摘要 |
When the valve is closed, for example at normally-open type valve, the operating voltage applied to the electromagnet is initially set to the minimum operating voltage (6 V, for example), then raised to a voltage (12 V, for example) where sealing caused by contacting force between the valve body and the valve seat is ensured. The voltage is raised almost simultaneously with the contact of the valve body with the valve seat, or slightly earlier or later. Thus, when the valve is closed, the valve body speed when it reaches the valve seat is low, making the operational noise at valve closing smaller. Also, since the operating voltage of the electromagnet is raised later, sealing of the closed valve is ensured.
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