WO1994012013A1 - Process and device for drying green fodder - Google Patents

Abstract

In a process for drying agricultural green fodder, it is to be pre-aerated by means of a blower (5) after it has been stored under cover (2). This is followed by initial blowing and the temperature of the green fodder in the store (1) is measured by means of a temperature probe (9). In addition, a further temperature probe (13) is used to measure the temperature of the air blow in by the blower (5). Via a switching circuit (26), a control circuit finds the difference between the two temperatures and controls the operation of the blower (5) in accordance with this difference and the humidity measured by a humidity probe (15). This ensures careful drying of the fodder and the retention of its nutrients.

Description

 Method and device for drying green fodder

The invention relates to a method for drying green fodder for animals, such as grasses, clover, oilseed rape, etc., air being blown into the green fodder stored under the roof after its introduction by means of a blower for a predetermined time, in particular several hours, as pre-aeration and then the temperature of the green fodder and the humidity of the air sucked in by the fan are measured and compared with predetermined / certain limit values in an electrical circuit for controlling the fan operation. Furthermore, the invention relates to a device for performing such a method.

A method of the type described is known from AT-PS 394 268. It has the advantage that the valuable nutrients contained in the green fodder, for example proteins and protein, are retained and that the controlled ventilation of the green fodder avoids degradation losses which can occur due to bacterial activity at elevated temperatures. The object of the invention is to further improve such a method, in particular with regard to the adaptation to different weather conditions in the environment in which the storage containing the green fodder is located. The invention is based on the knowledge that it is not only the temperature in the green fodder itself that is important for the preservation of the valuable components of the green fodder, but also the temperature of the air blown into the green fodder and further consideration of the air humidity . Proceeding from this, the method according to the invention consists in that an initial ventilation depending on the humidity of the air drawn in by the blower is carried out and that after the initial ventilation the temperature of the air supplied to the green fodder is also measured and that the air is also blown into the green fodder depending on the difference in the temperature of the green fodder and the air blown into it is controlled in such a way that the blowing in of air is interrupted as soon as the temperature difference mentioned within a predetermined interval, for example 3 ° C., for a predetermined time, for example 1 , 5 hours remains. Compliance with the temperature interval mentioned for a long time indicates that the green fodder has already reached a sufficient degree of drying, so that temporarily no further ventilation is necessary. Only when the If the temperature in the green fodder rises again, which is an indication of secondary fermentation in the green fodder, the aforementioned temperature interval is left, which triggers renewed ventilation via the control circuit. This also avoids over-ventilation of the green fodder and saves energy for blower operation.

According to a development of the method according to the invention, the air is blown in at intervals, for example every 2.5 hours for 15 minutes. This also saves energy. Damage to the green fodder through low temperature is in the context of the invention, avoided by the injection of air is interrupted in the green fodder, when the temperature of Grüπfutters falls below a predetermined value, for example 24 ° C _j.

As already mentioned, however, the monitoring of the air humidity also has an influence on the implementation of the method according to the invention. According to a preferred embodiment of the method according to the invention, the procedure is such that when a predetermined limit value of the air humidity (e.g. 65% for green fodder) is exceeded, the initial ventilation is only carried out if the temperature of the green fodder exceeds the predetermined temperature value. If the air humidity exceeds the predetermined limit value, effective drying of the green fodder is no longer possible since the air to be blown into the green fodder is too moist. It must then be waited for the air humidity in the area around the green fodder store to drop, but the temperature in the green fodder must not become too high. If this temperature exceeds the predetermined limit value, the green fodder must be ventilated in order to remove the heat from the green fodder, without the green fodder drying, however.

On the other hand, according to a preferred embodiment of the method according to the invention, the procedure is such that when the air humidity falls below a predetermined limit (for example 65%), the initial ventilation is carried out, preferably at intervals, until the temperature difference mentioned remains within the predetermined temperature interval and or or the air humidity rises again above the predetermined limit.

The values mentioned for the temperature of the green fodder for interval ventilation and for the air humidity apply to common types of green fodder; in special cases, other values can be selected. For the controlled aeration of grain (grain), it has already been proposed (WO 87/05685) to first determine the desired moisture content of a certain stored grain type. The temperature and humidity of the environment are then measured and a moisture equilibrium and an average temperature are calculated from this. Then the moisture balance is compared with the desired moisture content of the stored grain and the current temperature with the average temperature. The grain is ventilated when the ambient humidity is within a predetermined range of the desired grain moisture and the present air temperature is within a predetermined range of the average ambient temperature and, moreover, ventilation time is still available since a daily ventilation time is not exceeded shall be. This method is complicated and is based on different requirements than the method according to the invention.

The device according to the invention for carrying out the method according to the invention is based on a system with a storage for the green fodder provided with a roof, a blower for ventilation, the same, a temperature sensor for measuring the temperature of the green fodder and a moisture sensor for measuring the air humidity of the air drawn in by the blower and with an electrical control circuit which switches the blower on or off depending on the measured temperature and air humidity values. Proceeding from this, the device according to the invention is characterized in that there is at least one further temperature sensor for measuring the temperature of the air blown in by the fan and in that the control circuit has a circuit for forming a difference value between this temperature and the temperature of the green fodder. Such a relatively simple system is sufficient to successfully carry out the method according to the invention. According to a development of the invention, however, a temperature sensor is preferably also provided for measuring the temperature of the air to be sucked in by the blower, so that the blower does not have to be used unnecessarily at a high outside temperature, particularly in the evening. The invention makes it possible to provide more than one store for the green fodder, each store having at least one temperature sensor for the green fodder in it and this store to a distribution device for the air conveyed by the blower connected to the pressure port of the common blower are connected. A single blower is therefore sufficient for two or more stores, since the stores are generally only supplied with air from the blower at intervals. With suitable programming of the electrical control circuit for the blower operation, it is easily possible to ensure an adequate supply of all the stores with air conveyed by the common blower. In the frame, the distribution device preferably has a flap which is pivotably mounted in a distribution housing and is actuated by a drive, for example a servomotor, which is fed accordingly by the control circuit. Further characteristics and advantages of the invention result from the

Description of an embodiment which is shown schematically in the drawing. Fig.l shows the principle of the system, Fig.2 shows a system with two feeding sticks in plan view, partially cut away and Fig.3 shows in detail the attachment of the blower to a system with two stores.

According to Fig.l, a storage 1 formed by a container is provided for the accommodation of harvested green fodder, which is designed as a conventional fodder stick and is covered by a roof 2. At a distance from its bottom 3, the store 1 has a grate 4 on which the green fodder, not shown, rests. Below this grate 4, the pressure port of a blower 5 opens, so that the green fodder can be ventilated from below through the grate 4. The fan 5 is switched on or off by an electronic control circuit 6 via a line 7. This line 7 is advantageously designed as a special cable with a rubber jacket and designed for extremely heavy loads, so that the line 7 can be run over by a vehicle without damage. This line 7 is expediently also conspicuously designed with a signal color (for example orange). A star-delta automatic start-up 8 is also switched on in line 7. The motor of the blower 5 is controlled by the control circuit 6 as a function of the temperature of the fodder in the store 1, further as a function of the temperature of the air blown into the store 1 by the blower and finally as a function of the humidity value of the blower 5 sucked in air surrounding the memory 1. To sense the temperature of the green fodder in the store 1, a temperature sensor 9 is provided, which is designed as a lance that can be inserted into the green fodder and is provided with a handle 10 to facilitate handling. To this lance in memory 1 To be able to insert, the storage 1 has in its side wall 11 an opening suitable for this lance. The temperature sensor 9 is connected via a measuring line 12 to a measuring transducer located in the control circuit 6. The measurement of the air blown into the memory 1 by the blower 5 is carried out by means of a further temperature sensor 13, which is arranged at the outlet of the blower 5, for example in the space formed between the bottom 3 and the grate 4, and to the transmitter of the control circuit 6 a further measuring line 14 is connected. The measurement of the atmospheric humidity of the ambient air sucked in by the blower 5 is carried out by means of a moisture sensor 15, for example a conventional hygrostat, which is arranged in the vicinity of the intake manifold of the blower 5 but outside the accumulator 1 and connected to the control circuit 6 via a line 16 is. Furthermore, a further temperature sensor 17 can be provided for measuring the temperature of the air surrounding the memory 1, which temperature sensor is connected via a measuring line 18 to the transducer of the control circuit 6.

Using the example of drying conventional green fodder, this system works as follows:

After the possibly pre-dried green fodder has been introduced into the store 1, a preliminary ventilation takes place for a predetermined time, e.g. some hours. During this pre-ventilation, the control circuit 6 does not perform a control function on the blower 5, which thus continuously blows air into the memory 1 during the pre-ventilation.

After this pre-aeration, the control circuit 6 switches on automatically and measures the temperature both in the storage 1 forming a forage stock, that is to say the temperature of the green fodder therein by means of the temperature sensor 9, and the temperature of the ambient air by means of the temperature sensor 17 A continuous measurement of the humidity of the ambient air by means of the humidity sensor 15. Depending on these measured values, the ventilation is now controlled as follows: If the humidity of the ambient air is below a predetermined limit value, for example 65%, the green is initially ventilated feed by means of the blower 5 for a predetermined starting time, for example five days. However, this ventilation takes place at intervals, approximately every 2.5 hours for 15 minutes each. This ensures that the green fodder is dried gently, so that it retains its valuable nutrients and remains loose, meaning that it is not subject to any significant compression. If the air humidity measured by means of the moisture sensor 15 rises above the predetermined limit value, the control circuit 6 switches off the initial ventilation by means of the blower 5, since a sensible drying of the green fodder in the store 1 in the case of high air humidity in the ambient air (for example in rainy weather) is not possible in a targeted manner is. Avoiding unnecessary blower operation saves energy. If the air humidity drops again below the predetermined limit value, the interval operation of the blower 5 is switched on again.

However, the temperature of the green fodder in the store 1 is always monitored, even when the fan 5 is switched off. If this temperature exceeds a predetermined limit, e.g. 30 ° C, so that thermal damage to the valuable nutrients of the feed is to be feared, then the fan 5 is switched on, even if the air humidity is high on the outside. In this case, the air blown into the storage 1 by the blower 5 is not used to dry the green fodder, but to dissipate the heat generated in the green fodder 1. This blower operation, which may also be carried out at intervals, only takes place until the cooling of the feed in the store 1 has progressed to such an extent that a lower limit of the temperature, e.g. 24 ° C, is reached in the feed. The fan then remains switched off, provided the outside air humidity is above the predetermined limit. If the temperature in the feed rises again above the predetermined higher limit value (e.g. 30 ° C), then the blower is operated again until the lower temperature limit value is reached, etc.

This operation is maintained until, by measuring the temperature of the feed by means of the temperature sensor 9 and the temperature of the air blown in by the blower 5 by means of the temperature sensor 13, there is no longer a large difference between these two temperatures, and for a longer period of time , e.g. 1.5 hours. This temperature interval is predetermined; it can be assumed to be around 3 to 5 ° C for common green fodder.

In order to determine this temperature interval, the control circuit 6 a suitable circuit 26. If the temperature difference mentioned lies within this interval, this is an indication that the green fodder in the store 1 has reached a sufficient degree of drying, so that temporarily no further ventilation is necessary. However, this degree of dryness can change, for example due to a change in the atmospheric humidity of the environment (rainy weather) or through subsequent filling of the store 1 with a further quantity of green fodder.

If the temperatures in the feed and at the blower outlet are within the predetermined temperature interval, then - as already mentioned - the ventilation of the feed is switched off. However, the measurement of the temperatures mentioned is carried out continuously by the control circuit 6. As long as the temperature difference mentioned remains in the predetermined temperature interval, no ventilation needs to be carried out. However, if the predetermined temperature interval is exceeded, interval ventilation is again carried out - as described at the beginning - until the temperature in the store 1 has stabilized again, i.e. the predetermined temperature interval is maintained again.

It would be conceivable for different temperatures to be set in the store 1, for example due to different degrees of drying of feed quantities introduced at different times, or due to local fermentation processes, or due to different densities of the feed material, etc. Even though generally more than one temperature sensor 9 in the Storage 1 is introduced, the lances of these temperature sensors 9 expediently piercing the storage 1 from different sides and lying at different heights, so incorrect measurements could nevertheless occur. In order to avoid this, once the stabilization state has been reached, ie if the temperatures measured by the temperature sensors 9, 13 result in a temperature difference that lies in the predetermined interval, a brief ventilation is carried out from time to time, for example once a day for a few minutes. for a period of about two weeks. Due to the short-term air injection, the heat in the store 1 is raised and driven to the temperature sensor 9 or to the temperature sensors 9, so that any heat development in the store 1 is reliably indicated.

If a high level of air humidity occurs during this period of about two weeks, for example as a result of rainy weather, there is usually a heating in the store 1, which is determined by the temperature measurement of the temperature. temperature sensor 9 is reported. The temperature in the store then exceeds the predetermined upper limit, for example 30 ° C., so that in order to avoid damage to the green fodder, the blower 5 is switched on again by the control circuit 6 and sucks in air from the outside and presses it into the store 1. This air is then moist and therefore cannot dry the feed, but it absorbs heat from the feed in the store 1 and therefore cools this feed. The fan 5 remains switched on until the lower temperature limit (for example 24 ° C.) is reached. A certain fermentation process in storage 1 should be retained, because otherwise the feed tends to rot. If the lower temperature limit is reached, the fan is switched off. The temperature in the store 1 thus fluctuates between the two limit temperatures.

If a lower air humidity occurs again, the control circuit 6 returns to normal operation, i.e. at certain intervals the temperature difference between the two sensors 9, 13 is measured and, depending on this, the feed is aerated or not.

The control circuit 6 expediently has a display on which the respective temperature values or the respective operating state of the system can be seen. This enables visual control. An alarm device monitors the function of all measuring points and their connections, including the blower 5.

By means of the temperature sensor 17 measuring the outside temperature, the blower can be switched off via the control circuit 6 ^{″ in} order not to have to ventilate unnecessarily when the outside temperature is warm.

In the embodiment according to FIG. 2, the system has two stores 1 which are arranged next to one another. Each store 1 is essentially constructed as shown in Fig.l, but both stores 1 are supplied with air by a common fan 5 and alternately. For this purpose, a distribution device 19 is connected to the pressure nozzle of the blower 5, which has a distributor housing 20 which is connected to the interior of the two stores 1, expediently with the cavity located below the respective grate 4. Here, the fan 5 is therefore arranged outside the two stores 1. A flap 21 is pivotally mounted in the distributor housing 20 about a vertical axis 22. For this flap 21, a servomotor 23 is provided, which is provided by the control circuit 6 with electrical energy is supplied when the flap 21 is to be changed over. This is possible between two limit positions, which are secured by stops 24. In the right limit position of the flap 21, shown in full lines, the left accumulator 1 is supplied with air from the blower 5, in the left limit position of the flap 21 shown in dashed lines, on the other hand, the right accumulator 1. Of course, there are separate temperature sensors 9 for each memory 1 provided, in the illustrated embodiment two temperature sensors per memory 1. However, only a single temperature sensor 13 is required for the air blown into the distributor housing 20 by the blower 5.

Such a system is not limited to the operation of the same types of green fodder; rather, different types of crops or quantities of fodder introduced at different times can be stored in the two stores 1. By suitable programming of the control circuit 6, the drying and monitoring operation mentioned at the outset can be easily extended to two or, if appropriate, also more memories 1. The respective operating states can again be seen on the display 25 of the control circuit 6. As FIG. 3 shows, the blower 5 can be detachably connected to the distributor housing 20 in order to facilitate the cleaning of the distributor device 19 and, if appropriate, also of the blower 5. For this purpose, the distributor housing 20 has fastening devices 28 on its wall facing the blower 5 next to the blowing opening 27, which cooperate with analog fastening devices 28 ′ of the housing of the blower 5. For example, the fastening devices 28 can be formed by slots into which hooks 28 'can be hung. The housing of the fan 5 has a lateral suction opening 29 which is covered by a grille. The direction of the sucked-in air is indicated by an arrow 30, the pivoting direction of the flap 21 by a double arrow 31. The direction of flow of the air conveyed into the blowing opening 27 by the fan 5 is illustrated by arrows 32.

The memory can be large, e.g. as a silo.

Claims

Claims: 1. A method for drying green fodder for animals, such as grasses, clover, rapeseed, etc., air being blown into the green fodder stored under the roof for a predetermined time, in particular several hours, as a pre-aeration and then the temperature after it has been introduced using a blower of the green fodder and the moisture of the air sucked in by the fan are measured and compared with predetermined limit values in an electrical circuit for controlling the blower operation, characterized in that after the pre-ventilation, initial ventilation is carried out as a function of the moisture in the air sucked in by the fan and that after this initial ventilation the temperature of the air supplied to the green fodder is also measured and the blowing of the air into the green fodder is also controlled as a function of the difference in the temperatures of the green fodder and the air blown into it so that the blowing in is interrupted by air as soon as the mentioned temperature difference within a predetermined interval, e.g. 3 ° C for a predetermined time, e.g. 1.5 hours remains. 2. The method according to claim 1, characterized in that the air is blown in at intervals, e.g. every 2.5 hours for 15 minutes. 3. The method according to claim 1 or 2, characterized in that the air injection into the green fodder is interrupted when the temperature of the green fodder a predetermined value, e.g. 24 ° C, falls below. 4. The method according to any one of claims 1 to 3, characterized gekennzeich¬ net that when a predetermined limit of the humidity (e.g. 65%), the initial ventilation is only carried out when the temperature of the green fodder exceeds the predetermined temperature value. 5. The method according to any one of claims 1 to 4, characterized in that when the air humidity falls below a predetermined limit (for example 65%), the initial ventilation, preferably at intervals, is carried out until the aforementioned temperature difference remains within the predetermined temperature interval and or or the air humidity rises again above the predetermined limit. 6. The method according to any one of claims 1 to 5, characterized gekennzeich¬ net that even at temperature values within the temperature interval a brief ventilation takes place at predetermined time intervals, for example once a day for a few minutes. 7. Device for carrying out the method according to one of claims 1 to 6, with a storage (1) for the green fodder provided with a roof (2), a blower (5) for ventilation thereof, a temperature sensor (9) for measuring the temperature of the green fodder, a moisture sensor (15) for measuring the air humidity of the air drawn in by the blower (5) and with an electrical control circuit (6) which switches the blower (5) on as a function of the measured temperature and humidity values or switches off, characterized in that at least one further temperature sensor (13) is provided for measuring the temperature of the air blown in by the blower (5) and in that the control circuit (6) has a circuit (26) for forming the difference between this temperature and the temperature of green fodder. 8. The device according to claim 7, characterized in that there is also a temperature sensor (17) for measuring the temperature of the air to be sucked in by the fan. 9. Apparatus according to claim 7 or 8, characterized in that more than one store (1) is provided for the green fodder, wherein for each store (1) at least one temperature sensor (9) is provided for the green fodder located in this store (1) and this store (1) is connected to a distribution device (19) connected to the pressure port of the common blower (5) for the air conveyed by the blower (5). 10. The device according to claim 9, characterized in that the distribution device (19) in a distributor housing (20) pivotally mounted flap (21) and a drive, e.g. has a servomotor (23) for this flap (21), which is actuated by the control circuit (6).