The DYC-Q series electromagnetic differential pressure valve loop flange is a specialized vacuum valve installed on the inlet of a mechanical vacuum pump. Its working principle is that the power supply of the mechanical pump and the power supply of the solenoid valve coil are connected to the same power supply. When the mechanical vacuum pump suddenly loses power or stops running due to work needs, the valve uses atmospheric pressure to automatically close the valve core, cut off the channel connected to the vacuum system, and at the same time, release air into the pump to prevent the mechanical pump oil from returning to the vacuum system, which plays a protective role in the vacuum system and is conducive to the restart of the mechanical pump. The applicable working medium is air and non corrosive gases.