CROSS-REFERENCES TO RELATED APPLICATIONS

There are no applications related to this application.

FIELD OF THE INVENTION

In its broader aspect this invention pertains to agricultural building heaters, that is, heaters, frequently called agricultural heaters, designed for use in farm buildings which house poultry, swine, livestock, and, in some instances, grains. More specifically the invention relates to gas fired circulating heaters having burner-fan assemblies widely used, among other buildings, in poultry or brooder houses.

BACKGROUND OF THE INVENTION

Since the most important use of the heaters provided herein will be their installations in poultry houses where chickens and turkeys are grown, that aspect of the invention will be emphasized herein. The aim in poultry growing is to provide conditions that enable chicks to expend energy to increase body weight. Such a goal desirably results in larger, more saleable birds which resist disease. Temperature variations, however, cause chicks to expend energy to sustain their body temperatures rather than to increase their body weights. Such poultry house temperature variations thus lead to smaller, less desirable chickens and turkeys. Temperature variations can also create conditions during which weaker chicks contract diseases that can spread to healthier chicks. Obviously poultry farmers desire to maximize productivity by producing as much meat as possible for the feed consumed. Maintaining proper temperatures, then, is very important in effective poultry growing. It is desirable to keep poultry warm so that the food energy provided produces a gain in weight rather than body heat. To this end, for years the poultry industry has recognized the importance of allowing growing birds to choose their most comfortable areas. In order to provide such microclimates to precisely control them at the growing level, the poultry industry has relied on gas fired heating systems that typically include a plurality of gas burner assemblies in poultry houses. By strategically locating those heating assemblies throughout a poultry house, it is possible to provide an environment which is conducive to the growth of the birds in the flock.

There are two types of heating assemblies currently provided for poultry houses, radiant heaters, and forced air or fan heaters. However only radiant heaters appear to have found their way into the patent art. These radiant gas burner assemblies resemble outdoor yard gas lights, except that they are adapted to be suspended by chains and the like above the flock rather than being mounted on posts like the light fixtures. The most popular radiant heaters are the radiant screen type burners, a few examples being found in such patents as U.S. Pat. Nos. 5,964,214, 5,950,615, 5,328,357, and 4,614,166.

Radiant heaters are not completely satisfactory because they warm the growing birds but not the air. They heat only the side of the body that is within the reflective zone of the heater's parabolic reflector. Humans can rotate their bodies to obtain some measure of comfort using the heat emanating directly from such heaters. But it is unlikely that chickens and turkeys will flip over to balance their heat intake. In addition since a radiant heater's heat and light intensity are directly proportional to the gas input, it is impossible to maintain total darkness when the heaters are in operation. These disadvantages have led to the use of forced air heaters in poultry houses. Since a forced air heater is essentially a very hot flame with a fan behind it pushing large amounts of cold air passed the hot flame there is little room for improvement in such apparatus. This may account for our failure to find them in the patent art. The prior art, then is in the form of brochures published by the companies producing the heaters now on the market, such as the Airstream and Cumberland divisions of GSI of Assumption, Ill., Shenandoah Manufacturing Co., Inc. of Harrisonburg, Va., and Hired-Hand of Bremen, Ala. These heaters have numerous air inlets to admit those large amounts of air. Another popular gas fired heater, the L B White heater, sold by such companies as Gas Works in Yalesville, Conn., and Fort Recovery Equipment Co on line, is also provided with multiple air inlet ports. Fan heaters are generally mounted, not near the ceiling, but a few feet above poultry house floors in order to blow the heat generated by the burner close to the growing birds.

It is difficult to keep the ground warm when heavier colder air settles on it naturally. This has led poultry growers to attempt to lower, even more, their heaters, say to within inches of the floor to supply sufficient air to warm the dirt floors, especially when baby chicks are first introduced into a poultry house. The lowering of the heaters prevents the bedding area from becoming too cold, but it introduces other problems. As will become apparent, agricultural forced air heaters currently marketed for use in poultry houses are not totally satisfactory when used close to the floor.

A problem which is somewhat unique to the poultry industry is that dry feed, feathers and excrement which accumulate on dry poultry house dirt floors produce a remarkably dusty environment. To their disadvantage agricultural forced air heaters on the market are quite susceptible to the accumulation of such dust and other particles. Because of the accumulation of debris the heaters being marketed cannot be used very close to the poultry house floors. Whether the air born contaminants are kicked up by the young birds or emanate from the birds themselves, they can be ingested by the heaters. Contaminated air drawn into commercially available heaters results in accumulations which are detrimental to the burner, the fan motor, and other parts of the heater. Debris settles on horizontal surfaces within the heater, as well as on various other heater surfaces. Since these surfaces must be cleaned, the resulting maintenance of such systems adds significantly to the overall costs of raising the young chickens or turkeys. If the maintenance is deficient debris can gradually diminish the burner flame. The debris also settles on the motor and blower wheel within the heater causing the motor to run at temperatures above its design temperature. Given this environment it can be appreciated that prior art heaters are subject to improvement. It is these improvements which are within the contemplation of this invention.

As will be explained in greater detail hereinafter in conjunction with

FIGS. 1 and 2

of the drawings, in order to admit incoming air the for their blowers and burners the commercial heaters have multiple openings for incoming air in the form of grid-like air intake ports on various heater sides. Other forced air agricultural heaters on the market are provided with similar grids for incoming air, but they are spaced across the heater floor. In the environment described the extensive use of air intake holes is quite disadvantageous. The incorporation of inlet air openings such as those shown in

FIGS. 1 and 2

in the drawings leads to the debris problems alluded to. The inclusion of numerous air inlet openings does provide for greater air flow, and does produce the amount of heat desired. However it is to be realized that the intake holes require compensating adjustments. For instance, the large number of holes render it more difficult to ignite the burner within the time period set by the sensor. A higher gas pressure is required to initiate ignition. Low gas pressures lead to unreliable or failed ignitions due to lean mixtures. After ignition a high gas pressure is also required to compensate for the high air volume that flows through the burner. Since the air-to-fuel mixture required to sustain combustion subjects the heater surfaces to higher temperatures, the outsides of the heaters are hotter to the touch. A higher gas pressure requirement can also be a drawback because some actual field conditions may not be adapted to provide such a high gas pressure demands.

Due to the amount of wet litter and natural perspiration associated with such animals as chickens, turkeys, and pigs, the air within these animal confinements frequently becomes humid. Under these humid conditions it is virtually impossible to prevent the accumulation of debris on the motor and on the blower wheel, as well as around inlet openings and air passageways. Over time the heater's internal air paths become restricted by accumulation, forcing the airstreams to make sharp turns. When this occurs there is a tendency for larger and heavier particles to fall out of the airstream as its velocity drops during changes in direction. If not removed, the deposits build up and become hardened by exposure to damp air. Eventually accumulations tend to form around the inlet openings and on critical surfaces. The buildup often decreases the air volume by obstructing the air passageways. The decrease in air volume, as previously noted, then causes the motor to overheat and run more slowly. In addition, since the heater's gas valve generally is not designed for variable operation, the reduced inflowing air yields a richer fuel which produces a longer, larger, flame which burns hotter and more erratically. This resulting flame increases the combustion chamber temperature, and often activates the heater's high limit switch or harms the inner working parts of the heater. As the debris continues to accumulate the motor will run less and less efficiently. By this invention forced air heaters for poultry houses are improved so that they do not permit accumulations such as those described. The result is that the heater, in effect, is self-cleaning. In addition the flame is not allowed to enter the blower wheel. The improvement herein also permits the poultry house heater herein to be suspended closer to the dirt floor than existing heaters.

Considering now one additional aspect, the eating habits of poultry are highly influenced by daylight hours. To take advantage of this, modern poultry growing techniques embody the practice by growers of simulating the passing of days by periodically darkening their poultry houses to create night-like conditions. The practice has been found to simulate different days. Undertaking this several times a day deceives the birds so that they eat more. This light control practice helps the birds grow faster. As an example, a free-range chicken usually requires up to ten months to attain a five and one-half pound dressed size. When light control techniques are employed chickens reach their five and one half pound dressed size in forty-two to forty-five days rather than the normal ten months. The net affect is that a grower can bring forth eight or nine flocks a year, thus greatly increasing the return on his investment.

Given the foregoing details relative to poultry house heaters it can be seen that militating against the light control practice is the fact that under certain less-than-optimum operating conditions, the higher gas pressure in prior art agricultural heaters causes a portion of the flame to be drawn into the blower wheel. The elongated portion of the flame entering the blower housing results in visible light which is then emitted through the heater's exhaust opening, precluding total room darkness. In addition, the prior art heaters in

FIGS. 1 and 2

do not offer double-wall combustion chamber protection in the case of light and heat since they utilize one or more of the exterior housing panels as part of the combustion chamber. Total darkness is further compromised because combustion light is emitted through the multiple air intake openings that are incorporated in prior art exterior housing panels. The gas fired agricultural heater provided herein does not emit any light at its sides or bottom, thus allowing for total nocturnal or simulated nocturnal darkness conditions in the poultry house. Further, by the improvement herein the poultry house heater, unlike those in the art, does not permit conditions which cause richer fuel flames.

SUMMARY OF THE INVENTION

A widely used type of agricultural heater is improved by this invention. The type of heater improved is a gas fired, forced air or fan heater having combustion, air mixing, blower and blower motor components assembled in a box-like or parallelepiped housing. The improvement herein includes interior heater compartment-forming panels which in combination with roof and floor panels form four distinct chambers within the housing. One of these chambers is a center blower chamber provided with a hot air outlet. On one side of the blower chamber, with a common wall between them, is an adjacent incoming cool air-heated air mixing chamber. On the other side, also separated by a common wall, is an adjacent motor chamber, such that the three chambers are in series. The fourth chamber is a combustion chamber whose location depends upon whether the chamber houses a vertical burner, or horizontal burner, which is new to this art. A blower is supported in the center blower chamber with its axis perpendicular to the common walls. A blower motor is mounted in the motor chamber on the common wall between the motor chamber and the blower chamber with its drive shaft extending into the blower chamber to be coupled to the blower. Air inlets open into the motor chamber, and as the only air inlets in the housing, those air inlets provide all of the air for the heater. Incoming air then initially cools the blower motor. Air passageways are provided to allow air to be drawn from the motor chamber into the air mixing chamber when the blower is operating. An opening in the common wall between the air mixing chamber and the blower chamber allows mixed ambient temperature air and hot air to flow into the blower. Openings leading from the motor chamber to the combustion chamber also allow incoming air to be drawn into the combustion chamber when the blower is operating. A passageway leading from the combustion chamber to the mixing chamber directs hot air from the combustion chamber into the mixing chamber to be mixed with incoming, ambient temperature air, to produce additional heated air to be drawn into the blower. The airflow within the heater thus is unidirectional, flowing, when the blower is operating, from the motor chamber into both the mixing chamber and the combustion chamber, and then into the blower chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

In addition to

FIGS. 1 and 2

, included to illustrate how air is drawn into prior art forced air agricultural heaters, additional drawings are included herein to illustrate the invention, and the best mode presently contemplated for carrying out the invention, as well as additional embodiments thereof.

FIG. 1

is an isometric view illustrating the air inlet ports in one type of gas fired forced air agricultural heater currently on the market.

FIG. 2

is an isometric view illustrating another type of currently marketed agricultural heater with its housing removed to reveal the air inlet ports.

FIG. 3

is an isometric view showing the external appearance of the agricultural heater of this invention as it will be marketed.

FIG. 4

is an isometric view, partially cut away, showing internal portions of one form of the heater of this invention.

FIG. 5

is an isometric view, partially cut away, showing internal portions of the preferred form of the heater of this invention.

FIG. 6

is an enlarged side view illustrating the flame flowing from the horizontal burner depicted in FIG.

5

.

FIG. 7

is an isometric view, similar to

FIG. 3

but showing added outlet deflecting plate and viewing port embodiments.

FIG. 8

is an isometric view, partially cut away to show, in greater detail, an entire deflecting plate assembly.

FIG. 9

is a side view of the heater of the invention showing a vortex created by the deflecting plate assembly of FIG.

8

.

DETAILED DESCRIPTION OF THE INVENTION

The prior art has been discussed quite fully, but for the sake of clarity, prior art

FIGS. 1 and 2

have been included herein.

FIG. 1

is an isometric view which illustrates the general configuration of agricultural heaters of the type usually suspended above floors in poultry and livestock houses. In its as-sold form, designated by the reference numeral

9

, this class of heaters has its components assembled in a framework within a box-like or parallelepiped housing

20

preferably fabricated of metal.

Shown in

FIG. 1

are side panels

11

(one being not visible), front panel

13

and a rear oppositely disposed panel, also not visible, along with top panel

15

and bottom panel

16

that form the parallelepiped housing

20

.

FIG. 1

is a view of forced air heaters widely sold by a well-known manufacturer. The extensive use of inlet air openings can be seen in the figure. This type of heater is provided with rectangular ports

17

in at least two of its panels, such as side panel

11

, its oppositely disposed side panel, not shown, front panel

13

, and its back panel, which also is not visible. As shown in

FIG. 1

, in this commercially available agricultural heater, even bottom panel

16

of housing

20

is provided with a number of air inlet openings or ports.

FIG. 2

is an isometric view of a highly commercial agricultural heater. These heaters carry their air intake openings

19

in the bottom or floor panel

21

. The housing encasing the heater components has not been shown so that these ports can be seen. Ports

19

extend in rows all the way across the floor panel as shown and are so close together they resemble a grid-work. With the housing removed burner

22

, flame deflecting baffles

23

and blower

24

, with its inlet

25

, are visible. Because of the huge number of air intake ports there is no separate mixing zone. The grid-work in the floor beneath the burner

22

is provided for heated air-cooled air mixing. The floor of motor area

26

is also provided with air intake ports

19

. From this view of the grid-work it can be seen that the poultry house dusty environment is a matter of concern.

Referring now to

FIG. 3

, shown in that figure is one embodiment of the forced air heater of this invention. It can be seen that the heater

10

is in the form of a parallelepiped structure formed by housing

20

. The rectangular front panel

30

a

, a back panel (not shown), a rectangular side panel

31

, the other side panel (not shown) and the top panel

32

are illustrated in

FIG. 3

, with the bottom panel not being visible. Front opening

33

is the hot air outlet, a modified form of which is to be discussed hereinafter. Also shown in the housing of heater

10

of the invention are rows

34

of inlet air ports in the side panel

31

, which encloses the blower motor chamber. It is again emphasized that this series of openings

34

is the only air intake opening to the heater. It follows that the incoming air must flow from the motor area into all of the other functional areas. To achieve this flow the functional areas have been divided into chambers. This array of chambers will become clear by referring to FIG.

4

.

FIG. 4

is an isometric view, partially cutaway, to show the internal portions of the heater of this invention. By the use of vertical panels

36

and

37

the heater herein has been divided into three separate chambers. Panels

36

and

37

are disposed as common walls parallel to the side panels, such as side panel

31

, to form these three chambers. Between panels or common walls

36

and

37

blower

39

is mounted in blower chamber

40

. It should be stressed at this juncture that the ignition system, the controls, the burner, the other heater components, and the blower are not the essence of this invention. Rather, they are those used in the prior art heaters mentioned hereinbefore. Thus the blower is a standard squirrel cage blower or fan chamber capable of delivering hot air at a rate of 520 to 2,000 CFM. Panel

36

serves as a common wall between blower chamber

40

and mixing chamber

42

. In mixing chamber

42

incoming cool air, that is, ambient temperature air, mixes with hot air generated by the burner

50

in combustion chamber

52

. The inner wall of mixing chamber

42

is the other side of common wall

36

between the mixing chamber and the blower chamber. The other common wall

37

is placed between blower chamber

40

and the motor chamber (

44

). Motor chamber

44

is fabricated to form an enclosure so that incoming air, before traveling through passageways to the mixing chamber, and through ports to the combustion chamber, first cools the motor. Motor

46

is mounted on a motor plate

47

so that the entire motor and plate assembly can be mounted/removed from common wall

37

as a unit. Motor

46

, then, is mounted on the motor chamber side of common wall

37

with the drive shaft of motor

46

extending through common wall

37

in alignment with the axis of blower

39

. The motor drive shaft is coupled to the blower so that blower

39

is driven by the motor, say, a standard one-eighth, one-fourth or one-third horsepower electric motor.

Vertical burner

50

is housed in a separate combustion chamber

52

which is formed by sidewalls

53

and

54

and a back wall

59

behind burner

50

. Burner

50

can be a readily available gas-fired (LP or natural gas) direct spark or hot surface ignited burner having an output of 5,000 to 250,000 BTUH. Combustion chamber sidewalls

53

and

54

are provided with air intake ports

56

for the passage of air from the motor chamber

44

where it is first drawn in through ports

34

of FIG.

3

. Combustion chamber

52

includes the area enclosed by chamber walls

53

and

54

, burner

50

, and baffle

57

, beneath which the flame is ignited. The baffle diverts the burner flame from a vertical flame to a horizontal flame. Air openings

56

supply the air from motor chamber

44

for ignition. The ignited burner flame is deflected by arcuate baffle

57

into channel

61

and is then drawn around baffle

63

by blower

39

into mixing chamber

42

as will be explained further in conjunction with FIG.

6

. In

FIG. 4

heater top

32

has been cut away to show baffle

57

which confines and diverts hot air emanating from the burner so that it can be directed through channel

61

to the mixing chamber (

42

). Channel

61

is formed by inner combustion chamber sidewalls

65

(only one being visible), a channel bottom

64

and a channel top

66

. It has been found that the long flame path provides additional burn time, leading to greater combustion efficiency and low carbon monoxide emission. One of the features of this embodiment is the provision of a long flame. To this end channel

61

is part of combustion chamber

52

as it extends across the tops of the three chambers

44

,

40

, and

42

. Because of the long flame path, additional air, flowing from motor chamber

44

, is supplied to the flame through openings

58

a

and

58

b

. This ensures complete combustion and provides a gas force partially lifting the flame above panel

64

. The air entering combustion chamber

52

must be slowed down and reduced in volume so that dilution of the fuel mixture within burner

50

chamber is minimized. This downstream metering of air by ports

58

a

and

58

b

ensures that a rich fuel and air mixture is available for ignition, even when supplied gas pressure is lower than normally recommended.

Another improvement in this embodiment stems from the location of the heater air inlet openings (

34

in

FIGS. 3

) relative to the air inlet openings (

56

in

FIG. 4

) leading to the combustion chamber. As can be seen these openings are positioned at an angle to each other, and in close proximity. Inlet openings

34

are situated beside combustion chamber openings

56

. Fast moving airstreams within an enclosed structure cannot make abrupt ninety degrees turns without slowing down or undergoing deceleration forces. To take advantage of this fact, air intake ports

56

(

FIG. 4

) are positioned at a 90□ angle relative to the main airstream entering the heater through openings

34

. With this arrangement most of the incoming air does not make the ninety degrees transition through inlet ports

56

. Rather, the larger quantity of incoming air drawn by the blower bypasses combustion intake ports

56

and moves on to inlet ports

55

a

,

58

a

,

58

b

, and

58

c

. (See FIG.

4

). Most of the incoming air, thus, flows naturally upwardly around burner

50

toward baffle

57

, with only a portion being drawn into the burner to mix with the supplied fuel vapor. Because of the small surface area of air inlet ports

34

relative to the heater's exhaust flow rate, a high airflow rate or velocity is achieved by this invention. For instance, with an exhaust rate of 800 to 1100 cubic feet per minute the average inlet air velocity through ports

34

in

FIG. 3

will be increased to about 3200 to 4200 feet per minute due to the smaller surface area of inlet ports

34

. An inlet air velocity of this caliber can lead to burner control problems. However herein, instead of injecting a high velocity air inlet stream directly into combustion chamber

52

a portion of the turbulent high velocity airstream is siphoned off by the arrangement of the two air inlets

34

and

56

. The stream introduced into the combustion chamber through inlets

56

is a low pressure, slower moving, lower volume airstream in order to provide a desirable fuel mixture for ignition.

As implied in the preceding discussion of the increase in air velocity within the heater herein, one of the goals of the design of the heater is to create highly energized turbulent flow within it. A high velocity flow is important for both cooling and air metering functions. The generation and regulation of a turbulent airflow within the heater's interior plays an important role in keeping the exterior panels cool to the touch. Turbulent fluid flow is, thus, a desired flow characteristic. It is more effective than laminar flow at removing heat because it tends to break up the thin boundary layer that exists between a moving fluid and a surface. Its control not only promotes cooling, but that control also allows for an air metering capability inside combustion chamber

52

. For this reason, inlet ports

34

(

FIG. 3

) are divided into smaller ports. Similarly, inlet ports

56

(

FIG. 4

) are divided into even smaller openings, preferably about one-half the size of ports

34

. Since the path taken by the airstream from combustion

52

, through channel

61

, and finally to mixing chamber

42

, is longer and more restrictive than the side and bottom channels of the heater, it is natural that the vacuum created in the combustion chamber by blower

39

is lower.

As indicated hereinbefore still another feature of this invention is the provision of a heater whose housing surfaces are not hot to the touch. In addition to the velocity aspect discussed, to accomplish this various air spaces or air gaps and built-in heat sinks (to be described) are included in the heater design. There is, for example, an air space

55

a

between panel

55

c

and the housing front wall

30

a

. A similar air space is fabricated along the back of the heater. Another air space is provided between housing top

32

and the tops

66

and

67

of combustion channel

61

. In general these air gaps function as built in heat shields or heat barriers between the hot inner surfaces within the heater, and the exterior housing surfaces. The air gaps are sized for the amount of air that will be passing through them at the designed air throughput speed. As a guide, the air gap must not be so small that it generates a backpressure when the system is operating.

In addition to the cooling achieved by the air spaces, strips or dividers can be fabricated between various adjacent openings within the heater to function as heat sinks. An example is divider

90

in

FIG. 4

between openings

58

c

which will lower the temperature of panel

37

. Not shown are similar cooling webs or strips on panel

36

. Though not shown, webs

90

in the preferred embodiment may be rotated in any included angle normal to the direction of airflow from plus 90-degree to minus 90-degree. In addition, by alternating the angle from one web to the next such that any two consecutive webs are at some included angle other than zero or 180 degrees, both heat transfer and turbulence generation are greatly enhanced.

The incorporation of an airstream temperature barrier can be better exemplified by a, discussion of the airflow through heater

10

of the invention. As explained in conjunction with

FIG. 3

all of the air for the heater

10

enters motor chamber

44

through ports

34

. When the blower is operating the incoming airflow divides so as to circulate in several airstreams flowing through various passageways toward the mixing chamber as will now be described in conjunction with FIG.

4

. Since all of the incoming air drawn in through air intake ports

34

will be drawn toward the blower, it flows first into the mixing chamber (

42

). One airstream passes through openings

56

into the combustion chamber

52

as described hereinbefore in conjunction with ports

58

a

and

58

b

. This stream then splits into two components. One component flows into burner

50

, and then into combustion channel

61

. Channel

61

directs the heated gas stream into mixing chamber

42

. The other component flows in a passageway

45

which is formed between the top side of combustion chamber roof

66

, as well as

67

, and the underside of heater top panel

32

. After cooling the inside surface of housing top panel

32

the airstream component flows across the combustion chamber roof

66

and

67

, and finally into mixing chamber

42

through ports

60

a

. Another airstream carries a greater quantity of air from the motor chamber through openings

58

c

. This stream flows beneath blower chamber

40

and behind inner panel

55

c

into the mixing chamber. The front and back passageways can be visualized by referring to

55

c

in FIG.

4

. The incoming airstream flows into this passageway

55

a

between an inner panel wall

55

c

and housing front panel wall

30

a

on its way to mixing chamber

42

. To adequately cool the front panel wall

30

a

of the heater airflow passageway

55

a

extends upwardly as far as top panel

67

(FIG.

4

). After cooling the front heater housing wall, the air flows into mixing chamber

42

through ports

60

and

60

a

. A similar arrangement (not shown) exists along the back side of heater

10

. The cooling of the heater floor is accomplished by the air entering the motor chamber

44

which then flows through ports

58

c

along the floor until it enters the mixing chamber. It is to be understood that the use of similar inner cooling passageways also prevents the side walls of the housing from becoming overly hot. It can now be seen that flow of air through the heater herein is indeed virtually unidirectional. It can also be seen that cooling streams flow in passageways or channels formed along the inside walls of all six sides of the parallelepiped housing of this invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

In its preferred form the heater of this invention includes a horizontal burner. A horizontally disposed burner, new to this art, permits a longer than conventional flame path to be employed while also allowing for a controllable, compact, heating unit. By controllable we mean that with a horizontal burner the flame path can be so adjusted that it can be set to end just short of the blower entrance. Flame entering a blower is not only detrimental to the blower impeller, by unduly heating the blades, but the resulting flame is a source of light. In prior art heaters the numerous air intake openings are not fabricated to dispel light when darkness is desired in order to simulate the end of a day. By the same token light emanating because the tip of a flame entered a blower has not been dealt with.

For a better understanding of a horizontal burner heater

FIG. 5

is given. Referring to that figure it can be seen that combustion chamber

72

lays across the tops or roofs of motor chamber

44

, blower chamber

40

, and mixing chamber

42

. Air intake openings or ports

71

a

and

71

b

provide air for ignition and combustion as did ports

56

,

58

a

and

58

b

in the heater shown in FIG.

4

. Burner

70

is supported in its horizontal position by brackets

73

and

75

which support the burner above the combustion chamber floor so that it can receive air from below through ports

71

a

and

71

b

. Also shown in

FIG. 5

are an electronically actuated gas valve

76

, an igniter

77

, a gas pipe

78

, a high temperature limit or automatic shut-off switch

80

, and gas orifice unit

82

. A flame probe

84

detects the presence of a flame. All of these components, for example, the electronically actuated gas valve

76

, gas pipe

78

, and the other heater parts shown are well known and, being readily available, are incorporated in the majority of the agricultural heaters of this type.

As can be visualized by viewing

FIG. 5

the flame actually emanates beneath bracket

73

just above the common wall

36

between the blower chamber

40

and the mixing chamber

42

. This means that there is no flame above motor chamber

44

, and blower chamber

40

. Their housing walls, then, need not be heat protected. Hence the housing front and rear walls

30

a

and

30

b

can serve as the walls of those chambers. Accordingly front heat barrier wall

55

c

and the corresponding back barrier wall terminate at the blower chamber common wall

36

. Downstream from the blower flame the front and rear housing walls

30

a

and

30

b

are heat protected by inner heat barrier walls

55

c

and airflow passageway

55

a

as explained in conjunction with FIG.

4

. The housing top panel

32

of the heater above the flame area is heat protected by heat shield or heat barrier panel

67

which is installed in the area above combustion chamber

72

.

On further considering

FIG. 5

it is to be realized that the motor, blower, and mixing chambers beneath combustion chamber

72

are structurally and functionally similar to those in the heater previously described in connection with FIG.

4

. To repeat, then, all of the air for heater

10

first enters the motor chamber

44

through a single entry panel, that is, ports

34

in panel

31

. In this embodiment also, the airstream divides to flow as several streams passing through various passageways, all in the direction of mixing chamber

42

. As in the embodiment with the vertically disposed burner the airstream passes into the combustion chamber

72

, this time through openings

71

a

and

71

b

which are similar in location to ports

58

a

and

58

b

in FIG.

4

. Thus the arrangement and sizing of openings

71

a

and

71

b

serve the same basic functions as ports

58

a

and

58

b

in FIG.

4

. They are designed to provide the same means for low gas pressure operation by slowing down the stream of air and reducing its volume. Concomitantly flame from burner

70

is drawn around the top of baffle

63

by blower

39

during operation. In prior art heating units the flame is deflected into the mixing area by a baffle. Rather, herein the flame travels horizontally and then makes almost a 180 degree downward turn across baffle

63

as it enters the mixing chamber. Slot

74

in baffle

63

is merely an expansion joint. In order to increase the quantity of hot air entering mixing chamber

42

, another airstream carrying a greater quantity of air flows from the motor chamber

44

, through openings

58

c

in the base of common wall

37

. This airstream flows beneath blower

39

, and, passes through openings, not visible, but similar to

58

c

in common wall

36

as it enters mixing chamber

42

.

An additional feature herein is the provision of means for heat protecting the barrier walls themselves (See walls

55

c

, FIG.

5

). To cool these front and back interior walls

55

c

, while further protecting front and rear housing walls

30

a

and

30

b

, additional passageways or channels are incorporated in the heater to direct airstreams on both sides of walls

55

c

. Returning to

FIG. 5

it can be seen that in addition to passageway

55

a

directing air across the front of interior wall

55

c

as in the embodiment in

FIG. 4

, an additional passageway or channel

55

b

is included in this preferred embodiment. As can be seen the added passageway

55

b

emanates just below blower

39

, and it directs a flow of air along the backside of inner wall

55

c

to protect the metal from which that inner wall is fabricated. The passageway formed behind barrier panel

55

c

thus allows air to protect both sides of that panel, and then to flow upwardly as far as top panel

67

before passing into the mixing chamber

42

through ports

60

and

60

a

. As in the vertically disposed embodiment, panels

36

and

37

also have cooling heat sink strips

90

formed between adjacent openings

58

c.

An especially unique feature of the preferred agricultural house heater of this invention is its inclusion of not only a horizontal flame path, but a horizontal burner. Prior art heaters produce horizontal flames from burners having gas ports directed vertically with the resulting flame deflected ninety degrees into a horizontal flow. Such diverted flames are sensitive to disruptive flows of air. The horizontal burner of this invention, although illustrated in

FIG. 5

, is shown in greater detail in

FIG. 6

, which is a partially cut away side view of the portion of the heater, showing the horizontally disposed burner

70

as it is supported by bracket

73

. Burner

70

lies across the top of panel

64

so that its flame is drawn across the top of arcuate panel

63

, disposed in mixing chamber

42

adjacent blower chamber

40

. It is to be pointed out that even after vertical flames in existing heaters are directed into horizontal flow, the flame is guided by a baffle above the flame to divert it downwardly into an ambient air-hot air mixing area. In other words the flame flows along the underside of a baffle, whereas, during operation, the flame herein is drawn across the top surface of the panel or baffle

63

as shown at

115

a

in FIG.

6

. The distance of the burner element above the combustion floor panel, and the length of the baffle plate arc are such that the burner flame terminates at the end of the baffle rather than in the blower.

Referring now in greater detail to the disruptive flow aspect, the diversion of a flame, say from the vertical to the horizontal, can lead to an erratic flame. Bracket

73

(

FIG. 6

) serves not only as a mounting platform for igniter

77

, but for a high-limit switch

80

which causes the gas valve to close when the flame becomes erratic. Whether the flame is disrupted by a gust of air, or whether the disruption is caused by some restriction, it will loose its normal disposition, such as

115

a

, and assume some erratic disposition, such as

115

b

, shown by the phantom lines in FIG.

6

. Some outside heaters employ various additional baffles, and even adjustable shutters, to ensure that unwanted gusts of wind do not disrupt their flames. Such precautionary measures are necessary to prevent an erratic flame from tripping the high-limit switch or the flame probe. Since the flame emanating from the burner illustrated in

FIG. 6

is not diverted from a vertical to a horizontal disposition, but is ejected horizontally it is more stable. It is, therefore, less subject to disruption, and readily drawn across the top surface of arcuate panel

63

.

Most prior art heaters have a high-limit switch mounted facing the flame some distance away from the burner's opening. However, as the flame travels away from a burner's opening, it is transformed from a coherent flame into an incoherent flame that resembles ends of paper streamers fluttering in the wind as can be seen by observing flame

115

a

in FIG.

6

. Since their high-limit switch is often mounted only a few inches away from the incoherent portion of the flame, the flame can activate the high-limit switch initiating an overheating alarm which is false. As seen in

FIG. 6

, igniter

80

herein is strategically mounted very close to the origin of the flame

115

a

, and perpendicular thereto. There are two reasons for this. One, by mounting high-limit switch

80

close to the opening of burner

70

where the flame is more coherent, the switch is less likely to be affected by the incoherent end of the flame. Second, since the high-limit switch is mounted perpendicular to flame it receives a smaller amount of heat from the flame by convection and radiation, and therefore runs cooler. On the other hand, when a disruption causes flame

115

a

to rise upwardly as illustrated by phantom lines

115

b

, it will contact the sensing surface

116

of high-limit switch

80

and bring the sensor to its activation temperature in less than a second, safely shutting of the gas valve before internal components are subjected to destructive overheating.

Also unique to the agricultural heater of this invention is the disposition of the deflection plate or awning

92

illustrated in FIG.

7

. For this embodiment we refer now to

FIGS. 7

,

8

, and

9

. Through testing and test results it was discovered that unexpected advantages were obtained by the use of a heater outlet deflection plate, the entire assembly

91

of which is shown in

FIG. 8

as an enlarged portion of the heater outlet partially cut away. As can be seen in

FIG. 8

deflection plate

92

is attached along the top edge of hot air outlet

33

in front panel

30

a

. Supported in hot air outlet

33

, the angular deflection plate

92

formed from a single piece of sheet metal or fabricated as a short awning made of plastic. When the inclusion of a deflection plate was planned it was intended merely to deflect the outlet hot air downwardly to compensate for the elevation of the heater. However, instead of merely deflecting the hot air downwardly, to then rise because of its lighter weight and loss of forward momentum, it was found that when the deflection panel

92

herein was curved downwardly to form an angle of about 30 degrees with the horizontal it generated a flow resembling a horizontal vortex, diagrammatically illustrated in FIG.

9

. The vortex

96

emanated at the tip just below deflection plate

92

and rotated along the floor

97

as seen in FIG.

9

. It was also found that the vortex enhanced the mixing of hot air flowing out of the heater with ambient air in the poultry house. Having made this discovery, we devised a series of tests to better quantify the flow pattern and relative strength of these horizontal vortices. By placing streamers or paper strips and small 1″×1″×4″ rectangular foam blocks on their ends at two feet increments along the floor, we were able to observe the flow pattern and force of the vortex. With the heater suspended at a height of 28 inches from the floor, the mixed hot air-ambient air vortex knocked over rectangular blocks placed as close as six feet from the heater outlet, and those as far away as 28 feet as it rolled along the floor. It then remained to observe how the horizontal vortex enhanced the mixing of hot and cold air at the ground level. In order to create a colder and denser air ground level atmosphere similar to that in a poultry house on a typical winter day, a three-inch thick fog blanket was created using dry ice and water. To prevent ambient air from skewing the results, cold air was introduced into the test area for fifteen seconds prior to the test. Within seconds, the heated air from heater outlet

33

began rotating in a cyclonic manner, quickly dispelling the fog blanket and knocking over all of the foam blocks within sixteen feet of the heater. Fifteen seconds or so later the rotating airstream or vortex knocked over foam blocks positioned as far away as the twenty-eight foot marker. Even though the force of the vortex had decreased so that it did not knock over the remaining foam blocks, it continued to disperse the fog and dust particles on the floor for at least six additional feet. In the same tests, using commercially available heaters, the hot airstream leaving the heater quickly rose from its twenty-eight inch baseline to approximately six feet by the time it reached the twelve-foot mark. It did not knock over a single foam block or cause any of the paper streamers to flutter. These observations and test results showed that the rotational momentum induced by the deflection plate prevented the hot airstream from rising naturally toward the ceiling.

Having been given the teachings of this invention modifications will occur to those skilled in the art. Thus, instead of being fabricated so that it is integral with the front heated wall, deflection plate

91

can be made as an assembly with a portion extending into, or forming a part of air outlet

33

as illustrated in FIG.

8

. The assembly can also be adapted to be secured to the blower housing roof. The top of blower housing

39

and the inner portion of the deflection plate can be provided with a series of mounting holes

95

(two being visible) arranged to allow for front-to-back adjustments. Slots

94

on blower housing top

39

can also be included to provide fine adjustments for deflection plate assembly

91

. While deflection plate assembly can be clearly visible when in its fully extended position as in

FIG. 8

, it can be retracted and hidden from view. As another variation a peephole with or without a glass or clear plastic window, such as

64

in

FIG. 7

, can be installed for observing the flame and the mode of operation of the heater as well as for other purposes. As still another modification, in lieu of two rows of incoming air inlet ports

34

as illustrated in

FIG. 3

, any arrangement of incoming air inlet ports can be employed, one example being the rows of inlet ports

34

also shown in FIG.

7

. In addition none of the air ports need be configured as shown, but can be circular, triangular, or in any other desired shape. Likewise the vertical burner need not be adjacent the motor chamber, but can be placed in any of several other locations. Other such ramifications which will be obvious to those skilled in the art are deemed to be within the scope of this invention.