DD293968A5 - CIRCUIT ARRANGEMENT FOR REGULATING THE DIFFERENTIAL SPEED BETWEEN THE CENTRIFUGAL DRUM AND THE FOUNDER CIRCUIT OF A COMBINATION CENTRIFUGE CENTRIFUGE - Google Patents

Abstract

The invention relates to a circuit arrangement for regulating the differential speed between the centrifuge drum and advancing screw of a solid bowl screw centrifuge and is primarily intended for solid bowl screw centrifuges, which are used for the separation of suspensions with varying solids content. The aim of the invention is to develop a circuit arrangement for regulating the differential speed, which is able, using simple and known technical means, to automatically regulate the speed difference between the drum and the worm, depending on the worm torque. According to the invention, the object according to FIG. 1 is achieved by tapping impulse-proportional impulses from the transmission (3) and sun gear (4) by means of initiators (1; 2) and directly via an integrator (5) as the actual value I of a control device (6) and in parallel an actual value II by a power socket (7) via a Meszverstaerker (8) of the control device (6) fed, the actual value I and actual value II in the control device (6) with a predetermined setpoint of the command equipment (9) to an analog signal for controlling a Rectifier actuator * whereby the power supply to an induction brake (11) is controlled in such a manner as to increase the power supply to increase the differential speed, the induction brake (11) being supported so as to be able to apply the load via a load measuring means (12) (7) the load as actual value II to the Meszverstaerker (8) and if necessary from here from an inflow control (13). Fig. 1 {solid shell screw centrifuge; Centrifuge drum; Auger; Differential speed; Differential speed control; sun gear; torque; Volume throughput; Load control; Screw centrifuge}

Description

Explanation of the essence of the invention

The invention has for its object to develop a circuit arrangement for regulating the differential speed between the centrifuge drum and screw a Vollmantelschneckenzentrifug6 that automatically regulates the differential speed between the drum and screw in dependence on the screw torque. With increasing torque, the differential speed must be increased, with falling torque, the Diffarenzdrehzahl must be reduced. Furthermore, the maximum torque should be used for a second independent and higher-level intake quantity control. The object is achieved in that speed proportional pulses tapped by initiators from the transmission and sun gear and fed directly via an integrator as the actual value I of a control device and an actual value Il parallel through a load cell via a measuring amplifier of the controller, the actual value I and actual value Il in the control device with a predetermined target value of the Kommandogerätes to an analog signal for controlling a rectifier actuator, whereby the power supply to the induction brake is controlled in such a way that an increase in the power supply leads to an increase in the differential speed is prepared , wherein the induction brake is mounted so that via a load measuring device, the load cell as the actual load value Il to the measuring amplifier and, if necessary from here from an inflow quantity control.

The function of this circuit arrangement is characterized in that the speed is used for a differential speed control of the transmission and sun gear and an influence on the feed rate is taken over the load cell. Furthermore, it is possible via sine switching device, after the solid bowl worm centrifuge drives continuously to switch from manual to automatic. The two control devices are also applicable individually. Thus, a solid bowl screw centrifuge can be equipped individually with a differential speed control or with a supply flow control. Both regulations achieve a dependent load regulation that ensures maximum utilization.

Another advantage of this solution is that the disadvantages known in the prior art are eliminated and ensures a continuous operating state and / or utilizes in terms of their work under the necessary requirements.

All values are necessary by measurements of all products to provide required safety ranges for torque and volume flow as well as a prior art.

Ausführungsbeisplel

The invention will be described below with reference to the accompanying drawings

Fig. 1: circuit arrangement for regulating the differential speed

explained.

The embodiment shown in Figure 1 represents the circuit arrangement according to the invention, wherein the differential speed between the drum and screw conveyor in practice is between 2U / min to 30U / min. The differential speed between the drum and auger should be as large as necessary for the transport of the resulting amount of solids, but at the same time as small as possible, so that the solids remain as long as possible on the conical part of the drum and well drained to achieve a low residual moisture value and also the solid sedimentation is disturbed as little as possible by turbulence. In this limit operation of the screw centrifuge but the risk of "Zufahrens" or "clogging" of the screw due to volume and / or concentration variations of the inlet is large. This optimum limit operation can only be operated if the differential speed between the drum and the screw can be measured very quickly and accurately and can be immediately adjusted to the value required from the instantaneous and measured solids load. It is therefore necessary, depending on the worm torque to automatically regulate the differential speed between the drum and screw. With increasing torque, the differential speed must be increased, be reduced with decreasing torque. The maximum torque value is to be used for a second independent and higher-level supply quantity control.

For this purpose, speed-proportional pulses are tapped by means of initiator 11 and initiator Il2 from the gearbox 3 and sun gear 4 and fed directly via an integrator 5 as actual value I of a control device 6 and parallel an actual value Il by a load cell 7 via a Meßwertverstärker 8 of the control device 6 , the actual value I and actual value Il in the control device 6 with a predetermined nominal value of the Kommandogerätes 9 to an analog signal for controlling a rectifier actuator 10, whereby the power supply to the induction brake 11 is controlled in such a way that an increase in the Power supply to increase the differential speed leads is processed, the induction brake 11 is mounted so that via a load measuring device 12, the load cell 7, the load as actual value Il to the measuring amplifier 8 and if necessary from here from an inflow amount control 13 takes place.

The function of this circuit arrangement is characterized in that the speed is used for a differential speed control of the transmission 3 and the sun gear 4 and on the load cell 7, an influence on the feed rate is taken. Furthermore, it is possible via a switching device 14, after the solid bowl worm centrifuge 15 drives continuously to switch from manual to automatic. The two control devices are also applicable individually. Thus, the solid bowl screw centrifuge 15 can be individually equipped with a differential speed control or with a supply quantity control 13. By both regulations, a dependent load control is achieved, which ensures maximum utilization.

Another advantage of this solution is that the disadvantages known in the prior art are eliminated and ensures a continuous operating state and / or utilizes in terms of their work under the necessary requirements.

All values are required by measurements of all products to provide required safety ranges for torque and volume flow as in the prior art.

Claims (1)

Circuit arrangement for regulating the differential rotational speed between the centrifuge drum and screw conveyor of a solid bowl screw centrifuge, characterized in that speed-proportional pulses are tapped by means of initiators (1, 2) from the gearbox (3) and sun gear (4) and directly via an integration member (5) as actual value I a Control device (6) and parallel an actual value Il by a load cell (7) via a measuring amplifier (8) of the control device (6), the actual value I and actual value Il in the control device (6) with a predetermined desired Value of the command device (9) to an analog signal for controlling a rectifier actuator (10), whereby the power supply to an induction brake (11) is controlled in such a way that an increase in the power supply leads to an increase in the differential speed is processed, the Induction brake (11) is mounted so that a load measuring device (12) the load cell (7) the load as actual who t Il to the measuring amplifier (8) and if necessary from here from an inflow quantity control (13). For this 1 page drawing Field of application of the invention The invention relates to a circuit arrangement for regulating the differential speed between the centrifuge drum and screw conveyor of a solid bowl screw centrifuge and is primarily intended for solid bowl screw centrifuges, which are used for the separation of suspensions with varying solids content. Characteristic of the known state of the art According to DE-OS 2551789 a Vollmantelschneckenzentrifuge is known in which the drive of the centrifuge drum and the screw conveyor are connected via pressure lines with three pump units, which are driven by a drive motor. The regulation of the differential speed between the centrifuge drum and the screw conveyor takes place in dependence on the torque of the screw conveyor and / or the centrifuge drum by changing the pressure fluid quantities by means of control valves. The disadvantage of this solution is that the differential speed control, a high cost of pumping units, pressure lines and the like is necessary. Since the three pumps must be constantly in operation, continues to occur a high energy loss. Furthermore, a solution according to EP 0189164 is known, in which with increasing torque of the screw conveyor via control valves, the pressure supplied to the hydraulic motor of the screw auger by an amount by which the hydraulic motor of the centrifuge drum supplied Dreckflüssigkeitsmenge is reduced and vice versa. Also, this solution has the disadvantage that for the regulation of the differential speed between the centrifuge drum and the auger a high cost of hydraulic units is necessary and that a high energy consumption arrives due to the poor efficiency of hydraulic units. In DE-OS 3005658, the speed of the centrifuge drum and the screw conveyor and the differential speed are calculated by a computer, from which η from a control intervention on the speed of the screw conveyor takes place. The disadvantage of this solution is that for each product to be hurled a characteristic curve for the computer must be worked out to initiate a control intervention on the screw speed to correct the Differunzdrehzahl. According to US 3494542 a üentrifugenverfahren and a device are known, after which periodically the solid-liquid mixture is separated by the timing of the centrifuge is charged, wherein at the beginning of synchronization of drum and screw is present. By adding an eddy current brake for the discharge of settled solid a differential speed between the drum and screw is generated. This mode of operation, which is based on essentially split feed and delivery periods, is repeated in rapid succession, thereby providing a semi-continuous flow of the separated phases. The braking torque on the rotor depends directly on the coil current and the rotor speed, so that by applying a current to the coil, the braking torque can be varied. The disadvantage of this solution is that there is no continuous driving, thus low throughput. Furthermore, too high circuit complexity is required. Object of the invention The aim of the invention is to develop a circuit arrangement for regulating the differential speed between the centrifuge drum and screw conveyor of a solid bowl screw centrifuge, which is able to automatically regulate the differential rotational speed between the drum and screw, using simple and known technical means, depending on the screw torque.