The present invention relates particularly to a device as according to the preamble of claim 1.

The applicant markets such a device for application in separating manure in the cattle farming industry. The known device is provided with a so-called outflow membrane arranged close to the opening of the second outlet for the solid substance and adapted to provide a self-regulating counter-pressure to the solid fraction leaving the device. Prior to the known device being taken into use the dimensions of the outlet opening have to be set. During use the dimensions are to some extent flexible because the outflow membrane is formed by flexible elements which co-displace in the flow direction of the solid fraction.

The solid fraction of manure is reused in cattle farming, for instance as cubicle litter. High quality standards are set for this cubicle litter, among other ways in respect of the dry matter content.

The present invention has for its object to provide an improved device of the type stated in the preamble which can comply with the highest quality standards in respect of the end product, i.e. the solid fraction.

The device according to the invention has for this purpose the feature that the device is further provided with measuring means for measuring one or more operational parameters of the first drive and a control device for setting the dimensions of the opening on the basis of the measured values for the one or more operational parameters, that the head comprises a number of co-acting plate elements which define the dimensions of the opening, and a second drive for moving the plate elements, which second drive is connected to the control device, wherein the plate elements are disposed substantially for movement in the plane of the opening and wherein the shape of the plate elements is complementary.

The device according to the invention is able during use to set the outlet opening for the solid substance while taking into account operational parameters of the drive of the separating means. The operational parameters can be chosen and the control device set such that, in the case the solid fraction is too thin, the outlet opening is automatically made smaller and that, in the case the solid fraction is too thick, the outlet opening is automatically made larger. This means that the device according to the invention can be effectively prevented from becoming clogged. The separating process proceeds wholly automatically and the device functions autonomously. The quality of the solid fraction, and particularly the dry matter content thereof, can moreover be guaranteed. The co-acting plate elements open and close in a manner similar to a diaphragm in a photo camera, although without overlap, and together define the opening of the second outlet. The plate elements can be actively controlled by means of a second drive which is connected to the control device.

It is noted that a device as according to the preamble of claim 1 is likewise known from WO 96/08364 and FR 1401378. Use is however made in both known devices of a pressure gauge for measuring the pressure in the device, on the basis of which the size of the opening is set. The pressure gauge is an extra component which makes the known devices more complex and more susceptible to malfunction. Furthermore, neither of the known devices discloses the co-acting plate elements of complementary form as described in the characteristic of claim 1.

In a preferred embodiment the outer ends of the plate elements are formed such that in the extreme position an opening remains clear for a throughfeed pipe for separating extra liquid. A second liquid outlet is hereby created.

According to a preferred embodiment the first drive is an electric motor, the measuring means are adapted to measure the electric current in the electric motor and the control device is adapted to automatically set the dimensions of the opening on the basis of the measured electric current. This can take place both continuously and at predetermined time intervals. An electric motor is a reliable drive for the auger. The power used or required by an electric motor is related to the electric current, which therefore forms a suitable operational parameter within the context of the present invention.

In a further development the head is provided with a disc on which the plate elements are mounted, wherein the head is provided with means for relative rotation of the disc and the plate elements by means of the second drive. The choice of a disc with rotatable plate elements results in a compact design.

In a first variant of the head the disc is provided with a number of slots, wherein each plate element is provided with a mounting point for translation in one of the slots, wherein the head is provided with a

transmission for rotation of the disc relative to the plate elements by means of the second drive. The first variant has the significant advantage that it can be cleaned very well.

In a second, alternative variant of the head each plate element is provided with a mounting point for rotatable mounting on the disc, wherein the head is provided with a transmission, such as a gear rim, for rotation of the plate elements relative to the disc by means of the second drive.

The invention further relates to a head with an opening of adjustable dimensions as described as part of a device according to the invention.

The invention will now be further elucidated with reference to the accompanying figures, in which:

Figure 1 shows a cross-sectional view through a device according to the invention;

Figures 2A to 2C show cross-sectional views through a first preferred embodiment of a head of the device according to figure 1 ; and

Figures 3A to 3C show cross-sectional views through a second preferred embodiment of a head of the device according to figure 1.

In the shown preferred embodiment device 1 is intended for the purpose of separating manure into a liquid fraction and a solid fraction.

Device 1 is provided with a housing 2 in which separating means 6 are arranged. In the shown preferred embodiment the separating means comprise an auger 6, preferably of plastic. Housing 2 is provided with an inlet 3 for the manure and, connected to inlet 3, a pressure chamber 9 with a first outlet 4 for the liquid fraction and a second outlet 5 for the solid fraction. A first drive 8 is arranged for driving of auger 6. In the shown preferred embodiment drive 8 is an electric motor. Such a device is also known in the field as a screw press/pump.

According to the invention second outlet 5 is provided with a head 10, 100 with an opening 1 1 , 1 1 1 for the solid fraction. Opening 1 1 , 1 1 1 has adjustable dimensions. Device 1 is further provided with measuring means (not shown) for measuring one or more operational parameters of the first drive 8. A control device 30 is connected to the measuring means and to head 10, 100 for the purpose of setting the dimensions of opening 1 1 , 1 1 1 on the basis of measured values for the one or more operational parameters.

Figures 2A to 2C and 3A to 3C show respectively two variants of a head 10 and 100 according to the invention. In both variants head 10, 100 comprises a number of co-acting plate elements 12, 1 12 which define the dimensions of opening 1 1 , 1 1 1. Head 10, 100 is always provided with a second drive 18, 1 18 for moving plate elements 12, 1 12. Second drive 18, 1 18 is connected to control device 30.

Figures 2A to 2C and 3A to 3C show cross-sectional views of both embodiments, wherein plate elements 12, 1 12 occupy different positions and, as a result, opening 1 1 , 1 1 1 has different dimensions in each case.

In both embodiments plate elements 12, 1 12 are disposed

substantially for movement in the plane of opening 1 1 , 1 1 1 . In other words, plate elements 12, 1 12 are disposed substantially transversely of the throughfeed direction of the solid fraction in housing 2.

In the first preferred embodiment, which is shown in figures 2A to 2C, head 10 is provided with a disc 13 on which plate elements 12 are mounted. Head 10 is provided with means for relative rotation of disc 13 and plate elements 12 relative to each other by means of second drive 18. This is likewise the case for the second preferred embodiment, which is shown in figures 3A to 3C. In the first preferred embodiment disc 13 is provided with a number of slots. Each plate element 12 is provided with a mounting point 19 which is arranged for translation in one of the slots 14. Head 10 is provided with a transmission 16 for rotation of disc 13 by means of second drive 18. As disc 13 moves the plate elements 12 are forced to co-displace to the desired position, in which they define an opening 1 1 with the desired dimensions.

In the shown first embodiment the transmission comprises a pinion 16. Disc 13 is provided with a toothing 23 for co-action with the pinion.

In the second preferred embodiment, which is shown in figures 3A to 3B, each plate element 1 12 is provided with a mounting point 129 for rotatable mounting on disc 1 13. Head 100 is provided with a transmission 125 for rotation of the plate elements relative to the disc by means of second drive 1 18. In the shown second preferred embodiment the transmission comprises a gear rim 125 arranged on the peripheral edge of head 100. Gear rim 125 engages on a toothing 124 arranged on each plate element 1 12. The transmission further comprises an actuator 1 18 which is connected by means of two arms to gear rim 125 on one side and to disc 1 13 on the other. This actuator 1 18 fulfills the function of the second drive. Rotation of plate elements 1 12 defines an opening 1 1 1 with the desired dimensions.

Using a suitable control loop the process of manure separation in device 1 can be automatically monitored, and the desired dimensions of outlet opening 1 1 , 11 1 can be adjusted on the basis of measured values for operational parameters of first drive 8. These operational parameters will be related to the composition of the supplied material, in this example manure. If the supplied material is very thin, the drive will use little power. An operational parameter value related to the power required by the drive, for instance the electric current in an electric motor, will then decrease. If the decrease exceeds a predetermined margin, the dimensions of the respective opening 1 1 , 1 1 1 in the respective head 10, 100 will be reduced by generating a corresponding signal in control device 30 and sending it to the respective second drive 18, 1 18. Conversely, if the composition of the material, in this example manure, is thicker, the first drive will require more power, i.e. for instance the electric current in an electric motor will increase. If the increase in the relevant operational parameter related to the power of the drive, such as the electric current, exceeds a predetermined margin, control device 30 will generate and send a signal to the respective second drive 18, 1 18 for the purpose of adjusting the respective plate elements 12, 1 12 such that the dimensions of opening 1 1 , 1 1 1 in head 10, 100 become greater. In the case of decreasing dimensions of opening 1 1 , 1 1 1 the counter-pressure in pressure chamber 9 of housing 2 will increase, whereby more liquid is removed from the material. The dry matter content of the solid fraction leaving outlet 5 will increase. Conversely, in the case of increasing dimensions of opening 1 1 , 1 1 1 the counter-pressure on the solid fraction in pressure chamber 9 will decrease, whereby the dry matter content of the solid fraction from outlet 5 decreases. By actively setting the dimensions of the opening of outlet 5 it is possible to make allowance for changes in the composition of the supplied material. The device is able to function autonomously, providing a guaranteed quality of the solid fraction.

Control device 30 is provided with suitable hardware and/or software.

An example of a suitable control device is a PLC control. Control device 30 is preferably set to monitor the degree of change in the current measured value of the operational parameter. If the change exceeds a predetermined margin, the dimension of opening 1 1 , 1 1 1 has to be adapted thereto.

The first drive 8 is preferably an electric motor. The measuring means are adapted to measure the electric current in the electric motor. Suitable measuring means, such as inductive measuring means, are commercially available. The measured electric current is provided to control device 30 which is adapted to automatically set the dimensions of opening 1 1 , taking the measured value into account. The adjustment takes place by means of second drive 18, 1 18, which is preferably also an electric motor.

In the first preferred embodiment opening 1 1 is not completely closed in the extreme position of plate elements 12. A circular opening remains clear in figure 2A. This circular opening is formed by the special outer ends 12A of plate elements 12. This circular opening 1 1 is adjusted to a throughfeed pipe 44 which is present in a preferred embodiment of device 1 for the purpose of separating extra liquid. This throughfeed pipe 44 forms as it were a second liquid outlet. In figure 3A however, plate elements 1 12 completely close opening 1 1 1 in the extreme position. This embodiment is suitable for devices without pipe-like second liquid outlet. The two

embodiments can of course be combined. This means that head 10 as according to figures 2A to 2C can be provided with plate elements 1 12 of figures 3A to 3C and that head 1 1 1 as according to figures 3A to 3C can be provided with plate elements 12 of figures 2A to 2C.

In all embodiments the shape of the plate elements is complementary. The plate elements lie against each other without overlapping each other.

Although the device according to the invention is further illustrated with reference to a screw press, it will be apparent to the skilled person that other separating means can also be used in combination with the head with opening of adjustable dimensions according to the invention. This head 10, 100 can be generally applied to a solid substance outlet of a material separator, provided the condition is fulfilled that the separating means provide for a pressure which builds up in the direction of the outlet opening for the solid substance.

Further described is that the electric current of an electric motor is measured and serves as operational parameter in accordance with the inventive concept. It will be apparent to the skilled person that diverse other operational parameters can be measured and can be used to set the dimensions of the opening in the head according to the invention. Suitable operational parameters are for instance parameters related to the power currently used or required by the first drive. Within this context it will also be apparent that it is not essential for the first drive to be formed by an electric motor. Diverse other types of drive can be deployed in this device, for instance a hydraulic drive or a fuel engine.

The invention is not therefore limited to the shown and described preferred embodiments, but extends generally to any embodiment falling within the scope of protection of the appended claims, as seen in the light of the description of the figures.