DD283488A7 - METHOD AND ARRANGEMENT FOR CONTROLLING SCREW PRESSES, EXTRUDERS & EXPANDERS - Google Patents

Abstract

The invention can be used in the operation of aggregates in which a material to be pressed is moved within a storage basket by means of a worm shaft. Preferred field of application is the food industry. The aim of the invention is to utilize the aggregates as high as possible, to ensure an optimal degree of filling of the unit and to protect the screws against excessive wear. The object of the invention is to provide a method and an arrangement for the control of screw presses, extruders, expanders and other units with a worm shaft, in which the presy pressure is adjustable by regulating the product supply. The object is achieved by means of a suitable arrangement for measuring the current consumption of the worm drive and for processing these tare values in a computer unit and for corresponding control of the product supply by controlling the speed of the tamping and dosing screw. Fig. 1 {screw shaft; Preszgut; Screw press; extruder; Expander; Fuellungsgrad; Preszdruck; Current consumption; Screw drive; Number of revolutions; dosing screw}

Description

For this 2 pages drawings

Field of application of the invention

The invention can be used in the operation of machines in which a pressed material is moved within a Preßkorbes by a worm shaft. Preferred field of application is the food industry. Thus, the invention of screw presses for the production of oil from predominantly oil-rich seeds or even in the crushing of meat in a meat grinder or special presses in fish processing or in the extrusion of legumes or in expanders for the preparation of low-oil seeds for direct extraction or the Schilfer oil-rich seeds for subsequent extraction and finally in equipment for granulation of vegetable ingredients, such as in the production of pellets in the feed industry, are used.

Characteristic of the known state of the art

Methods and apparatus for controlling screw presses, extruders, expanders, and other scroll-type assemblies are known.

The pressure to be applied during pressing to the material to be pressed depends essentially on the screw geometry, the degree of filling of the screw and the type of closure of the press. This closure consists in the meat grinders, extruders, expanders and granulators from a perforated disc or a die. Of the opening widths and their Durchlaßfähigkeiten the pressure profile in the interior of the respective units depends essentially.

Another possibility of influencing the pressing pressure is a change in the rotational speed of the main screw of the respective unit.

Solutions for the control of screw presses, extruders and expanders depending on adjusting pressure profile in the screw chamber are not known.

Object of the invention

The object of the invention is to provide a method and an arrangement for controlling screw presses, extruders and expanders as well as other machines in which a pressed material is moved within a screw chamber by means of a worm shaft, with which the machines are protected against excessive wear. At the same time, the operator of such machines should be enabled. To be able to make statements about the wear of sieve drums, cutting knives, worm shafts, rods or other determinant components or subassemblies.

It is also an object of the invention that the throughput of these machines should be increased and that the yield should be increased.

Explanation of the essence of the invention

The object of the invention is to provide a method and an arrangement for controlling screw presses, extruders and expanders and other machines in which by a screw shaft a pressed material is moved within a screw chamber, with which the pressing pressure by the main screw on the Preßgut acts, can be optimally designed for the respective process engineering task.

According to the invention the object is achieved in that the current consumption of the motor of the main worm is continuously measured, this determined value of the motor current is compared with a predetermined target value of the motor current and according to the determined difference between the measured value and the predetermined value of the motor current, the rotational speed of the metering screw the screw press or the extruder or expander or the other machines mentioned is regulated.

The arrangement for carrying out this method is characterized in that the motor of the main screw is connected to a measuring device for measuring the current consumption of the motor and that this meter is further connected to a computer unit and this computer unit with a voltage regulator, the motor of the dosing of the Screw press or the extruder or expander or the other machines mentioned is associated.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. Show it:

Fig. 1: schematic representation of the arrangement

Fig. 2: Dependence of the residual oil content in rapeseed pressing with a screw press type HSP 26 from the motor current of the main worm

In Figure 1, the arrangement for controlling a screw press is shown schematically. In this case, the motor 1 of the main worm is connected to a measuring device 2 for detecting the current absorbed by the motor 1. The meter 2 further has a connection to a computer unit 3. The computer unit 3 is also connected to the motor 5 of the metering screw 6 via a voltage regulator 4.

In the experiment, the screw press was fed via the metering screw 6 conditioned rapeseed with an oil content of 41.3%, a humidity of 6.1% and an inlet temperature of about 87 ⁰ C.

The speed of the main screw was η = 50min ~ \

With the measuring device 2, the motor current of the motor 1 was determined and transmitted to the computer unit 3 after conversion into an input signal. By the computer unit 3, the determined actual value of the motor current was compared with the predetermined target value.

According to the difference between the actual and desired value of the motor current, the rotational speed of the metering screw 6 was regulated via the voltage regulator 4 of the motor 5. In the experiment, a thyristor control was used as voltage regulator 4. In the experiment, the predetermined setpoint value of the motor current was 150 A. This value was determined as the optimum for the expected throughput of the screw press and the residual oil content in preliminary tests.

FIG. 2 shows the motor current of the main worm as a function of the residual oil content.

When using the solution according to the invention, the following results occur:

- Possibility of regulating the process for constant residual oil content,

- Reduction of energy consumption by 15%, ·

- high availability of the plant,

- Plant operation of central control room with several screw presses,

- increase plant safety,

- Fast display of malfunctions and thus possible rapid introduction of measures in case of limit violations, and ultimately the solution guarantees a consistent product quality.

Claims (2)

T. Method of controlling screw extruders, extruders and expanders and other machines in which a pressed material is moved within a screw chamber by a worm shaft, characterized in that the current consumption of the motor of the main screw is continuously measured, this determined value of the motor current with a predetermined Setpoint value of the motor current is compared and according to the determined difference between the measured value and the predetermined value of the motor current, the rotational speed of the metering screw of the screw press or the extruder or expander, or the other machines mentioned is regulated. 2. Arrangement for controlling screw presses, extruders and expanders and other machines in which a pressed material is moved within a screw chamber by a worm shaft, characterized in that the main screw driving motor (1) with a measuring device (2) for measuring the power consumption the motor (1) is connected and this measuring device (2) is further connected to a computer unit (3) and this computer unit (3) in turn with a voltage regulator (4), the motor (5) of the dosing screw (6) of the screw press or is associated with the extruder or expander or the other mentioned machines.