Electric steam generator, also known as inspection-free small electric steam boiler, micro electric steam boiler, etc. , is a kind of micro-boiler which can automatically replenish water and heat, and continuously produce low-pressure steam. Small water tank, water pump and control operating system are integrated without complicated installation, as long as the water source and power supply are connected. It mainly provides necessary dry steam for canteens, dry cleaners, steaming rooms and steam irons, and is often used in food factories, bean products factories and clothing factories.
As the water quantity of the electric steam generator is designed to be less than 30L, the installation and use of the electric steam generator are not subject to inspection and management by the technical supervision department. The boiler defined in the Regulations on Safety Supervision of Special Equipment refers to the equipment that uses various fuels, electricity or other energy sources to heat the contained liquid to a certain parameter and output heat energy to the outside. Its scope is defined as a pressure steam boiler with a volume greater than or equal to 30L; Pressurized hot water boiler with outlet water pressure greater than or equal to 0. 1 MPa (gauge pressure) and rated power greater than or equal to 0. 1 MW; Organic heat carrier boiler.
Second, the principle of electric steam generator
Its basic working principle is: through a set of automatic control devices, the liquid controller or the high, middle and low electrode probes feed back the on and off of the water pump, the length of water supply and the heating time of the furnace lining during operation; With the continuous output of steam, the highest steam pressure set by the pressure relay keeps the water level in the furnace down. When the water level is low (mechanical) or medium (electronic), the water pump will automatically replenish water, and when the water level is high, the water pump will stop replenishing water. At the same time, the electric heating tube in the furnace continues to generate heat and steam. The pointer pressure gauge on the panel or at the top immediately displays the steam pressure value, and the whole process can be automatically displayed through the indicator light.
Third, the structure of electric steam generator
The electric heating steam generator is mainly composed of water supply system, automatic control system, furnace lining and heating system and safety protection system.
1. The water supply system is the throat of the automatic steam generator, which continuously supplies dry steam for users. When the water source enters the water tank, the power switch is turned on. Driven by the automatic control signal, the high-temperature electromagnetic valve is turned on, the water pump works, and it is injected into the furnace through the one-way valve. When the solenoid valve and one-way valve are blocked or damaged and the water supply reaches a certain pressure, it will overflow back to the water tank through the overpressure valve, thus protecting the water pump. When the water tank is out of power or there is residual air in the water pump pipeline, only air enters and there is no water. As long as the water is quickly discharged through the exhaust valve and the exhaust valve is closed when the water is sprayed out, the water pump can work normally. The most important component in the water supply system is the water pump. Most of them use multi-stage vortex pump with high pressure and large flow, and a few use diaphragm pumps or vane pumps.
2. The liquid level controller is the central nervous system of the generator automatic control system, which can be divided into electronic and mechanical types. The electronic liquid level controller controls the liquid level (that is, the water level difference) through three electrode probes with different heights, so as to control the water supply of the water pump and the heating time of the electric heating system of the furnace lining. The working pressure is stable and the application range is wide. The mechanical liquid level controller adopts stainless steel floating ball type, which is suitable for generators with large furnace volume. The working pressure is unstable, but it is convenient to disassemble, clean, maintain and repair.
3. Generally, the furnace liner is made of seamless steel tube special for boiler, which is slender and vertical. The electric heating tubes used in the electric heating system are mostly composed of stainless steel electric heating tubes of 1 or above, and their surface load is generally about 20 watts/cm2. Due to the high pressure and temperature when the generator works normally, the safety protection system can make it run safely, reliably and efficiently for a long time. Generally, the safety valve, one-way valve and exhaust valve made of high-strength copper alloy are used to implement three-level protection. Some products also add water level glass tube protection device, which increases the user's sense of security.
Fourth, the scope of application of electric steam generator
Widely used in washing and ironing industry: dry washer, dryer, washing machine, dehydrator, ironing machine, iron and so on. Packaging machinery industry: labelers and labelers are used together; Biochemical industry: fermentation tank, reaction kettle, jacketed pot, mixer, emulsifying machine and other equipment are used together; Food machinery industry: supporting the use of tofu machine, steamer, sterilization tank, packaging machine, coating equipment, sealing machine and other equipment; Other applicable industries: steam cleaning industry (oil fields, automobiles), hot water supply (hotels, dormitories, schools, mixing stations), concrete maintenance (bridges, railways), sauna bathing (leisure clubs), heat exchange equipment, etc.