Selection of the installation site of the rapid temperature change test chamber:
The distance from the adjacent wall can smoothly give full play to the role and characteristics of the environmental test chamber. The long-term temperature of 15 ~ 45 °C and the relative environmental humidity exceeding 86% should be selected. site.
The working temperature of the installation site must not change significantly.
It should be installed on a leveling surface (use a level to determine the level on the road during installation).
It should be installed in a site without sun exposure.
It should be installed in a site with excellent natural ventilation.
It should be installed in areas where flammable materials, explosive products and high-temperature heat sources are eliminated.
It should be installed in a site with less dust.
Install it as close as possible to the switching power supply of the power supply system.
High and low temperature test chamber may encounter a variety of problems in the process of use, the following is a summary of potential faults and their causes from different perspectives:
1. Core system failure
Temperature out of control
Reason: PID control parameters are out of balance, ambient temperature exceeds the design range of the equipment, multi-zone temperature interference.
Case: In a special environment workshop, the external high temperature causes the refrigeration system to overload, resulting in temperature drift.
Humidity is abnormal
Reason: poor water quality of humidification leads to scaling and nozzle blockage, failure of ultrasonic humidifier piezoelectric sheet, and incomplete regeneration of dehumidification desiccant.
Special phenomenon: reverse condensation occurs during high humidity test, resulting in the actual humidity in the box being lower than the set value.
2. Mechanical and structural problems
Air flow is disorganized
Performance: There is a temperature gradient of more than 3℃ in the sample area.
Root cause: the customized sample rack changed the original design air duct and the accumulation of dirt on the centrifugal fan blade led to the destruction of dynamic balance.
sealing failure
New failure: the magnetic force of electromagnetic sealing door decreases at low temperature, and the silicone sealing strip becomes brittle and cracks after-70℃.
3. Electrical and control system
Intelligent control failure
Software level: After firmware upgrade, the temperature dead zone setting error occurs and the historical data overflow causes the program to crash.
Hardware level: SSR solid state relay breakdown causes continuous heating and bus communication is subjected to inverter electromagnetic interference.
Security protection vulnerabilities
Hidden dangers: the synchronous failure of the triple temperature protection relay and the false alarm caused by the expiration of the refrigerant detector calibration.
4. Challenges of special working conditions
Specific temperature shock
Problem: -40℃ to +150℃ rapid conversion of the evaporator weld stress cracking, thermal expansion coefficient difference resulting in the failure of the observation window seal.
Long-term operation attenuation
Performance degradation: after 2000 hours of continuous operation, the compressor valve plate wear leads to a decrease of 15% in refrigeration capacity and drift of ceramic heating tube resistance value.
5. Environmental and maintenance impact
Infrastructure adaptation
Case: The power oscillation of PTC heater caused by the fluctuation of power supply voltage and the water hammer effect of cooling water system damaged the plate heat exchanger.
Preventive maintenance blind spots
Lesson: Ignoring the positive pressure of the box leads to water entering the bearing chamber and biofilm growth and blockage in the condensate discharge pipe.
6. Pain points of emerging technologies
New refrigerant application
Challenges: system oil compatibility problems after R448A replaces R404A, and high pressure sealing problems of subcritical CO₂ refrigeration systems.
IoT integration risks
Fault: The remote control protocol is maliciously attacked, resulting in program tampering and cloud storage failure, resulting in the loss of test evidence chain.
Strategy recommendations
Intelligent diagnosis: configure vibration analyzer to predict the failure of compressor bearing, and use infrared thermal imager to scan the electrical connection points regularly.
Reliability design: key components such as evaporator are made of SUS316L stainless steel to improve corrosion resistance, and redundant temperature control modules are added to the control system.
Maintenance innovation: implement a dynamic maintenance plan based on operating hours, and establish an annual refrigerant purity testing system。
The solutions to these problems need to be analyzed in combination with the specific model of the equipment, the use environment and the maintenance history. It is recommended to establish a collaborative maintenance mechanism including the OEM of the equipment, third-party testing institutions and user technical teams. For key test items, it is recommended to configure a dual-machine hot standby system to ensure the continuity of testing.
(1) Equipment installation and commissioning
On-site service: technical personnel will deliver the goods free of charge and complete the mechanical assembly, electrical wiring and debugging. The debugging parameters shall meet the temperature and humidity, salt spray deposition amount and other indicators in the customer's technical agreement.
Acceptance criteria: provide a third-party measurement report, and unqualified equipment shall be returned or replaced directly. For example, the rain test box shall pass 100% acceptance.
(2) Customer training system
Operation training: covers equipment start and stop, program setting and daily maintenance, customized for different user scenarios such as quality inspection institutions and automobile enterprises.
Deep maintenance training: including fault diagnosis (such as troubleshooting of humidity system in high and low temperature and humidity test chamber) and spare parts replacement to improve customers' independent maintenance ability.
(3) Technical support and response
Instant response: respond to repair demand within 15 minutes, and solve routine faults within 48 hours (negotiate with remote areas).
Remote diagnosis: through video guidance or remote access software, quickly locate the problem (such as abnormal dust concentration in the sand test chamber).
(4) Spare parts supply and maintenance
Make spare parts plan, give priority to the supply of wear and tear parts from cooperative units (such as China Railway Inspection and Certification Center, China Electronics Technology Group), and reduce downtime.
Non-manual damage is free of charge during the warranty period, and paid services are provided after the warranty period with transparent charges.
1. Dust adhering to the condenser can cause the high-pressure switch of the compressor to trip and issue false alarms. Therefore, dust attached to the cooling grid of the condenser can be removed with a vacuum cleaner every month, or by using a hard-bristled brush after turning on the machine, or by blowing it off with a high-pressure air nozzle.2. The area around the machine and the ground at the bottom should be kept clean at all times to prevent a large amount of dust from being sucked into the unit or reducing equipment performance and causing accidents.3. When opening or closing the door or taking samples from the test chamber, do not touch the sealing strip on the door.4. The core of the constant temperature and humidity test chamber - the refrigeration system should be inspected once a year. Check for leaks in the copper tubes and at each joint and interface. If there are any, inform the manufacturer.5. The humidifier and water tank should be cleaned frequently to avoid scaling and affecting steam emission. Clean them after each test. Timely descaling helps extend the lifespan of the humidification tube and ensures smooth water flow. When cleaning, use a copper brush and then rinse with water.6. The distribution room should be cleaned and inspected more than once a year. Loose nodes can put the entire equipment in a dangerous working state, burn out components, cause fires, alarms, and endanger lives.7. The dry and wet bulb wicks should be checked frequently. Replace them promptly if they become hard or dirty. It is recommended to replace them every three months.8. Inspection and maintenance of the water circuit. The water pipes in the water circuit are prone to clogging and leakage. Regularly check for leaks or blockages. If found, remove them promptly or notify the manufacturer.
1. El condensador (o radiador) de la unidad de refrigeración en el cámara de prueba de choque de frío y calor Debe recibir mantenimiento regular para garantizar su limpieza. El polvo adherido al condensador puede provocar la activación del presostato de alta presión del compresor, lo que puede provocar falsas alarmas. El condensador debe limpiarse mensualmente con una aspiradora para eliminar el polvo de la malla de refrigeración. Después de encender la máquina, utilice un cepillo de cerdas duras para limpiarlo o sople el polvo con una boquilla de aire a alta presión.2. Al abrir o cerrar la puerta o sacar el objeto de prueba del horno, no deje que el objeto toque el borde de goma de la puerta para evitar que este se dañe y acorte su vida útil.3. Mantenga el suelo alrededor y debajo del fuselaje limpio en todo momento para evitar accidentes y degradación del rendimiento causados por grandes cantidades de polvo succionado por la unidad.4. El sistema de congelación de la cámara de pruebas de choque de frío y calor es el núcleo de esta máquina. Inspeccione cada seis meses todos los tubos de cobre para detectar fugas y presencia de nieve, así como todas las boquillas y juntas de soldadura. Si detecta una fuga de aceite, informe a la empresa o trátelo directamente.5. El contacto de alta corriente del panel de distribución debe limpiarse y repararse al menos una vez al año en la sala de distribución. Si se afloja, el equipo funcionará de forma peligrosa. En el mejor de los casos, quemará los componentes y, en el peor, provocará incendios, alarmas y lesiones personales. Al limpiar, utilice una aspiradora para eliminar el polvo de la habitación.6. No ajuste a la ligera el valor de ajuste de los dos protectores de sobretemperatura en la caja de distribución de energía de la cámara de prueba de choque de frío y calor. Este valor viene ajustado de fábrica. Este interruptor de protección protege el tubo calefactor contra quemaduras por vacío y la activación de la alarma. El punto de ajuste es de 20 °C a 30 °C.7. Cámara de prueba de choque frío y caliente Cuando se toma el producto de prueba cuando llega el momento, debe estar apagado y el personal debe usar guantes secos, antielectricidad y resistentes a la temperatura para tomar y colocar el producto.8. Limpie y mantenga el interior y el exterior de la cámara de pruebas de choque térmico y frío. 9. Antes de operar la cámara de pruebas de choque térmico y frío, elimine cualquier impureza interna. 10. La sala de distribución eléctrica debe limpiarse al menos una vez al año. Para la limpieza, utilice una aspiradora para eliminar el polvo. El exterior de la cámara debe limpiarse al menos una vez al año con agua jabonosa.
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