Background

The present invention relates to an air mixing system for a broiler house.

In general, an air mixing system, its use and method for mixing air are disclosed in earlier patent NL-1.023.266C2 of the current applicant. The system has proven to be extremely successful and is able to provide a good climate regarding temperature and humidity. It improves the air quality at the floor level or level of the animals, thus increasing animal performance. Furthermore, material on the floor, like dung or manure and straw, is dried in order to avoid high ammonia concentrations and emissions.

Summary of the Invention

The invention aims to improve the current air mixing systems.

Another object of the invention is to reduce the exhaust of the discharge of dust, in particular air-borne solid particles, in particular particulate material known as for instance PMlO, or PM2,5, from the farming industry, in particular the poultry industry.

According to a first aspect of the invention this is realized with an air mixing system for a poultry house or broiler house, comprising a set of air mixing devices, said air mixing devices each comprising a shaft with an inlet for air and an outlet for air, connecting means for connecting said shaft vertically in a poultry house or broiler house, a propulsion unit in said shaft between said inlet and said outlet for propelling air from said inlet to said outlet, an ionization unit arranged in said shaft for in operation charging particles carried in a flow of air running from said inlet to said outlet, and a particle collecting surface arranged near said outlet for in operation capturing said charged particles. In general, the use of ionization units in farming are known as such for treating air exhausted or air inside the animal house in order to reduce odour. Applicants came to realise that their current air mixing system, known in the market as the "Mixlucht systeem" which is used in broiler houses, circulated a large volume of air. They thus developed the internal air mixing system for use in broiler houses and that mitigates the emission of both fine dust and ammonia to ambient air, and increases animal performance by improving the air quality at the living level of birds. The modification of known air mixing systems enables the removal of fine dust and diminishes the concentration of airborne microbes throughout the broiler house. In fact, in the invention a large volume of slow moving air can be treated very effectively.

In an embodiment, said ionization unit is arranged between said propulsion system and said particle collecting surface. In that way, the whirling air below the propulsion system can have a beneficial effect on the charging of (dust) particles.

In an embodiment, said particle collecting surface has an electrically conductive surface and means for grounded said surface. In an embodiment, it comprises a grounding lead coupling said conductive surface with ground, or with another defined potential which differs from the potential of the ionization unit.

In an embodiment, said air mixing devices further comprise a cleaning system for cleaning the surface of the collecting surface. The cleaning system can comprise a rinsing unit for applying, in an embodiment spraying, water on the collecting surface for removing collected dust and particles. In another embodiment, the cleaning system comprises a mechanical dust and particles removal system. For instance, a moving brush can be installed.

In an embodiment, said air mixing devices comprise a deflector at the air outlet arranged to provide a circumferential slit, a surface of said deflector in said air outlet providing said particle collecting surface. In an embodiment, said deflector comprises a plate with its normal in line with the longitudinal direction of said shaft at an end of said shaft, or a cone. It should be noted that the above wording should be read in such a way as to also include a plate is almost perpendicular to the longitudinal direction of the shaft. It can this also be a little inclined, as long as the function of the plate, which is deflecting the air for the shaft, is maintained. As described in the drawings, the plate may comprise a cone. The cone is in an embodiment positioned with a rotational axis in line with the axis of the shaft.

In an embodiment, said connecting means comprise a cable at one end attached near one end of a shaft, and at the other end coupled to a roof of a poultry house or broiler house, in an embodiment said cables are coupled to the roof via a hoisting system for changing the height of the air mixing devices. Thus, the height of the air mixing devices above the floor can be set. It should be clear that "a cable" in this respect comprises one cable but also more than one cable. Furthermore, when the air mixing devices have been hoisted up, the floor of poultry house or broiler house can be cleaned easily.

Alternatively the invention provides an air mixing device for an air mixing system for a broiler house, comprising a shaft with an inlet for air and an outlet for air, a propulsion unit in said shaft between said inlet and said outlet for propelling air from said inlet to said outlet, an ionization unit arranged in said shaft for in operation charging particles carried in a flow of air running from said inlet to said outlet, and a particle collecting surface or collecting surfaces arranged near said outlet for in operation capturing said charged particles.

Furthermore, the invention provides a method for controlling the climate in a broiler house, said method comprising providing an air mixing system described above, providing a voltage to said ionization unit and operating said propulsion unit for mixing air in said broiler house.

The invention further provides an air mixing device comprising a shaft with an inlet for air and an outlet for air, connecting means for connecting said shaft vertically in a poultry house or broiler house, a propulsion unit in said shaft between said inlet and said outlet for propelling air from said inlet to said outlet, an ionization unit arranged in said shaft for in operation charging particles carried in a flow of air running from said inlet to said outlet, and a particle collecting surface arranged near said outlet for in operation capturing said charged particles. In an embodiment, said shaft comprises a circular tube part or pipe part. In an embodiment, one end is substantially open. This end provides an air inlet opening. At or near the other end, a plate may be provided in such a way to provide a circumferential slit. The slit may be provided in such a way, for instance using the cone described above, to provide air flowing between 90 and 45 degrees with respect to the axis of the shaft in downward direction (in operation).

It should be evident from this description that the air mixing devices, in particular when comprising the end plate, can be operated in one of the following two modes. Usually, the shafts or ducts are pending in vertical from the ceiling. In a first mode, the air inlet is at or near the ceiling end and the air outlet is near the floor end. This is the usual way the air mixing device will be used, thus providing fresh, clean air to the animals. Alternatively, the air inlet can also be near the floor end and the air outlet can be near the ceiling. Thus, the device still mixes air, and is still capable of removing particles. In this mode, the air can be ionised by flowing along the plate or cone, or using separate ionising provisions like plates downstream of the air inlet, or downstream of the plate or cone. In such an embodiment, the particle collecting surface will again be positioned near the air outlet.

The invention further relates to an apparatus comprising one or more of the characterising features described in the description and/or shown in the attached drawings, and/or a method comprising one or more of the characterising features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Various aspects can further form the basis for one or more divisional applications.

Description of the Drawings The invention will be further elucidated referring to an embodiment of an air mixing system shown in the attached drawings, showing in:

Figure 1 a top view of a broiler house with an air mixing system; Figure 2 a side view of the broiler house of figure 1; Figure 3 a side view of a row of air mixing devices; Figure 4 a side view of an air mixing device; Figure 5 a cross section of an end part of an air mixing device.

Detailed Description of Embodiments

First, the patented air mixing system of NL- 1.023.266C2 is described. As described in that publication, it was found that using such an air mixing system for ventilating a poultry house or broiler house, for instance, this would dry the dung or manure collected on the floor. Thus, the exhaust or forming of ammonia can be limited. In fact, the dry matter contents of material collected on the floor can be above 65 %.

As mentioned in that patent, the lower end of the air mixing devices will be positioned about 50-180 cm above the floor in a poultry house or broiler house. In use, each air mixing device will cover about at least 100 m ² floor area. The air mixing devices described in the patent each have a capacity of about at least 40 m ³ /hr. In an embodiment, the poultry house or broiler house will further comprise floor heating. The air mixing system further comprises a control unit for controlling the air mixing devices. The air mixing system further comprises sensors operationally coupled to the control unit. The control unit controls, amongst others, the temperature at animal level.

Figure 1 shows a top view of a broiler house 1. In this broiler house 1 with longitudinal walls 2 and transverse walls 3, vertically oriented air mixing devices 4 are attached to the ceiling. Figure 2 shows a side view of a broiler house 1 which has ventilating units 5 in the transverse walls to exhaust air from the broiler house. Figure 3 illustrates a setup of an embodiment of air mixing devices 4. In the embodiment shown, these air mixing devices are arranged in two parallel rows in the length direction of the broiler house. Each device covers about 150 m ² of floor space. In the usual setup, the broiler house 1 has air inlets and air outlets for circulating fresh air through the broiler house. The air mixing devices comprise cables 7 attached to the upper part 6 of the air mixing devices 4. It is evident that in stead of one or more cables, it is also possible to use rods. Cables, especially when combining them with one or more pulleys, allow easy adjustment of the position of the devices. Each air mixing device 4 has an air propelling unit 10, usually a ventilator. Furthermore, each air mixing device 4 has a lower end 8. The air mixing devices 4 are mounted freely above floor 9 at a height h. This height is selected in such a way that the animals on the floor 9 receive enough fresh air and the material on the floor is dried as quickly as possible. On the other hand, the flow of air should be minimal. In fact, as soon as the flow of air gets too strong, (young) chickens or poultry will leave the spot where the flow of air gets too strong. In a broiler house, this will lead to unoccupied areas on the floor. In practice, the height h will be about 50-180 cm.

In order to further dry the material on the floor, and in order to improve the climate for the animals, the floor can be heated using a floor heating system 16. This floor heating system 16 as such is known in the art.

Figure 4 shows a cross-sectional view of an embodiment of an air mixing device 4 comprising a dust-removal unit. Each air mixing device 4 comprises a (in operation) vertical shaft 11. This shaft thus functions as an air-shaft or ventilation shaft. The shaft 11 can have any shape of cross section. In practice, often a round cross section is selected for practical purposes.

The shaft 11 has an upper passage at upper part 6 and a lower passage at lower end 8. Usually, the upper passage will be used as air inlet and the lower passage will form an outlet for air. Furthermore, the shaft 11 is provided with an air propulsion unit. Usually, a fan 10 is used. In an embodiment, the fan is operationally coupled to the control unit described above. In an embodiment, it controls the speed of the fan.

Usually, the speed of the fan is slow, as the flow rate of the air is low. In operation, the flow rate of one device is about 40 - 7000 m ³ /hr. Usually, the shaft 11 will have a cross sectional area of between about 0.025 - 1.5 m ² . In most of the installed systems, the shaft 11 will have a sectional area of about 0.1 - 1 m ² . In practice, the shaft 11 is a round tube. Usually, one device is installed for about each 100-150 m ² of area in a broiler house or poultry house. In order to be able to spread air evenly, and thus avoid detrimental airflow to an extent that it discomforts the animals, lower end 8 of the shaft 3, which in operation is located in the vicinity of the animals, is provided with a flow regulator 12 (Figure 5).

In this embodiment, the fan 10 is installed below the inlet at the upper part 6 that draws warm air from the top level of the broiler house 1. Subsequently, the fan 10 transports it through the shaft 11 , and distributes it evenly spread at animal living level via flow regulator 12. The flow regulator provides a circumferential slit, thus allowing air to flow from or to all directions.

Figure 5 shows a detail of the lower end 8 of the air mixing device 4. In a simple embodiment, the flow regulator may comprise a plate with its normal aligned with the longitudinal direction of the shaft 11. It is here spaced from the lower passage. Thus, in a very simple way a circumferential slit is provided. In an embodiment, flow regulator 12 comprises a conically shaped plate 13 at the lower end 8 of the shaft 11.

In operation, the fan 10 creates circulating air flow through shaft 11. The circulating air stimulates drying of the litter on the floor via warm air from the top that is distributed over the litter surface. This drying prevents the formation of ammonia from uric acid in the manure. Besides improving the air quality by avoiding the building up of ammonia concentration, the air quality is improved by removal at animal living level of metabolic carbon dioxide and water vapour. In addition, the particle removal unit incorporated in the air mixing devices provides removal of particulate material.

The air mixing devices 4 known as such are in an embodiment modified in the following way. Inside the shaft 11 an ionization device V is provided. In an embodiment, a circular shaped ionization unit V is placed downstream of fan 10. In this embodiment, the ionization unit V is places just below fan 10. The ionization unit V uses a high voltage to produce ionized air. The ionized air of the ionization device V produces negatively charged molecules that charge passing airborne particles, like dust particles. This charging process is intensified by the strong air turbulence just after the fan 10. The air with charged dust particles will pass through flow regulator 12. In this embodiment, the flow regulator 12 is grounded. This causes the charged dust particles to precipitate on the particle collecting surface 13 of flow regulator 12.

In the embodiment detailed in figure 5, flow regulator 12 comprises a conically shaped plate 13. The conically shaped plate 13 is attached at a distance from the outlet 8 of shaft 11. Furthermore, in this embodiment a narrow outlet slit 14 is provided between a slightly curved edge of the shaft 11 and the conically shaped plate 13 as depicted in figure 5. The height of the slit can be set, usually between about 5 cm and about 10 cm. In an embodiment, the conically shaped plate 13 has a electrically conductive surface. Thus, the surface provides a particle collecting surface 13. In an embodiment, the conically shaped plate 13 is a metal plate. This plate 13 can be grounded and the charged dust particles will be attached to its surface. A small width of the outlet slit 14 ensures the charged particulates to pass the grounded surface 13 at close distance and will guarantee a high removal efficiency of fine dust from the air. To improve the removal rate of fine dust more conically shaped plates can be installed.

In an embodiment, at regular time intervals collected particles on the surface 13 are removed to maintain the electrostatic attachment of passing particles. This removal may be automated in a process in which at regular time intervals (hourly or more frequent if required) the ionization system and grounding of the particle collecting surface are turned off for a few seconds. The dust particles from the surface can subsequently be collected by drawing air into a circular tube, placed at the outlet ring, that is evacuated by a vacuum pump. Alternatively, the surface 18 can be rinsed with water. Alternatively the cone surface is sprayed for a few seconds with water. The dripping water can be collected below the plate 13. In an embodiment, this water with collected particles is collected at the rim of plate 13.

The application of the described method and system provides the following advantages compared to the mere implementation of ionization devices and grounding surfaces in the top layer of the broiler house, without air circulation:

1. By forced air circulation as described, the intensity of treatment of the air by ionization and subsequent attachment to a grounded surface is strongly increased and the chance that untreated air leaves the house is much smaller than without internal air circulation.

2. By placing the ionization unit just after or downstream of the fan, use can be made of the fan turbulence. The effects of the ionization will be amplified by the strong mixing or turbulence of air.

3. By directing or propelling all the ionized air directly to a grounded surface at the outlet of the shaft, the chance that charged particulates will leave the house is much smaller than in applications without air circulation. 4. Charged particles are removed at the outlet of the shaft. This prevents the spreading of charged particles collected on the particle collecting surfaces throughout the house. Heavy dust loading on surfaces, as seen in open application of ion generation may cause malfunctioning of equipment, and increases the risk of re- entering of charged particles into the air by animal movement.

5. Implementing the dust removal application in vertical shafts for air circulation gives an extra utilization of the energy invested in the drying of the top litter layer.

6. The proposed system can be more easily provided with an automated cleaning system because collected dust is locally concentrated at the outlets of a restricted number of ventilation shafts.

7. A large volume of relatively slow moving air can be treated, thus improving the effectiveness of removal of particulate material.

It will also be clear that the above description and drawings are included to illustrate some embodiments of the invention, and not to limit the scope of protection. Starting from this disclosure, many more embodiments will be evident to a skilled person which are within the scope of protection and the essence of this invention and which are obvious combinations of prior art techniques and the disclosure of this patent.