has a pump for pumping the liquid coolant through the engine, with said pump also circulating engine coolant through the liquid to air heat exchange.