Control System Of Water Jet Looms

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< p > > a href= "http://www.91se91.com/news/" > loom > /a > control system usually takes CPU as the control center, weaving, preparing, running, turning, stopping, positioning and braking, as well as all kinds of fault inspection (mainly including warp tension, Zuo Youjiao edge, waste wire before and after, fixed length and weft thread detection). After analysis and processing, it is controlled by executive elements.

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< p > PLC control system takes the PLC programmable controller as the control center, and sends the preceding instruction signals and detection signals to the input end of PLC. After the PLC is analyzed and processed, the execution instructions are issued to control them.

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< p > control system mainly includes loom pmission and braking, loom fault detection, weft detection, logic control, electronic weft filling, electronic let off, electronic take-up and so on.

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< p > (1) loom pmission < /p >

< p > water jet looms, because of their simple weft insertion system and high strength of warp materials, have higher speed and higher requirements for main drive motors: higher starting torque and reverse torque of fast braking, while considering frequent starting and striking current caused by frequent forward and reverse movement.

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< p > because of its unique working environment (large working environment humidity), it has high insulation and sealing performance for motor.

The motor of the water jet loom must have a higher starting torque to meet the initial weft beating force of the loom and avoid weaving weft defects.

In order to satisfy the fast braking of looms, the rotor of the motor must be able to withstand larger torque.

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< p > the main drive motor is internally equipped with temperature switches for overheating protection.

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< p > main drive motor must be regularly lubricated to ensure normal operation.

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< p > to ensure the normal start and operation of looms, the spindle heads of the main drive motors are generally tapered.

Different types of machines have different tapers.

When using or replacing pulley, ensure that the pulley has enough contact with the motor shaft.

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< p > to ensure enough starting torque and working torque of the loom, the main motor belt must have enough tension.

Usually, the belt tension is detected by direct tension tester.

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< p > to ensure good a href= "http://www.91se91.com/news/index_c.asp" > fabric > /a > quality, water jet looms must be precisely positioned and braking.

The brake of water jet looms includes the electromagnetic brake of the electromagnetic brake and the reverse braking of the main drive motor.

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< p > the water jet loom brake system must ensure that the beating axis is stopped within the range of 170 degrees 20 degrees, and it is guaranteed to stop at the first weft after the weft breaking instruction is issued.

The brake system consists of an electromagnetic brake, a power supply and a control loop.

As shown in Figure 3 - 38.

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< p > water jet looms generally adopt monolithic electromagnetic brake (3 - 39).

The moving piece (metal friction material) is composed of static film (the surface is non-metallic friction material, and the inner part is buried with coils).

The utility model has simple structure and convenient operation.

The electromagnetic brake is divided into two forms: single coil and double coil according to the type of coil.

The water jet looms produced by Shenyang Hongda Textile Machinery Company (Shenyang Textile Machinery Factory) and Toyota Corporation (formerly NISSAN company) use single coil electromagnetic brake; the water jet looms produced by Tianjin Tian Ju and Yin Chun company use double coil electromagnetic brake, that is, high voltage coil and low voltage coil.

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The brake torque of the electromagnetic brake used for loom is less than 160~350 P N m.

The higher the speed of the loom and the wider the width of the loom, the greater the required braking torque.

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< p > electromagnetic brake must be two parallel planes and the spacing is between 0.25 and 0.4 mm.

When using, avoid two stains to stain oily dirt.

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< p > loom use, check the brake clearance regularly and adjust it to ensure normal operation.

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< p > when the electromagnetic brake is used, the leads must not be grounded, so that the output power tube is not burned.

The wiring of ZW type water jet loom brake can not be reversed, and its polarity can not be changed.

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< p > (two) fault detection and self stopping device < /p >

< p > water jet looms have multiple fault detection and self stopping devices to ensure the loom's normal operation.

Its main functions are as follows: < /p >

< p > (1) left and right side side stop: install on the side of the side of the loom.

When the hank yarn is broken, the guide hook relies on spring force to make the process contact action stop.

Usually brush type process contacts or non-contact switches, such as reed switches, photoelectric switches, proximity switches and so on.

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< p > (2) over tension self stop of warp: installed on the left rear part of loom, controlled by loose arm.

When the warp tension is too high, stop instruction is issued.

The micro limit switch is usually used.

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< p > (3) the broken ends of the waste silk spool are installed on the right rear part of the loom and controlled by the guide hook.

When the twisted yarn is broken, the guide bar hooks to issue a stop order.

Guide hooks are usually used to process contacts.

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P > (4) waste silk self stop: installed in the front of the right side of the loom, the lever is controlled, when the waste wire is broken, the lever action, the related contact contact and the parking instruction are sent.

Holzer switches or process contacts are usually used.

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< p > (5) fixed length self stop: installed inside the loom meter, when the fabric reaches a predetermined length, the parking or dropping instructions are issued.

If a mechanical meter is used, a microswitch is used to send the message; when the electronic meter is used, it is sent directly.

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< p > (6) other self stop: besides the above fault detection, most of the water jet looms also have the following fault detection (not process self stop).

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< p > main motor and air pump motor internal temperature switch (motor overheating protection), when the motor overheating, automatic shutdown.

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< p > brake internal temperature switch (electromagnetic brake overheating protection).

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< p > (three) weft detection < /p >

The weft detection of water jet looms (< p > >) is commonly referred to as "weft detection device". There are mainly three forms: the latter two forms are widely used.

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< p > (1) mechanical weft detection device: its working principle is similar to that of a "chicken pecking rice" weft detector with shuttle looms, which is mainly used in Czech water looms by using its spring and lever technological contacts.

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< p > (2) touch finger type weft detector: its working principle is to use the high voltage direct current generated by the weft detection unit to supply the feeler of the weft feeler. When the contact finger is contacted with the water cut weft, the water and weft wire will connect the weft detection circuit to produce a signal with weft threads; if there is no weft, there is no electrical signal, that is, the output stop signal.

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< p > according to the installation and structure of the feeler type weft detector, it is divided into two types: the upper type weft insertion and the lower position weft insertion.

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< p > top mounted weft insertion is directly installed on the top of the reed, which can be easily installed, adjusted and replaced. Because of its split structure and partial replacement, the maintenance cost is small.

Its disadvantage is that it does not adapt to high speed operation, so it has been phased out in recent years.

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< p > the lower positioned weft is the integral structure, which is directly installed on the beating up axis, and the probe and the lead cable are sealed by engineering plastics.

Because it has no mechanical connection with reed, it has better rigidity and high reliability of weft detection.

In recent years, due to the application of photoelectric weft detection, the use range of downward setting weft is gradually narrowing.

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< p > (3) photoelectric type weft detector: its working principle is to change the level of photoelectric signal when weft filament is used to block the light source and detect the weft.

Usually, GaAs infrared light source and phototube are used to form photoelectric detection circuit. When weft is weft, the weft is injected to a predetermined position. When it enters the photoelectric detection area, the light source is blocked, so that there is "weft" signal in the detection circuit. If there is no weft wire and light source is not broken, there is a "weft free" signal in the detection circuit.

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The main features of the P photoelectric probe device are that it is suitable for wide variety of species, not affected by water quality and strong anti-interference ability.

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< p > photoelectric weft detection device consists of photoelectric sensor and lead, control unit and mounting bracket.

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< p > when installing the photoelectric weft detector, ensure that the bottom and the left and right sides do not collide with the reeds and reeds, and the upper part of the detection mouth is in the same plane with the warp threads.

To ensure that weft flying can accurately enter the photoelectric probe device.

The adjustment method is to adjust the hand wheel of the loom to 0 degrees, and observe whether the weft yarn of the weft is entered the detecting point of the photo detecting device.

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< p > the adjustment method of the front and rear position of the photoelectric type weft detector is to make the spacing between the weft line and the light detection point at 15 mm, and make the weft line enter the detection point of the photo detecting device at the hand wheel 310 to 340 degrees.

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< p > the adjustment of photoelectric weft detector should first adjust the weft insertion of the loom to the best condition and scissors adjust to the best condition.

To ensure that the scissors cut the weft yarn, keep 2~3 of them.

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< p > photoelectric probe device consists of probe and control unit.

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< p > probe consists of light guide < a href= "http://www.91se91.com" > fiber > /a > infrared photoemission tube, photoelectric tube and circuit. When loom works, weft goes into detection point. In this process, photoelectric signal is converted into electrical signal and sent to control unit.

The control unit processes and amplifies the weft detection signal to determine whether the weft insertion is correct, so that the corresponding weft signal is sent to the loom main control panel.

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< p > probe leads: power supply (positive), power supply (negative), signal.

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< p > control unit lead: +12V, weft output (F), synchronous signal input (FtIR) (PS), synchronous signal output (Ft or PS), stop signal output (STOP), power OV.

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