CA2099803A1

CA2099803A1 - Batch hay dryer

Info

Publication number: CA2099803A1
Application number: CA 2099803
Authority: CA
Inventors: Fritz Trauttmansdorff
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-07-05
Filing date: 1993-07-05
Publication date: 1995-01-06

Abstract

ABSTRACT

An apparatus for drying forage crops comprises a structure having a floor and an upper support. The floor has a perforated section adapted to receive a plurality of bales of hay from an automatic bale wagon.
A lower plenum mounted under the floor communicates through the perforated section. A heater heats a flow of air. A curtain frame is pivotally connected to the upper support defining an upper plenum communicating with the heater and mounted above the perforated section. There are curtains connected to the curtain frame and curtain drawing devices for opening and closing the curtain frames between a loading position for providing access to the perforated section for loading the plurality of bales of hay thereon and a drying position draping the curtains about the bales of hay closing a path for the flow of air between the heater and the plennum. A fan draws the flow of air through the bales of hay.

Description

` ` 2099803 BATCH HAY DRYER
Field of Invention This invention relates to an apparatus for drying forage crops.
In particular, this invention relates to an apparatus for drying hay.
S Background of Invention Unifl)rmly good quality forage is a necessity for faci]itating anirnal health and productivity. Hay drying assists in this objective by minimizing weather effects on the harvest. Hay drying also improves the effective recovery or yield from the field by virtue of an elevated moisture 3 10 content in the hay matter at harvest.
Hay is normally baled in a convention small square bale. There : have been relatively successful attempts to dry such conven~ional bales.
However, the labor requirement for handling small bales is prohibitively high, whether those bales are wet or dry.
Automatic bale wagons have been used as a means for minimizing the labor requirement of a small square bale harvest. However, innovative methods of joining automatic bale wagon technology to effect hay drying procedures are still required.
Stone, in "Evaluation of Mow Hay Drying System Distribution 20 Systems"; "Energies" publication by the Ontario Ministry of Agriculture and Food, Guelph, Ontario, (1984), demonstrated that in a uniformly plac~d mow of bales, airflow will favor the shortest path from the plenum to the hay surface. Accordingly, efficiency of drying will be greatest when equi-distance air travel pass is imposed.

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-~`` 209~803 i Carson and Kreider, "Forced Feeded Air Drying and Hay";
! Paper No. 88-6583 presented at the 1988 winter meeting of ASAE, Chicago, Illinois, 1988, described the batch drying method commonly used in ~: Pennsylvania for the past 25 years. A typical system would have a two-bay S arrangement, each capable of accommodating eight pallets of 60 to 7U bales.
Heated air is forced through the hay at a rate of 495 L/s*t (100 cfm/ton) at a sl~ temperature of about 28C (50F) above ambient. Drying time using such i method is twenty four to thirty six hours and drying costs is approximately -s $41.60/ton at a yearly production of 625 tons making such method too costly.
Parker, et al. "Development of a Hay Drying System to Use ~'l Automatic Bale Wagons", Paper No. 86-6542 presented at the 1986 winter ;~ meeting of ASAE, Chicago, Illinois, disclosed the use of an automatic bale wagon in conjunction with a batch hay dryer. Pressure balloons were inflated to provide a seal on the exposed faces of the stacks as heated air either by 15 solar or natural gas, was forced upward through the hay. Drying of hay at 30% moisture typically took three to five days to complete. Bales of uniform size and density, in a stable stack were important to the successful operation of this dryer. Hay with dry matter densities ranging from 80 to 160 kg/m3 (5 to 10 lbs/ft3) can be successfully dried and that the addition of 15C of heat 20 may not be enough to prevent some mold formation. One major drawback of Parker, et al. is that overdrying of the bales appeared to be unavoidable.

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~ 2~99803 Summar~ of Invention The disadvantages of the prior art may be overcome by providing a batch hay dryer to be used with an automatic bale wagon.
, According to one aspect of the invention, there is provided an .. S apparatus for drying forage crops. The apparatus has a structure having a ;
floor and an upper support. The floor has a perforated section adapted to receive a plurality of bales of hay from an automatic bale wagon or a similar .~ bale stacking or transporting apparatus. A lower plenum mounted under the ", .
floor communicates through the perforated section. A heater heats a flow of 10 air. A curtain frame is pivotally connected to the upper support defining an upper plenum communicating with the heater and mounted above the perforated section. There are curtains connected to the curtain frame and curtain drawing devices for opening and closing the curtain frames between a loading position for providing access to the perforated section for loading the 15 plurality of bales of hay thereon and a drying position draping the curtains about the bales of hay closing a path for the flow of air between the heater and the plennum. A fan draws the flow of air through the bales of hay sealing the curtains against the bales of hay.
According to another aspect of the invention, the apparatus 20 further includes a side plenum for communicating between the upper plenum ' and the lower plenum, an exhaust vent, and a re-circu]ation baffle for directing , the flow of air between the upper plenum and the exhaust vent.

:, ;, 209~803 According to another aspect of the invention, the apparatus further includes a vent in the upper plenum for introducing atmospheric air into the flow of air.
Description of Drawings S In drawings which illustrate the preferred embodiment of the invention, Figure 1 is a perspective view of the arrangement of bales being unloaded from a bale wagon or a similar bale stacking or transporting apparatus;
Figure 2 is an end view of the hay dryer of the present invention;
Figure 3 is an end view of a plurality of hay dryers of the present invention insta]]ed within a single housing;
and Figure 4 is a side elevational view of the hay dryer of Figures 2 and 3.
Detailed Description of the Invention The invention is generally illustrated in Figures 2, 3 and 4 as 10.
The hay dryer 10 comprises a floor 12 raised above the base footings 14 of the 20 housing 16. Floor 12 is provided with perforated floor section 18 and adapted to extend the length of the hay dryer presenting a surface for receiving the bales 1, 2 and 3. Mounted below floor 12 and communicating through perforated floor section 18 is plenum 22. Mounted within plenum 22 is fan 24 for drawing air therethrough.

- 209'~03 Pivotally mounted on an upper support such as a ceiling are curtain arms 25 and 27. Draped from curtain arms 25 and 27 is a pair of curtains 26 and 28, respectively. Curtains 26 and 28 are preferably '.~i polyethylene sheets. Curtain arms 25 and 27 and curtains 26 and 28 extend from the ceiling 30 to floor 12 along the longitudinal extend of perforated ~; floor section 18. Curtain arms 25 and 27, together with ceiling 30 define an upper plenum 44.
Curtain arms 25 and 27 are provided with curtain drawing means for raising and lowering same between a loading position and drying position.
In the preferred embodiment, wires 29 and 31 connected to the pivoting end of the curtain arm connected to a driven drum 33 and 35 effect the opening ~' and closing of the curtain arms.
Referring to Figure 4, at one end of perforated floor section 18 is a burner unit 32. Burner 32 burns a fuel such as natural gas, propane or 15 the like, and will exhaust heated air upwardly through duct 34 into duct 36.
J Burner 32 has an internal fan for blowing heated air. Duct 36 is provided with a vent 38 which communicates with the atmosphere for introducing fresh air into the system as indicated by the arrow.
~, Burner 32 is mounted at one end of perforated floor section 18 20 providing an abutment wall allowing easy stacking of the bales of hay 1, 2 and 3. The opposite end of perforated floor section 18 is a end curtain frame 37 having end curtain 39 mounted in a similar fashicn as curtain arms 25 and 27.

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When the curtain arms 25, 27 and 37 are lowered into a drying position, the curtains 26, 28 and 39 will seal from floor 12 to ceiling 30 . establishing an airflow pattern as i]lustrated in Figure 4.
At the end of plenum 22 is a side plenum 23 having an exhaust '; ~ vent 40 for exhausting air to the atmosphere as indicated by the arrow.
Plenum 23 is also provided with a recirculation baffle 42 which can be opened and closed to recirculate the heated air back through the system forming a elosed loop.
Ji In use, an automatic bale wagon or a similar bale stacking or 10 transporting apparatus deposits hay bales onto perforated section 18 by tipping the wagon's bed upward and backward. A subsequent stack can be placed against and tight to the face of the first pack as illustrated in Figure 1.
Examples of such automatic bale wagons are available from Sperry New Holland.
Once an arrangement of bales has been deposited, curtains 26, 28 and 39 are dropped from the loading position as illustrated in the right hand side of Figure 3 to its drying position as illustrated in the left hand side of Figure 3 by uncoiling wires 29 and 31.
Once the curtains have been lowered, burner 32 is ignited and 20 fan 24 is turned on causing a flow of air through the hay dryer 10 as indicated in Figure 4. Hot air is exhausted from vent 34 as fresh air is drawn in through vent 38 Into duct 36 to the plenum 44 downwardly through the balet Df hay, -`` 2~99~03 through perforated floor 28 to plenum 22 and outwardly through vent 40. In order to improve the early heating of the air, baffle 42 may initially be closed closing off exhaust vent 40 presenting a substantially closed loop flow of air.
l~eating Requ rements Various calculations were made to estimate the drying potential of air which was increased by 15, 25 and 35C over ambient. Tab]e 1 indicates how temperature rise influences the drying period required for hay at initial moisture contents of 25 and 30 percent moisture (wet basis). Thus, at an airflow rate of 240 L/s*t (S00 cfm/ton) and a 35C temperature rise, hay at 30% moisture can be dried in 20 hours.

Table 1 - Estimated Drying Time (hours) TEMPERATURE INITL~L MOISTURE CONTENT

RISE (C) 25% ¦ 30%

~ 29 _ It is recognized that overdrying of some of the hay will occur.
However, by re-wetting the hay by running only cool ambient air for 2-3 hours after the drying period ends (i.e. after burner 32 is shut off) will produce 20 satisfactory results. Furthermore, if time permits it may be advantageous to " , ' i " . ' : i .

- 2099~03 . turn off the burner when the drying front has travelled 90-95% of the way ;, through the stack. That is, the last hay would be dried using the heat energy .. ~, - .
of the hay above it and by ambient air which has already deposited most of its moisture in the overdried hay in the top portion of the stack.
S In the preferred embodiment, the apparatus has a 9.3 kW (12.5 horsepower) axial fan and a direct fired 220 kW (750,000 BTU) natural gas burner ring on a 2.2 kW (3 horsepower) axial ~an.
Although the disclosure describes and illustrates preferred embodiments of the invention, it is to be understood that the invention is not ,~ .
10 ]imited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art. For a definition of the invention, reference is to be made to the appended claims.

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Claims

1. An apparatus for drying forage crops, comprising:
a structure having a floor and an upper support, a perforated section in said floor, said perforated section adapted to receive a plurality of bales of hay from a bale stacking or transporting apparatus, a lower plenum mounted under the floor for communicating through said perforated section, a heater for heating a flow of air, a curtain frame pivotally connected to said upper support defining an upper plenum communicating with said heater and mounted above said perforated section, curtains connected to said curtain frame, curtain drawing means for opening and closing said curtain frames between a loading position for providing access to said perforated section for loading said plurality of bales of hay thereon and a drying position draping said curtains about said bales of hay closing a path for said flow of air between said heater and said plennum, a fan for drawing said flow of air through said bales of hay.

2. An apparatus as claimed in claim wherein said apparatus further includes a side plenum for communicating between said upper plenum and said lower plenum, said side plenum having an exhaust vent, and a re-circulation baffle for directing said flow of air between said upper plenum and said exhaust vent.

3. An apparatus as claimed in claim 2 wherein said apparatus further includes a vent in the upper plenum for introducing atmospheric air into the flow of air.