SU1368496A1 - Device for controlling centrifugal compressor - Google Patents

Abstract

The invention allows to increase the reliability and efficiency in off-design modes. The total pressure nozzles are made in the form of combs and placed on the back and trough side of one of the blades 3. The regulator is made extreme to find the minimum pressure difference from the back and trough. When the flow rate of the pumped medium changes, the signal from sensors 8 and 9 will be fed to the extreme a regulator for finding the minimum absolute value of the differential pressure. As a result, the direction of rotation of the electric motor will change, and the blades will be set to a position that provides maximum efficiency. 2 Il.

Description

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The invention relates to the control of centrifugal compressors mainly to compressors with rotary diffuser vanes.

I The purpose of the invention is to boost on ™.

| Reliability and profitability of non-calculation

1 modes.

I FIG. 1 shows a device diagram for finding the minimum absolute value of the pressure difference 1P. If aP O, which corresponds to an increase in the flow rate of the pumped medium, then an electrical signal from sensor 9 is fed to amplifier 10 and from there to a differentiating chain with a time constant RC (R is

control of centrifugal compress-JQ resistance 11; C is the capacitor value; in fig. 2 is a section A-A in FIG. one.

The control unit of the centrifugal compressor with rotary vanes of the diffuser contains gears 1 mounted on the axles 2 of the rotations of the blades 3 and interconnected by a gear ring 4, two nozzles 5 and 6 of full pressure, the channels of which are connected to the controller acting on the drive 7 nozzles 5 and 6 of total pressure are made in the form of combs and are placed on the back and trough side of one of the blades 3, the regulator is made extreme to find the minimum pressure difference L from the back and trough of the blades. Nozzles 5 and 6 are equipped with sensors 8 and 9, which convert the pressure difference dP from the side of the wall and the trough of the blades into an electrical signal. The controller contains an amplifier 10, a circuit with a resistance of 11 and a capacitance of 12, two-way polarized relays 13 and 14, a tachogenerator 15, a coil 16 that changes the direction of the current B of the tachogenerator circuit 15 and directs its rotation. Contacts 17 and 18; connected respectively to relay 13 and; 14. In addition, the sensor 8 is connected i through an amplifier 10 with a coil 19, I switching the current in the windings of the electric motor and changing its direction

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; rotation The tachogenerator 15 is equipped with clamps 20. The actuator 7 has a scraper

Mr. Nu 21.

The device works as follows.

When switching to an uncalculated mode of operation, a change in the flow angle on the diffuser vanes occurs, which leads to an increase in the absolute value of the differential pressure differential pressure from the back and trough of the vanes. The total pressure sensed by the nozzles 5 and 6 is converted by sensors 8 and 9 into an electrical signal that is applied to the extreme mode.

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capacitor 12), Voltage U. |. controls the on-off relay 13, the power supply circuit of which is controlled by the on-off polarized relay 14. The latter is powered by the voltage generated by the tachogenerator 15. When the device operates on the left branch of the U. f characteristic (), the system tends to equilibrium, while the voltage in the circuit drops and capacitor 12 is discharged. The potential of point a is less than point b. After passing through the extremum, the voltage on the circuit begins to rise, the capacitor 12 is charged, and the potential of point a becomes greater than point b. The contact 18 of the polarized relay flips and changes the direction of rotation of the electric motor, the latter causing the circuit voltage to drop, the discharge of capacitor 12 and the polarity change on the resistance 11. The potential at point a again becomes lower than at point b. However, simultaneously with a change in polarity, for example -. The voltage on the resistor 11 changes the polarity of the terminals 20 of the tachogenerator 15 and the contacts 17 of the relay are moved upwards. Therefore, the engine is not reversed, but continues to work, increasing the angle oh. After the passage of a minimum, the voltage in the circuit begins to increase. The capacitor is charged and the potential at point b becomes lower than at point a, and the relay contacts are moved down, the reversing motor 7, When

This blade is located in the zone providing the maximum CCT "

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At 4P O, the pressure difference converts the sensor 8 into an electrical signal. After amplification, the electrical signal is fed to the regulator and the coddle 19. This causes a change in the direction of rotation of the electric motor 7, which increases the angle 0 / J with P 0 and at LR; Oh reduces him Otherwise further work

The device is implemented in a similar way.

Claims (1)

Invention Formula The control unit of the centrifugal compressor with rotary vanes of the diffuser, which contains gears mounted on the axes of the blades rotation and interconnected by a toothed crown, two nozzles of total pressure. OmbiS the channels of which are connected to the controller acting on the drive, characterized in that, in order to increase reliability and economy in off-design modes, the total pressure nozzles are made in the form of combs and placed on the back and trough side of one of the blades, the controller is made extreme to search for a minimum of the pressure difference from the back and the blade vanes. FIG. 2