First, the importance and characteristics of diesel fire pumps

Diesel fire pumps as the key equipment in the field of fire fighting, compared with electric pumps, has significant features and advantages. It is equipped with an independent power supply system -- battery, this feature makes its start and run completely free from the limitations of the utility power. In the fire scene, once the utility power failure due to interruption, electric pumps can not work, diesel fire pumps will be able to quickly play a role, become a reliable guarantee of fire rescue.

Usually, diesel fire pumps as a standby facility, only in the receipt of fire signals, and electric water pump failure or power outages in emergency situations will automatically start. In some places where the reliability of fire protection is highly required, such as large shopping centers and chemical parks, the existence of diesel engine fire pumps provides double insurance for fire safety. When the system detects an ultra-low pressure signal, the diesel engine fire pump can quickly respond to start to ensure a continuous supply of water for firefighting. In order to ensure the stability of its work with the electric pump, and its supporting electric pump control cabinet should also have ultra-low pressure pump starting device, and the lower limit of the two pumps need to maintain a certain pressure difference.

Second, the specific steps of routine maintenance

(A) fuel and lubrication system maintenance

Fuel tank inspection: regularly check the fuel tank fuel is to ensure the normal operation of diesel fire pump basis. The fuel tank should be closely observed the amount of fuel storage, according to the actual use of fuel in a timely manner. When adding fuel, be sure to choose the fuel varieties that meet the requirements of the equipment, and avoid the use of poor-quality fuel, so as not to cause damage to the fuel system.

Oil sump oil check: the oil in the sump plays a key role in lubricating the normal operation of the diesel engine. When checking, observe whether the oil level reaches the mark on the oil scale. If the oil level is insufficient, the appropriate amount of oil should be added to the required amount, but be careful not to exceed the upper limit of the scale mark, otherwise it may lead to abnormal engine operation.

Injector pump governor oil check: for the injection pump governor oil plane, also need to check. If it does not reach the prescribed mark, you should add enough oil in a timely manner. It should be noted that some of the injection pump governor does not have a ruler, in which case the inspection steps can be omitted.

Grease check and replenishment: the oil injection point of the pump needs sufficient grease to ensure its normal operation. The diesel engine circulating water pump on the injection nozzle removed, observe which the lubricating grease is sufficient. If it is insufficient, use a grease gun to inject enough lubricating grease to reduce the friction between parts and extend the service life of the equipment.

(ii) cooling system maintenance

Water tank water volume check: the water in the tank is a key factor in ensuring the normal cooling of the diesel engine. In the daily maintenance, we should always pay attention to the amount of water in the water tank, once found insufficient, it should be timely supplemented with clean fresh water, such as tap water or clean river water.

Water quality requirements: It is strictly prohibited to use groundwater directly as the supplemental water in the water tank, because groundwater contains more minerals, which is easy to form scale in the water tank. Scale will affect the cooling effect, resulting in diesel engine temperature is too high, and then lead to failure. If only groundwater can be used, it must be softened before use.

The use of antifreeze: in the northern ambient temperature below freezing in the region, in order to prevent the water tank from freezing, the need to configure the appropriate freezing point of the antifreeze according to the local minimum temperature. Antifreeze can not only prevent the water tank from freezing, but also play a role in anti-corrosion and rust, which helps to extend the service life of the water tank and cooling system.

(iii) Overall inspection of equipment

“Three leaks” check: Regularly check the sealing surface of the oil pipe and water pipe joints to see if there is any leakage. Once the leakage is found, measures should be taken immediately to repair it, so as to avoid damage to the equipment caused by the leakage of oil or water. At the same time, check the exhaust pipe, cylinder head gasket and whether the supercharger is loose or leakage phenomenon, if there is a problem should be excluded in a timely manner.

Attachment installation check: check the installation of each attachment of the diesel engine to ensure that each attachment is firmly installed, the ground screws and the connection with the working machinery is firm and reliable. Any loose parts may cause vibration during the operation of the equipment, affecting the normal operation of the equipment, or even lead to component damage.

Injector pump transmission connecting disk check: check whether the connecting screw of the injector pump transmission connecting disk is loose. If the screw is loose, it will affect the injection advance angle, which in turn affects the performance of the diesel engine. At this point, the injection advance angle should be recalibrated, and tighten the connection screws to ensure the normal operation of the diesel engine.

(D) equipment cleaning

Keep the diesel engine and ancillary equipment clean appearance, help equipment heat dissipation and prevent corrosion of components. Use a dry cloth or diesel-impregnated rags to wipe oil, water and dust from the surface of the fuselage, turbocharger, cylinder head cover, air filter, etc. For charging generator, radiator, fan and other surface dust, you can use compressed air to clean or blow clean.

Third, the preparatory work before starting

Diesel fire pumps in the structure than the electric pump is more complex, so the preparatory work before starting is also more cumbersome.

Voltage check: before starting, the first thing to check the control cabinet on the voltmeter display is 24 V. If the voltage is lower than 24 V, you should promptly find out why and troubleshooting to ensure that the equipment has the normal start of the power conditions.

Overall checking: make a comprehensive check on each part of the diesel engine to ensure that each part is normal and each accessory is connected reliably. If abnormal phenomenon is found, it should be dealt with in time to avoid problems in the starting process.

Oil check: check again whether the oil in the oil sump, injection pump and governor reaches the specified oil level position. If the oil is insufficient, the same type of oil should be added to ensure that the equipment is adequately lubricated during startup and operation.

Water tank inspection: check whether there is enough water in the water tank. For equipment that uses an open circulation cooling system, it is also necessary to connect the water source to ensure that the cooling system works properly.

Fuel system venting: Use the hand pump on the fuel delivery pump to pressurize fuel into the fuel system. At the same time, loosen the bleeder screw on the injection pump to remove air from the fuel system. When no more gas is discharged at the bleeder screw, tighten the screw and continue pumping fuel until there is return fuel in the return pipe, and finally tighten the hand pump.

High-pressure fuel pipe exhaust (optional step): in general, in turn, loosen the cylinder injectors on the high-pressure fuel pipe connector nut, the governor handle is placed in the position of the diesel engine operation, turn the diesel engine, discharge the high-pressure fuel pipe in the air this step can be ignored. However, when the startup fails, this step should not be ignored to ensure that fuel can enter the cylinder smoothly.

Crankshaft rotation: For a new engine or a diesel engine that has been parked for more than 5 days without being used, rotate the crankshaft 3 - 5 times before starting to give the parts initial lubrication and to reduce wear and tear during startup.

Preheat plug check (low temperature environment): Check whether the preheat plug is normal when the temperature is below 5℃ and the equipment has a preheat starting device. The resistance of the preheat plug of 24V rated voltage is about 0.025Ω under normal condition, and the resistance of the preheat plug of 12V is smaller. If the preheating plug fails, it should be replaced in time to ensure that the equipment can be started smoothly in a low-temperature environment.

Fourth, regular inspection and daily management

(A) regular inspection

In order to improve the responsiveness of the diesel fire pump to fire signals, it is recommended that a weekly inspection. Taking into account the water hammer effect and the characteristics of the diesel engine itself, the inspection should be started at low speed diesel engine, and then slowly accelerate to the fire required speed (1500r/min - 3000r/min). When the water temperature, oil temperature have reached 60 ℃, can gradually decelerate, but before stopping still need to idle (300 - 750r/min) running 2 - 3min, so as to avoid sudden stopping due to overheating of the supercharger caused by the supercharger bearing bite. After stopping, the speed should be adjusted to 1500r/min - 3000r/min, in order to prepare for firefighting needs. Because the inspection process of diesel fire pump is more complicated, if there is no special requirements of customers, it is generally recommended to use manual inspection.

(ii) Daily management

Perfect daily management is the key to ensure the reliability of the entire control system. Although the diesel engine fire pump has a high degree of automation, but the human damage factor may lead to the loss of its function. The pump room key should be managed by a person, regularly check whether the equipment parts are lost or damaged by other factors, while checking whether the parameters of each component are scientific and reasonable.

In daily life, the proper maintenance of fire pumps is a systematic and detailed work, covering a wide range of aspects from daily inspection, regular maintenance to start-up preparation as well as inspection and daily management. Only in strict accordance with the requirements of every aspect of the work, to ensure that the fire pump at the critical moment can run stably, effectively extend its service life, for fire safety to provide a solid and reliable protection. Whether it is equipment management personnel or related operators, should fully recognize the importance of fire pump maintenance work, with a high degree of responsibility and professional skills to ensure the normal operation of equipment, guarding the safety of life and property.