SMC solenoid valve to open the valve, the gas is nearing completion in the shortest time; then the large valve closed, supplemented by a small valve to ensure the flow accuracy. This technology has been applied for many years abroad, the products from the world Electromagnetic valve Professional Company famous manufacturing. By the way of large flow of domestic oil tanks measurement or imitation is still the introduction of the foreign structure is more complex, less stable than the performance segment off valve, this product is not the world World renowned Professional Company system, because the market demand is not enough to lead to their interests. In fact, our oil using a large flow of domestic production of the double combination valve, the effect will be much better . Double combination valve is also used to control parameters of temperature, pressure, liquid level etc.. Large valve to ensure the basic amount, the amount of compensation for the small valve. In a relatively stable system parameters, this bit can control up to very High-precision. Better the system parameters change greatly, the rate of change is still subject to certain restrictions, such as temperature control system, influence is still heat inertia. So the use of the double combination valve properly meet the control at Prerequisite requirements relative to the control valve can significantly reduce costs. SMC solenoid valve is just a moment to complete the valve switching power, no power to keep the spool position. It has the advantage of saving energy, especially for battery power applications, and can not consider The temperature rise to the coil, long service life, high safety in high and low temperature, explosion and other occasions. There is a common mechanical maintenance and maintain a permanent magnet, and dual coil and single coil, single coil magnetic nodes to maintain The most simple. It is two kinds of state by changing the polarity of DC power to change the corresponding valve switch. The solenoid valve coil separate external wiring required to install additional switch, matching with the smart meter is It's so convenient. Electromagnetic valve for IC card prepayment gas and water meters are fitted with is key to the success of instruments, including the self holding solenoid valve technology is an important factor of success or failure.