FR2841640A1 - Livestock feed bale drying procedure uses air flow at higher than ambient temperature that is reversed periodically - Google Patents

Abstract

The procedure for drying feed bales (B) uses an air flow (AC) at above ambient temperature that is forced through the thickness of the bales and is reversed periodically so that it travels through the bales first in one direction and then the other. The temperature of the air flow is between 60 and 130 deg C, and part of the moist air flow (AH) from the bales is recycled and mixed with fresh air (AE) from the outside before the mixture is heated and directed towards the bales. The procedure is carried out in a closed chamber (1) containing the bales between lower (100) and upper (110) mesh surfaces, an air blower (6, 8) and flow reverser (9).

Description

The present invention relates to a method for drying

  fodder, and more particularly fodder conditioned in the form of boots.

  It also relates to a method for implementing this method. By the term "fodder" is meant all vegetable matter

  likely to be part of animal feed.

  By the expression "fodder conditioned in bundles" is meant the fact that the fodder has been compacted to form bundles of variable size and shape, capable of being more easily handled and stored than fodder in

bulk.

  Generally, these boots have a parallelepiped or cylindrical shape. One problem encountered with these boots is that which arises from their conservation when they are stored. It is not uncommon for boots to be made while the forage is still wet. The boots thus produced

  are therefore charged with humidity, which affects their subsequent conservation.

  The same result occurs when the boots, although dry at

  at the time of their compaction, undergo the bad weather before being stored under cover.

  In addition, when a customer must be delivered, we try, as much as possible, to deliver boots of uniform quality. Now, on a set of boots, there

  it is very likely that not all of them contain the same amount of moisture.

  That’s why we created ways to dry boots

for packaging.

  This is particularly the case of the devices described in documents WO-A81 / 0277, WO-A-97/30318 and EP-A-0 361 099. In these three cases, hot air is blown into boots, either through their entire thickness, or from

  the heart of the boots to their periphery.

  In any event, the hot, dry air that enters the boots absorbs some of the moisture it encounters. However, more and more moisture and more and more cold, its capacity to dry the fodder as

  as it progresses in the boots is found diminished.

  Under these conditions, except to continue drying beyond an economically reasonable time, we are dealing with boots whose drying is incomplete, some areas being completely dry, while others are

still wet.

  The object of the present invention is to propose a method and a

  installation which make it possible to remedy this drawback.

  In other words, it aims to provide a simple, economical and easy-to-use process and installation which allows drying in a way

  uniform fodder packaged in the form of bundles.

  The process for drying fodder conditioned in bundles in question is of the type according to which an air flow of temperature greater than ambient temperature is forced through the thickness of said bundles. It is characterized by the fact that the air flow is inverted periodically, so that it

  sometimes cross the boots in one direction, sometimes in the opposite direction.

  In this way, the areas of the boots which are not best dried when traversed by the air flowing in one direction, are

  when they are traversed in the other direction.

  For convenience of language, the expression "air" will be used below.

  warm "to designate air temperature above room temperature.

  According to other characteristics of this process: - the temperature of the air passing through the boots is between 60'C and 130'C; - part of the moisture-laden air leaving said boots is recycled, while being mixed with outside air, this mixture being previously

  warmed up before being directed to the boots.

  The invention also relates to an installation for setting

process work.

  According to preferred characteristics, this installation comprises - a closed enclosure for receiving the boots to be dried, which comprises a first perforated wall forming a support base for the boots, on which they are intended to bear on their underside, and a second perforated wall intended to come into contact with the upper face of said boots; - means for blowing hot air into said boots, so that it enters them by first passing through the first wall, then out via the second wall; means for periodically reversing the direction of insufflation, the air

  entering by the second wall and leaving by the first.

  i -i According to other advantageous but non-limiting characteristics of this installation: - said enclosure comprises a hollow lower box of which at least part of the upper surface is formed of said first perforated wall, a hollow upper box of which at least a part of the lower surface is formed of said second perforated wall, means for adjusting the spacing between said boxes, means for supplying and removing air in and out of the boxes and means for sealing the the peripheral space between the boxes. the air blowing means consist of at least one blowing fan and the installation also comprises at least one fan

  extraction able to extract the air which has passed through the boots, outside the enclosure.

  - Said inversion means consist of a set of registers

  associated with air flow ducts.

  - The means for supplying and evacuating air in and out of the boxes include at least one flexible sleeve connected to the upper box

of the enclosure.

  - It includes means for filtering outside air and air

  evacuated outside the enclosure, prior to recycling.

  the means for adjusting the spacing between said boxes

  consist of a plurality of cylinders.

  Other characteristics of the invention will appear on reading the

  detailed description which follows of a preferred embodiment. This

  description will be made with reference to the accompanying drawings in which:

  - Figures i to 3 are schematic side views of an installation according to the invention, the first two figures showing more particularly the two directions of air circulation in the boots, while the third shows the control equipment in this installation; - Figures 4 to 6 are sectional views, respectively from above, side and end of an air conditioning unit, which is part of the installation. Before describing the implementation of the method according to the invention, we will first describe the installation as shown in the attached figures. It is a possible embodiment, different installations,

  not described here, being capable of allowing the implementation of the method.

  This installation essentially comprises an enclosure 1 of

  reception of boots to dry, as well as an air conditioning unit 2.

  While the equipment constituting this unit is presented very schematically in Figures 1 to 3, Figures 4 to 6 give a more precise idea of the structure of a possible embodiment of the unit

air conditioning.

  The enclosure 1 for receiving the boots to be dried comprises, in the embodiment described here, a first hollow lower box 10 which, seen from

  above, fits in a square, rectangle or circle.

  It is for example made of metal plates and at least one

  part of its upper surface consists of an openwork wall 100.

  The installation also includes a second upper box, referenced 11, of the same type as that previously described, but which has a symmetrically inverted position. This means that at least part of its surface

  lower is also formed of an openwork wall 110.

  The box 10 is fixed, while the box 11 is mobile.

  Adjustment means make it possible to vary the spacing between

these boxes.

  In the example described here, it is a set of double-acting cylinders 12 which make it possible to separate, as desired, the boxes 10 and it relative to each other. The number and arrangement of cylinders are adapted to the size

boxes.

  The enclosure is also equipped with sealing means

  of the peripheral space which is located between the boxes 10 and 11.

  In the example shown, it is a skirt 13 the height of which is intended to be always greater than the maximum spacing between the boxes 10 and 11. This skirt is for example made of a waterproof and deformable material, by example similar to that used for tarpaulins. In addition, it is preferably provided with removable fixing means to the peripheral surface of the boxes 10 and

  11. We will return later in the description on the function and usefulness of this skirt.

  13. As will also be seen below, it is in the space X delimited by the boxes 10 and 11 and the skirt 13, that boots B of forage at

to dry are put in place.

  The enclosure 1 is connected to the unit 2 by two sleeves 20 and 21. The sleeve 20 is preferably provided flexible and deformable, because the box 11

  is likely to move in height.

  As already specified above, FIGS. 1 to 3 give only indications on the equipment of unit 2, while FIGS. 4 to 6 represent a more specific embodiment of it. We will therefore start by referring to Figures 1 to 3, then later and if necessary, to the figures

  4 to 6, for more detailed explanations.

  Starting from the left of Figures 1 to 3, the unit 2 includes a filter 3 for suction of outside air. It communicates with a box 4 for recovering calories and a box 5 for mixing, the function of which will be explained below. To the casing 5 is connected a fan 6 ′ which has the purpose of sucking in the outside air passing through the filter 3 and of directing it towards the enclosure 1. At the outlet of this fan are provided means for heating the air 8 which lead to an air flow reversal box 9, the structure and operation of which will be explained below. This reversing box is connected to enclosure 1 by the sleeves

and 21 cited above.

  The box 9 has an outlet to which a dust recovery filter 7 is connected, itself connected to an exhaust fan 6 which

  communicates with the mixing box 5 which has been mentioned above.

  In the more precise embodiment of FIGS. 4 to 6, the unit is organized into two superimposed stages, namely a low stage in which the blower 6 'is located, and an upper stage in which the

exhaust fan 6.

  These two floors communicate with the same space 26 which

  constitutes both the box 4 for recovering calories.

  Communication between this space 26 and the two lower and upper levels is possible by the installation of partitions in which are embedded registers R7 and Rg, that is to say shutters capable of occupying

  respectively open or closed positions.

  In the upper part of the space 26 is mounted the air suction filter 3 which communicates with the outside with a deflector 260. Similarly, in the lower part, an analog air deflector 261 is provided to allow the exhaust

air outside space 26.

  In addition to the registers R7 and R9 is provided, to communicate the

  two fans, an analog register R8.

  Opposite the space 26, the fan 6 'is connected, via the heating means 8, with a chamber 23 which communicates towards the outside by a register R6. The mouth 22 to which the sleeve 21 described above has been designated by the reference 223. Similarly, the fan 6 communicates, via the recovery filter 7 with an upper chamber 22 which is itself connected to the outside by a register R5. The outlet mouth 220 is connected to the sleeve

20 supra.

  The two upper 22 and lower 23 chambers are connected between

  them by lateral sheaths 24 and 25 also equipped with registers RI to R4.

  Using this set of registers and depending on their respective open and closed position, it is possible to selectively circulate the air only through the lower chamber, only through the chamber

  superior, or from one to the other.

  The installation is used in the following manner.

  After having requested the jacks 12 so as to separate the two boxes 10 and 11 of the enclosure 1 as far as possible from each other, the boots B of fodder to be dried are positioned, for example in the form of a stack of two boots,

  as shown in Figures 1 to 3.

  The jacks are then actuated so that the perforated lower surface 110 of the upper box 11 comes to bear against the upper face of the

boots to dry.

  The skirt 13 is then positioned around the enclosure so as to delimit a closed space X. The two fans 6 and 6 ′ are then started. RI registers

  to R4 are closed, while registers R5 and R6 are open.

  The operation of the supply fan 6 'causes

  the outside air intake AE which passes through the filter 3 as well as the boxes 4 and 5.

  The air thus sampled outside is thus heated, for example to 60 ° C., by means 8. It should be noted that this temperature is however indicative. It is enough that this temperature makes it possible to preserve the digestive and nutritive qualities of the treated fodder. It can go up to 130 ° C if the nature of the forage there

ready.

  The heated air passes through the box 9 via the register R6, passes through the

  chamber 23 and enters the box 10 of the enclosure, via the sleeve 21.

  Because the second fan 6 is also on, there are

  forced circulation of hot air AC through boots B, in the direction of the arrows 1.

  This is made possible by the openwork structure of the surfaces

  upper 100 of box 10 and lower 110 of box 11.

  Always circulating in the same direction 1, the air AH is extracted from the boots. He's wet, and his temperature has dropped. It passes through the sleeve 20 and the

box 9, via register R5.

  It is then rid of the plant fibers which it contains by the filter 7. The air sucked in by the fan 6 is optionally recycled via the boxes 4 and 5. It can also be discharged outside or, more generally, be partially

recycled (AR) and rejected (AX).

  As already said above, the method of the invention essentially consists in periodically alternating the direction of air circulation inside the boots. To do this, we close registers R5 and R6 while we open the

registers RI to R4.

  As a result, the air which leaves the heating means 8 is forced to pass through the upper stage 22 of the box 9, so that it enters the enclosure 1

  by the upper box 11 (arrows m).

  The humid air AH extracted from the boots exits through the lower box 10

  and returns to the boxes 4 and 5, via the filter 7 and the fan 6.

  If you use air above room temperature, it is of course because hot air absorbs more moisture than

cold air.

  In addition, the hot, humid air coming out of the boots has a temperature below the initial heating temperature, but is still likely to be used. This is the reason why the skirt 13 is installed around the enclosure 1 to contain the hot air inside the closed space X, and that a

  heat recovery unit 4 at the outside air intake.

  The mixing box 5 is designed to regulate the proportion of outside air AE and recycled air AR, in order to maintain a maximum profitability ratio (that is to say obtain the best ratio of extracted moisture / consumption

  of heating). This mixture is a function of the position of the registers R7 to Rg.

  Thus, when the registers R7 to Rg are all half open, it is a mixture of outside air AE and recycled air AR which is taken up by the fan 6 '. The hot AC air which passes through the boots and absorbs part of the humidity during its passage is charged with humidity. At the outlet of the boots, the air is more humid and therefore absorbs less

of water for the same volume.

  By periodically reversing the direction of the air through the boots, the absorption of moisture becomes regular in the volume of these, this of course provided that the density of the forage is regular in the volume of the boot. The establishment of an exhaust fan 6 contributes to the fact that the air inside the enclosure 1 is always under vacuum and sticks the skirt 13 against its support. Otherwise, the air inside the enclosure would be overpressure relative to

  outside and the skirt would let the air out of the installation.

  During the drying of the boots, dirt dust (or other) is also dried. They peel off from the forage fibers and are sucked in by the exhaust fan 6. This dust may clog the equipment that the air would have to pass through. This explains the presence of a filter 7, preferably with long pockets. These pockets can be emptied and cleaned with

end of drying.

  The implementation of the method according to the invention can be made of

regulated and automatic way.

  To do this, the installation can be equipped with regulation means

  symbolically represented by the letters a to j in Figure 3.

  Thus, the letter has designated a sensor for measuring the temperature and the humidity of the outside air AE which gives the user a

simple measure of information.

  The device b measures the pressure difference between the inlet and the outlet of the exhaust fan 6. It is, for example, a device from the company KIMO. After a few seconds of checking, the proper functioning of the fans authorizes the operation of the installation. The device is also designed to stop the installation when the measured pressure difference is

  less than a set value.

  The sensor c measures the temperature of the extract air and gives a simple measurement of information. It also measures the humidity of the air

  extraction and controls the opening or closing of the air mixing box 5.

  If it detects that the mixing box 5 has been in 100% air recycling for more than 15 minutes, it is suitable for ending the drying cycle. The d sensor measures the pressure difference between the inlet and the

recovery filter outlet 7.

  It is for example a device from the company KIMO.

  If the pressure measured is lower than a first threshold value, it authorizes the operation of the installation. In the event that the pressure reaches this first threshold value, it activates a contactor which supplies a first

gyroscope and an audible alarm.

  In the event that the pressure reaches a second threshold, it stops the installation completely and activates a contactor which supplies a second

gyroscope and a second alarm.

  The sensor e measures the value of the vacuum of the exhaust fan 6. This measurement makes it possible to manually adjust the speed of said fan.

  The sensor f measures the supply temperature.

  The sensor f also measures the pressure of the supply fan

  6 ', which allows manual adjustment of the speed of said fan.

  The device g measures the pressure difference at the inlet and at the

  supply fan outlet 6 '.

  It authorizes the operation after 30 seconds of control and

the ridge due to lack of pressure.

  The h sensor measures the air temperature after recovery or

  recycling. It is a simple measure of information.

  Finally, the sensor j measures the temperature difference between the supply air and the extract air. If the temperature difference is less than 100

  for more than 15 minutes, this determines the end of drying.

  As regards precisely this end of drying, we usually start by switching off the heating, then we put the box of mixture 5 in

  closed position to receive only 100% outside air.

  We continue in the usual way to cause the periodic inversion

of the air flow direction.

  We then wait 30 minutes for the forage boots to cool.

  And we end up cutting all the motors.

  Of course, all set and regulation values can be modified according to climatic conditions and the quality of drying.

desired by the user.

  Audible and visual alarms and warnings can be

  returned to a room separate from the installation.

  All the indications of temperature, humidity, pressure and time delay can be controlled, modified and saved on a

  computer, for example in a room provided for this purpose.

  The filters used are for example of the brand VENTILFILTRE, while the fans are preferably centrifugal, turbine fans

  jet, sold by the company SOLYVENT-VENTEC.

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Claims (10)

  1. A method of drying fodder conditioned in bundles (B), according to which an air flow (AC) of higher temperature than ambient temperature is forced through the thickness of said bundles (B), characterized in that 'We invert the air flow periodically (AC), so that it sometimes crosses the boots (B) in one direction, sometimes in the opposite direction. 2. Method according to claim 1, characterized in that the   air temperature (AC) passing through the boots is between 60'C and 130'C.   3. Method according to claim 1 or 2, characterized in that part of the moisture-laden air (AH) leaving said boots (B) is recycled, while being mixed with outside air (AE ), this mixture being previously   warmed up before being directed to the boots (B).   4. Installation for implementing the method according to one of the   Claims 1 to 3, characterized in that it comprises:   a closed enclosure (1) for receiving the boots (B) to be dried, which comprises a first perforated wall (100) forming a support base for the boots (B), on which they are intended to bear on their underside, and a second perforated wall (110) intended to come into contact with the upper face of said boots (B); - means for blowing (6 ', 8) hot air (AC) into said boots (B), so that it enters them by first crossing the first wall (100), then comes out via the second wall (110); - means (9) for periodically reversing the direction of insufflation, the air   entering through the second wall (110) and leaving through the first (100).   5. Installation according to claim 4, characterized in that said enclosure (1) comprises: - a hollow lower box (10) of which at least part of the upper surface is formed of said first perforated wall (100); - A hollow upper box (11) at least part of the lower surface of which is formed of said second perforated wall (110); - means for adjusting (12) the spacing between said boxes (10,11);   - Means for supplying and evacuating (20,21) air in and out of the boxes (10,11); - sealing means (13) for the peripheral space located between the boxes (10,11).   6. Installation according to claim 4 or 5, characterized in that the air blowing means (6 ') consist of at least one supply fan and that it also comprises at least one exhaust fan (6 )   able to extract the air (AH) which has passed through the boots (B), outside the enclosure (1).   7. Installation according to one of claims 4 to 6, characterized by   the fact that said reversing means (9) consist of a set of registers (RiR9) associated with air flow ducts (24, 25).   8. Installation according to one of claims 5 to 7, characterized by   the fact that the means for supplying and evacuating air in and out of the boxes comprise at least one flexible sleeve (20) connected to the box upper (i1) of the enclosure (1).   9. Installation according to one of claims 4 to 8, characterized by   the fact that it includes means (3; 7) for filtering the outside air (AE) and   the air (AH) evacuated outside the enclosure (1), prior to its recycling.   10. Installation according to one of claims 5 to 9, characterized by   the fact that the means for adjusting (12) the spacing between said boxes (10,11)   consist of a plurality of cylinders.