CB/T 3642-1994 Technical requirements for repair of marine boiler control systems CB/T3642-1994 standard download decompression password: www.bzxz.net

Shipbuilding Industry Standard of the People's Republic of China
CBT3636~3642-94
Technical Standard for Repair of Marine Boilers
Issued on August 22, 1994
China State Shipbuilding Corporation
Implemented on May 1, 1995
Shipbuilding Industry Standard of the People's Republic of China
Technical Requirements for Repair of Marine Boiler Control System B/T3642-94
Classification Number R32.
Subject Content and Scope of Application
This standard specifies the technical requirements for the inspection, repair, commissioning and acceptance of boiler water level control system and combustion control system. This standard applies to marine boilers with a working pressure not exceeding 1.6MPa and saturated steam.
2 General Requirements
2.1 The factory shall conduct the inspection of the automatic control system before repair together with the shipowner (and the ship inspection if necessary) according to the repair items proposed by the shipowner. After the inspection, the Guangzhou party shall propose the repair scope and acceptance outline approved by the shipowner. 2.2 The repaired control system shall be adjusted when the feed water pump, fuel pump, boiler fan and other equipment are in normal condition. After the factory commissions and passes the inspection, it shall be handed over to the shipowner together with the inspection department in accordance with the requirements of the acceptance outline. 3 Water level control system
Approved by China State Shipbuilding Corporation on August 22, 1994, implemented on May 1, 1995 43
CB/T 3642-94
Inspect whether there are debris and dirt on the surface of the water level sensor; whether the buoy is broken, and whether its linkage switch mechanism is flexible; whether the electrical components related to water level control in the control box and the connected wires are in good condition. 3.2 Repair
The dirt and debris on the surface of the sensor and the buoy linkage switch mechanism should be cleaned and the mechanism should be flexible.
Broken floats, water level sensors with no signal or weak signal must be replaced. The damaged components and circuits in the control box should be replaced. 3.3
The repaired water level control system must work accurately and reliably. The sensor should be able to stop the water supply pump when the boiler water level rises to the specified value; when the water level drops to the specified value, the water supply pump should be able to supply water; when the water level continues to drop to the specified limit value, the control system will sound and light alarms. The positions displayed on the water level gauge for the three actions of water supply, water cut-off and limit low water level adjustment of the water pump should be consistent with the original boiler requirements. If there is no original data, the adjustment can be carried out according to the requirements of the following figure.
Note: Normal standard value
CB/T3642-94
The relative position of the water supply pump to the water cut-off on the water level gauge is 75~120mm and must be located in the middle area of ​​the boiler water level gauge; the alarm point on the water level gauge is 25mm away from the lowest water level display position.
3.4 ​​Acceptance
3.4.1 When the boiler water level is lower than or higher than the specified normal water level, the effectiveness test of the automatic water supply or water cut-off of the water supply pump shall be conducted at least twice. 3.4.2 When the boiler water level drops to the specified limit value, the shutdown and alarm effectiveness test shall be conducted at least twice.
3.4.3 The mutual conversion effectiveness test of the boiler water level automatic control and manual operation shall be conducted at least once.
Combustion control system
4.1.1 Check whether the ignition transformer, high-voltage cable and electrode rod are in good condition and whether the electric sparks generated by them can ignite normally. 4.1.2
. Check whether the photoresistor is clean, measure its photosensitivity, and determine whether it is invalid.
Measure whether the atomization quality of the nozzle is good under the rated oil pressure. 4.1.4. Check whether the air-oil ratio mechanism is flexible and whether the air-oil volume is matched. Under the action of the pressure regulator, whether the action of the electric proportional operator meets the control requirements.
4.1.5 Check whether the opening and closing actions of the solenoid valve are correct, whether there are abnormal phenomena such as coil heating and magnetic core shaking in the working state, and whether the oil circuit is blocked and leaking. bZxz.net
4.1.6 Simulate and measure whether the pressure regulator and temperature regulator can normally send out the required signals.
CB/T3642-94
4.1.7 Check the control box according to the following requirements:
a. Perform routine electrical inspection to see if there are any obvious faults or damages; b. According to the problems encountered by the shipowner during use, focus on checking the relevant circuits and devices:
C. If necessary, check whether the working condition of the circuits and devices in the control box is good through simulation measurement;
d. Special electronic devices in the control box (such as electronic sequence controller, programmable controller, etc.). Check according to the product manual. 4.2 Repair
4.2.1 Damaged ignition transformers or electrode rods should be replaced, and loose or damaged wires should be tightened or replaced.
4.2.2 Unclean photoresistors should be cleaned, and failed or damaged photoresistors should be replaced, and they should be in good condition after being connected to the circuit. 4.2.3 The atomizing sheet of the nozzle with poor atomization quality should be mechanically trimmed (mesh, grind) or replaced as a whole.
4.2.4 In the disassembled air-oil ratio mechanism, the seriously defective parts and the electric proportional operator that does not meet the control requirements or is damaged should be replaced. The repaired air-oil ratio mechanism should be checked under the action of the pressure regulator, and the electric proportional operator and its driven mechanism should be flexible and reliable. 4.2.5
The solenoid valve that fails to operate must be disassembled and repaired, and replaced if necessary. 4.2.6
The pressure regulator and temperature regulator with no signal or weak signal should be replaced. 4.2.7
The damaged related components and circuits in the control box should be replaced. 4.3
Adjust the distance between the tips of the two ignition electrodes so that the electric spark generated can immediately ignite the oil mist.
CB/T3642-94
4.3.2 When the system is in good condition, the action of the sequence controller must ensure that the fan is started before the boiler is ignited and burned. When the air door is in the fully open position, the furnace membrane and the flue are scavenged. After the boiler is turned off, the fan should be temporarily kept running to scavenge the furnace and the flue. The setting time of scavenging should be in accordance with the requirements of the original boiler. If there is no original data, it can be specified in Table 1. Table]
Before ignition and combustion
After simmering
The setting time of the solenoid valve opening should not be more than the appearance of the electric spark. When there is an ignition burner, the setting time of the main solenoid valve opening should not be earlier than the appearance of the ignition flame. If the ignition fails, the setting time of the solenoid valve from opening to closing should not be greater than the provisions of Table 2.
Ignition mode
Safe ignition time
(electromagnetic balance from opening to closing)
Direct ignition
Indirect ignition
The pressure regulator and temperature regulator to be replaced should be adjusted according to the requirements of the ship repair acceptance paper for their pressure values ​​(steam pressure is too high or too low, oil pressure is too low) and temperature values ​​(oil temperature is too high or too low). 4.3.5 Under full load conditions, adjust the air-oil ratio so that the air-oil volume can burn well under the condition of complete and sufficient mixing, without coking and black smoke. 4.3.6 The flame monitor must be able to effectively monitor the flame during the ignition and operation of the boiler. When the ignition fails, the electromagnetic valve will be automatically cut off according to the time specified in Table 2; when the fault flame is extinguished during operation, the electromagnetic valve can be automatically cut off within 6S.
4.4 Acceptance
The effectiveness test of the automatic sequence control of the boiler from starting, pressure increase to shutdown shall be conducted at least twice.
The effectiveness test of the mutual conversion between light oil, heavy oil and fuel oil shall be conducted at least twice. The effectiveness test of the mutual conversion between the automatic control and manual operation of the boiler combustion shall be conducted at least once.
The boiler combustion control system shall conduct shutdown and alarm tests at least twice in the following conditions.
a. Ignition failure or flameout due to burner failure; b. The boiler outlet steam pressure is higher than the specified value (must be below the safety valve trip pressure);
c. The fuel injection pressure is lower than the specified value;
d. The fuel temperature is lower than the specified value;
e. The strong ventilation of the furnace fails,
T. The boiler water level drops to the specified limit low water level. Additional remarks:
This standard is proposed by the Ship Repair Sub-Technical Committee of the National Technical Committee for Standardization of Marine Ships.
This standard is under the jurisdiction of Tianjin Ship Repair Technology Research Institute. This standard was drafted by Shanghai Shipyard.
The main drafters of this standard are Zhang Ping, Chen Beijian and Luo Yuhui. 48
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