The heating system of the hollow blow molding machine storage head is divided into three parts: the first part is the temperature control instrument part; the second part is the contactor part; the third part is the heater part. It should be noted that there have been some changes in the heating system of large blow molding equipment produced in recent years. The temperature control module of the PLC is used instead of the temperature controller, the solid state relay is used instead of the contactor, and the heater part has not changed much. These technological advances or improvements provide convenience for the integration of the electronic control system, and can reduce the contacts and components of the electronic control system. With the advancement of electrical control technology, the integrated temperature electrical control system may completely replace the current temperature control system.
1.Maintenance and maintenance of temperature control instruments
Most of the temperature control instruments used for the temperature control of large storage heads are temperature control instruments that do not need to output a cooling circuit. During the use of the equipment, the following maintenance and repair work needs to be done:
1) Pay special attention to keeping the temperature control instrument clean, and use the downtime to clean the instrument.
2) Frequently check whether the wiring of the temperature control instrument is firm, to prevent the normal operation of the temperature control instrument due to loose wiring and contacts.
3) Pay attention to check whether the wiring of the temperature sensor is firm.
4) In hot climate conditions, pay attention to observe the temperature of the environment where the temperature control instrument is used to ensure that the ambient temperature of the instrument is within the normal operating temperature range. When the ambient temperature is too high, effective cooling measures need to be taken.
5) In humid climate conditions, if the equipment is in a shutdown state, it is necessary to regularly supply power to the temperature control instrument to prevent the instrument from being damaged due to moisture. When the equipment is stopped for a long time, it must be carefully inspected, after confirming that it is correct, first supply power for 4 ~ 6h before use, and then let it go to work.
6) Replace the temperature control instruments and temperature sensors that have failed. When replacing, pay special attention to whether the model, voltage and temperature control range of the temperature control instrument are consistent, and ensure that the wiring is correct.
2.Maintenance and maintenance of contactors
The working state of the contactor of the heating system is slightly different from that of the motor contactor. Due to the characteristics of temperature control, the contactor of the heating system has been in the frequent alternating work of being turned on and off for a long time. The contactor and the coil of the contactor are in a high-load working state. Damaged by the constant impact of current.
In daily use, you need to pay attention to the following maintenance and maintenance work:
1) Pay attention to keep the contactor clean, and use downtime for cleaning.
2) Frequently check whether the contactor protection circuit works normally. If any problem is found, replace or repair it in time.
3) Regularly check whether the fasteners are loose, especially the connecting parts of wires and conductors, to prevent loose contact and heat.
4) Regularly check whether the positions of the dynamic and static contacts are aligned, and whether the three phases are closed at the same time. If there is a problem, adjust the contact spring.
5) Regularly check the wear of the contacts. The wear depth must not exceed 1mm.
6) When the contacts are severely burnt, and they are broken during welding, they must be replaced in time. However, when it is slightly burned, it generally does not affect its use.
7) Sandpaper is not allowed when cleaning contacts. A plastic file should be used.
8) Periodically measure the insulation resistance between phases, and the resistance value should not be less than 10MΩ.
9) Regularly check whether the action of the auxiliary contact is flexible. The stroke of the contact should conform to the specified value. Check whether the contact is loose or fall off. When a problem is found, it should be repaired or replaced in time.
10) Do regular maintenance of the core part. Pay attention to cleaning the dust, especially between the moving parts and the contact surface of the iron core. Carefully check the tightness of the iron core. Loose cores will cause increased operating noise. When the core short-circuit ring comes off or breaks, repair it in time.
11) Do regular maintenance of the electromagnetic coil. Measure the coil insulation resistance, check the coil insulation for discoloration and aging, and the surface temperature of the coil should not exceed 65 ℃; carefully check the connection of the coil leads, and repair it in time if there is welding or burning.
12) Do some maintenance of the arc extinguishing cover. Check whether the arc extinguishing cover is damaged, and whether the position of the arc extinguishing cover is loosened or changed; remove metal particles and debris in the gap of the arc extinguishing cover.
13) If the contactor of the heating system has failed, it should be replaced in time. When replacing, pay attention to the main parameters such as model, power, coil voltage, etc., which must meet the technical requirements of the equipment, and ensure that the wiring is correct and the contactor is fixed and reliable.
3.Maintenance and maintenance of heater
The working state of the heater directly affects the normal operation of the storage head, but also affects the quality and output of the product. The main points of attention during use are as follows:
1) Regularly check whether the wiring at the connection point is firm and reliable, and whether the protection of the safety porcelain cap at the connection point is normal.
2) Regularly check whether the fixing device of the heater is reliable. If the fixing device does not have an automatic locking structure, a device with a spring should be installed to ensure that the heater fits tightly with the outer ring of the barrel.
3) Regularly check the insulation of the heater. If the insulation is found abnormal, the heater should be replaced in time.
4) Regularly check whether the heat insulation part of the heater is effective and reliable. If there is any abnormality, repair or replace the heat insulation part.
5) Frequently check whether the temperature sensor wiring is reliable, and repair or replace it in time when abnormal.
6) When replacing the heater, pay attention to the matching of voltage and heating power. In order to make the heater durable, the power per unit area should not be too large when selecting the heater, and it must meet the technical requirements of the equipment.
7) When replacing the power cord of the heater, high temperature resistant insulated wires need to be selected to prevent unsafe accidents.