Performance Assessment and Maintenance of Vacuum Brazing Furnace

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1.  Performance Test of Vacuum Brazing Furnace

The tested vacuum brazing furnace should be prepared and put into operation in accordance with the technical specification, relevant technical standards and relevant safety regulations. Before the test, the electrical wiring and switch system must be checked, and all necessary safety measures must be taken. The test must be carried out under normal working conditions in the vacuum brazing furnace after fully baking and degassing and the vacuum brazing furnace:

Measurement of the ultimate vacuum degree In the cold state of the empty furnace, use the vacuum system matching the body of the vacuum brazing furnace to test. The furnace of the vacuum brazing furnace should be able to reach the ultimate vacuum value specified in the technical documents.

Measurement of empty furnace evacuation time: From the time when the initial pressure in the furnace (generally the atmospheric state) starts the vacuum pump to start pumping, to the time when the vacuum degree in the vacuum brazing furnace reaches the vacuum degree specified in the technical documents, it is the empty furnace. Take time. In the test, the warm-up time of the oil diffusion pump and the oil booster pump is not included in the empty furnace evacuation time.

Measurement of pressure rise rate: After the oven is completed, in a clean, cold, and no-load state, the vacuum degree is measured from P1 to P2 in the time period from t1 to t2, and the pressure rise rate = P2-P1/t2-t1, P The unit of is Pa, and the unit of t is hour, so the unit of pressure rise rate is Pa/h. The standard is 0.67Pa/h.

Measurement of working vacuum degree In the vacuum furnace operation test, the test is carried out according to the working temperature (assessment temperature) specified in the technical documents, and the specified vacuum degree value should be reached.

The test of the heating time can be carried out after the vacuum brazing furnace is empty and the vacuum in the furnace has reached the working vacuum. During the test, adjust the input power of the furnace to make it equal to the constant power (a deviation of ±10% is allowed); the time from turning on the power supply to reaching the assessment temperature is the heating time of the vacuum furnace.

The furnace temperature uniformity test is performed when the empty furnace is in the verification state of the assessment temperature and the vacuum degree is at the working vacuum degree. A total of 5 measurements are taken, and the arithmetic average of the maximum temperature difference of the 5 times is taken, and the temperature is measured. The area, the number and location of temperature measurement points should be in accordance with the provisions of the technical documents.

2. Repair and Maintenance of Vacuum Brazing Furnace

After stopping the furnace, the furnace must be kept in a vacuum state below 6.65X1O4Pa.

When the furnace is dusty or dirty, wipe it with a stretch cloth soaked in ethanol or gasoline and let it dry.

When disassembling and assembling the sealing structure, vacuum system and other parts on the furnace body of the vacuum brazing furnace, clean it with a second grid (or gasoline, and dry it with vacuum grease before assembly.

The outer surface of the furnace should be wiped frequently to keep it clean.

Workpieces, baskets, and workpiece carts must be cleaned and dried before entering the furnace to prevent moisture and dirt from entering the furnace.

When all the transmission parts are found to be stuck, inaccurate in the limit and control failure, they should be eliminated immediately, and do not force the operation to avoid damage to the parts.

Mechanical transmission parts are regularly refueled or changed according to general equipment requirements.

Accessories such as vacuum pumps, valves, measuring instruments, thermal instruments and electrical components should be used, repaired and maintained in accordance with the product technical specifications.

Maintenance operations should be carried out under power outages. When performing maintenance work under power-on conditions, the absolute safety of the operators, maintenance personnel, and equipment must be ensured.

Common Faults and Troubleshooting Methods of Vacuum Brazing Furnace:

 

Vacuum Pump
Malfunction	Cause	Method
Low Vacuum	Pump oil viscosity is too low	Change to the specified grade of oil
	Insufficient pump oil	Add fuel
	Pump oil is not clean	Replace with new oil
	Air leakage at the output end of the shaft	Replace shaft end oil seal
	Damaged exhaust valve	Update new valve
	Leaf spring break	Replace with new spring
Pump is Stuck in Operation	The sundries are pumped into the oil	Disassemble the pump for repair
	Working under high pressure for a long time causes the pump to overheat, the parts expand, and the gap is too small	Don´t work for a long time under high pressure, strengthen cooling
Pump is Running Abnormally Noisy	Pump overload	Disassemble the pump for repair
	Partial wear of the internal parts of the pump cavity	It is not suitable to work under high pressure for a long time, strengthen the cooling of the pump
Difficulty Starting the Pump	The pump cavity is filled with oil	Inflatable in the case
	Motor circuit shorted	Troubleshoot the circuit
	The motor is faulty	Repair the motor
	Transmission belt is too loose	Transmission belt tightness
	There is a foreign body in the pump cavity	Replacement and repair