SU1742194A1 - Cloth tension control device - Google Patents

Abstract

Use: for adjusting the tension of the web mainly in machines for slitting coiled materials. The essence of the invention: the device contains an unwinding roll 1, rollers 2,4,13 and 23, knife mechanism 3, electric motor 5, hydraulic pumps 6 and 9. throttle valve 7, hydraulic motor 8, filter 10, valves 11,12 and 16, lever suspension 14 , pneumatic cylinder 15, loop roller position sensor 17, electronic amplifier 18, electrohydraulic amplifier 19, pressure sensors 20 and 21, and clutch 22. 1 sludge.

Description

The invention relates to a device for processing a rolled web under tension and may find application in the pulp and paper industry, printing, chemical, textile, etc.

Known devices for creating tension, containing a hydraulic actuator to ensure unwinding of the coil with constant tension in acceleration, deceleration and constant speed, regardless of the level of unwinding speed and radius of the unwinding roll.

Closest to the invention is a device for regulating the tension of long material, comprising a roll unwinder hydraulic motor connected via hydraulic lines to a hydraulic pump, a loop roller kinematically connected to a loading mechanism including a pneumatic cylinder, drive rollers and a loop roller position controller with a sensor and electronic and electro-hydraulic amplifiers, while the hydraulic lines between the hydraulic motor and the hydraulic pump are made in the form of a closed circulation system fluid regulating washer pump provided with an electrohydraulic drive roller headlight loop connected to the input of an electrohydraulic actuator regulating washer pump.

However, in the known device, the washer allows you to adjust the performance of the hydraulic pump, but does not provide the possibility of reversing it, which is necessary to create the required moment (rotation or braking) on the unwinding roll to provide a given tension in the mode of acceleration or braking of the roll.

In addition, the rigid connection of the hydraulic pump with the pulling shafts in the presence of a rigid connection between the electric motor and the pulling shafts also eliminates the possibility of reversing the hydraulic pump.

Before starting the process of unwinding the blade, it is necessary to maintain its predetermined tension after refueling and to turn on the knife device for subsequent cutting. However, this device does not provide operation of the hydraulic motor associated with the unwinding roll, with the electric motor of the pulling shafts disconnected.

The purpose of the invention is to increase the efficiency of the device by adjusting the wear of the differential pressure on the hydraulic motor.

The drawing shows a schematic diagram of a device.

The device comprises an unwinding roll 1, a paper path consisting of guide rollers 2, a knife mechanism 3 and a mechanism of pulling rollers 4, which are a linear unwinding speed generator. The pulling rollers are connected to an electric motor 5 provided with a linear speed control system (not shown). The electric motor 5 is connected simultaneously with a variable displacement hydraulic pump 6. The load in the supply line of the hydraulic pump 6 is the input diagonal (PT) of the hydraulic bridge of the throttling valve 7, for example, based on the throttle valve type C with proportional electrical control. A hydraulic motor 8 is connected to the output diagonal of the hydraulic bridge (A-B), kinematically connected to the roll 1.

For cavitation-free operation of the hydraulic pump, an auxiliary auxiliary system is used, consisting of an additional hydraulic pump 9 of constant capacity, a filter 10 and a non-return valve 11. To protect the pressure line of the hydraulic pump 6 from overload, a safety valve 12 is used.

The looper roller 13 is covered by a canvas at a constant angle and is fixed on the swingarm linkage 14. The suspension arms of the looper roller are connected to the rod of the pneumatic cylinder 15, into the piston cavity of which compressed air flows under pressure, regulated by a throttling pneumatic valve 16 having manual or remote electrical control. A sensor 17 of the loop roller position is connected to the axis of rotation of the pendulum suspension 14, the sensor can be either potentiometric with an analog output signal or photoelectric with a pulse output signal. The output of the sensor 17 is connected to the input of the electronic amplifier 18, the output of the latter is connected to the input of the electro-hydraulic amplifier 19. The throttling valve 7 is equipped with two pressure sensors 20 and 21, which are integrated in the output hydraulic lines A and B to control the differential pressure of the working fluid at the inputs of the hydraulic motor 8. The outputs of the sensors 20 and 21 pressures are connected to the inputs of the amplifier 19. The control output signal of the amplifier 19 is supplied to the control valve 7. To turn the drive shafts on or off when the hydraulic pump is running serves as a coupling 22. The device also contains a roller 23.

The device operates as follows.

When you turn on the motor 5 and the coupling 22, the pulling rollers 4 provide material feed and unwinding the roll, while the required tension of the transported roll material provides the loop roller 13. In the static steady state, the loop roller 13 occupies a vertical position together with the pendulum suspension 14. The output signal of the position sensor 17 equal to zero. The output signal of the loop loop electronic position amplifier 18 is a reference input signal for the electro-hydraulic amplifier 19 controlling the control valve 7. At the same time, the differential pressure is set at the output of the control valve 7, which corresponds to a roll unwinding speed at which the pendulum suspension of the loop roller occupies a vertical position. As the roll is unwound, its diameter decreases, which leads to an increase in the web tension, while the loop roller 13 deviates from the equilibrium position. The output signal of the loop roller position sensor 17 causes a decrease in the pressure drop across the oil supply line to the hydraulic motor 8. As a result, the torque and roll rotation speed on the roll change so that the pendulum suspension 14 with the loop roller 13 returns to its original vertical position, and the output signal the loop roller position sensor 17 assumes a zero value.

The sensor 1 7 position of the loop roller 13 is an integrator of the deviation of the tension of the moving web from a given level. During the movement of the web, its tension is ensured due to the relative mismatch of the linear speeds of the drive of the pulling shafts and the roll in accordance with the expression at = efAv, where Δ is the deviation of the web tension from the reference;

EF is the tensile stiffness of the material web;

Δν

y — the relative mismatch of the drive speeds of the pulling shafts and the roll.

In dynamic modes, during acceleration or deceleration of the roll, a deviation of the position of the loop roller clockwise or counterclockwise causes a corresponding change in the pressure drop at the output of the control valve both in sign and size so that the corresponding change in the direction of rotation, torque, and unwinding speed leads to a return the loop roller to its original position .. In this case, the linear speed of rotation of the roll on the roll is equal to the speed of the pulling rollers, and the tension of the unwinding material with corresponds to a given pressure of compressed air in the pneumatic cylinder 15. The electronic amplifier 18 implements the proportional-integral-differential transformation law, has an astatic property, i.e. due to the integral component is able to maintain a constant level of the output signal at a zero value of the input signal from the sensor 17 of the position of the loop roller. When the input driving signal is zero, the output of the electrohydraulic amplifier 19 is set to a zero output signal, and the same pressure is set on the hydraulic lines A and B of the control valve 7, equal to half the supply pressure at the inlet. The pressure differential at the outputs of the control valve 7 is equal to zero. When changing the magnitude and polarity of the control electrical output signal of the amplifier 19, the pressure difference of the working fluid at the outputs A and B of the control valve 7 changes proportionally in magnitude and sign from zero to the magnitude of the supply pressure. In this case, the hydraulic motor 8 is able to change the direction of rotation, the transmitted moment and speed of rotation in the range of its technical characteristics.

The hydraulic motor control with the help of a throttling valve with proportional control and feedback on the differential pressure on the roll hydraulic motor provides reverse operation of the hydraulic motor and high dynamic parameters of the material tension control system when it is unwound from the roll on the roll, as well as the ability to maintain tension on the roll when disconnecting the electric motor from the pulling shafts, excluding breaks of the canvas and increasing the efficiency of regulating its tension.

Claims (1)

Claim A device for adjusting the web tension, mainly in machines for the longitudinal cutting of rolled materials, comprising a roll unwinder hydraulic motor connected via hydraulic lines to a hydraulic pump, a loop roller mechanically connected with a linkage suspension, a roller position adjuster including a pneumatic cylinder connected in series, a roller position sensor connected with an axis of rotation of the suspension, electronic and electro-hydraulic amplifiers, characterized in that, in order to increase the efficiency of work CTBA, it is provided with a throttling control valve mounted on the hydraulic lines and the associated electrohydraulic amplifier output, datchi5 kami pressure mounted on the line supplying hydraulic fluid to the hydraulic motor and associated electrohydraulic amplifier inputs.