The direct-acting solenoid valve can operate reliably even at zero or low pressure differences, and can control large-diameter and high-pressure fluids with relatively small electromagnetic force.

1. Zero or extremely low pressure differential start-up: This is its core advantage. Even if the inlet pressure is zero, the electromagnetic force can directly open the pilot port, and then use the very small pressure (or gravity) of the medium itself to assist in opening the main valve. Therefore, it can be perfectly applied in low-pressure or zero-pressure scenarios such as the initial start-up of the system, water filling for pumps, and water replenishment from a high-level water tank to a low-level one.
2. Optimized balance of power and volume: Compared to direct-acting types that require huge electromagnetic force, its coil only needs to provide the force to open the pilot port, so the coil can be made smaller and the power consumption is lower. Compared to pilot-operated types, it does not need to rely on a stable pilot pressure differential.
3. Wide application range: It can cover a wide pressure range from vacuum to high pressure (usually up to 1.6 MPa or higher), and the diameter can be made relatively large (commonly from DN15 to DN100).
4. Fast response speed: Although the action process has two steps, due to the rapid pressure balance, the overall switching time is still very short.

1. Water pump water drawing and no-load protection system.
2. Junction control between vacuum system and pressure system.
3. Automatic water supply for high-level water tanks and water towers (the inlet pressure may only be static head and very small).
4. On-off control of cooling water circuits for large equipment (the water circuit may have no water pressure when the equipment starts up).

The step-by-step direct-acting solenoid valve, through its ingenious two-step structural design, achieves reliable control of large-diameter and wide-pressure-range (especially low-pressure end) fluids in a "leverage" manner, without significantly increasing the coil power consumption and volume.