How to use pressure relay
1. When it is first used for safety protection, set the pressure relay at one end of the clamping hydraulic cylinder. After the hydraulic pump is started, first clamp the workpiece. At this time, the pressure in the right cavity of the clamping hydraulic cylinder rises. When the setting value of the relay is set, the pressure relay acts and sends out an electric signal to energize the 2YA, so the cutting hydraulic cylinder advances cutting. During processing, the normally open contact of the pressure relay micro switch is always closed. If the workpiece is not clamped, the pressure relay 2 is disconnected, so the 2YA is cut off, and the cutting hydraulic cylinder immediately stops feeding, so as to avoid accidents caused by the workpiece being cut without clamping.
2. In fact, when it is used to control the sequential action of the actuators, after the hydraulic pump is started, first the 2YA is energized, the left cavity of the hydraulic cylinder is filled with oil, and the piston is pushed to move to the right. When it hits the stopper (or deadlock), the system pressure rises, and the pressure relay sends out an electrical signal to energize the 1YA, and high-pressure oil enters the left cavity of the hydraulic cylinder, pushing the piston to move to the right. At this time, if the 3YA is also energized, the piston of the hydraulic cylinder quickly moves to the right; if the 3YA is powered off, the piston of the hydraulic cylinder moves slowly to the right, and its slow motion speed is adjusted by the throttle valve.
3. When used for hydraulic pump unloading again, the pressure relay does not control the hydraulic pump to stop rotating, but controls the two-position two-way solenoid valve to flow the pressure oil output by the hydraulic pump 5 back to the tank to unload.
4. When finally used for the opening and closing of the hydraulic pump, there are two hydraulic pumps, a high-pressure small flow pump and a low-pressure large flow pump. When the piston descends rapidly, the two pumps simultaneously output pressure oil. When the piston rod of the hydraulic cylinder starts to pressurize against the workpiece, the pressure relay will act under the action of the pressure oil, touch the micro switch, disconnect the normally closed contact, and stop the hydraulic pump. Slow down the speed of the hydraulic cylinder during the machining process while reducing power consumption.
Use skills of pressure relay
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First of all, the quality of the selected product has problems, which are mainly reflected in the following aspects:
1. The action is not sensitive, and there is no signal output when the pressure is reached. This is a manufacturing problem and there is no test when it leaves the factory.
2. Send a message before the pressure is reached. It is an assembly problem. The micro switch in the pressure relay is not installed properly.
3. The product is not durable, and the pressure relay will not operate after a few moments. The manufacturer had no conscience and used a poor micro switch.
4. Oil leakage. If the sealing ring is not selected, the processing is out of tolerance.
The points listed above are all supplier’s problems. If users have problems, the pressure relay will not work. Relays have been widely used in computer peripheral interface equipment, constant temperature systems, temperature adjustment, electric furnace heating control, motor control, CNC machinery, remote control systems, industrial automation equipment; signal lights, dimming, flashers, lighting stage lighting control systems; instruments Instruments, medical equipment, photocopiers, automatic washing machines, automatic fire fighting, security systems, as well as switching switches of power capacitors used as power factor compensation for power grids, etc., and are widely used in chemical, coal, and other occasions that require explosion-proof, moisture-proof and corrosion-proof .
Low-level errors:
1. No output signal: The small hole for pressure measurement is blocked by the raw material tape, and the assembler is not careful.
2. Inaccurate pressure measurement: The phenomenon is that the relay sends a signal before the pressure gauge indicates the pressure. In fact, the operating speed of the pressure relay will be faster than the pressure gauge, especially than the oil-filled shock-resistant pressure gauge. So maybe the pressure gauge has only reached 10M, and the pressure relay is already 20M.
Advanced errors:
1. The pressure relay is not sensitive and difficult to adjust: the pressure range is not selected correctly. Because the spring is not linear, the pressure relay is generally divided into pressure levels. It is best to choose the appropriate pressure level.
2. The pressure dropped, and the normally closed contact of the relay did not reclose. This is because the pressure relay has a backlash problem, which is related to the manufacturer's process level. It also has a lot to do with the structure of the pressure relay. Other imitations are more difficult to say. There is a qualitative leap in action sensitivity and stability. Especially in the low pressure section, that is, in the range of 0-50kgf/cm. The advantage of agility is obvious.