Abstract: 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.

Abstract: A concentration correcting apparatus comprising a correction coefficient calculating means and a correcting means is shown and described. The correction coefficient calculating means calculates a correction coefficient for correcting the concentration of the material when the actual density of the medium at the measurement of the material is calculated in terms of the density of the medium under the reference temperature and pressure, from the results of the temperature measuring means and the pressure measuring means. The correcting means corrects the results of the material measuring means to a concentration under the reference temperature and pressure on the basis of the correction coefficient.

Abstract: An automotive air conditioner using a mixed type coolant of a higher boiling point coolant and a lower boiling point coolant. The air conditioner employs a stacking container connecting to an upper portion of a receiver for introducing a gas phased coolant which contains much of the lower boiling point coolant via a first valve. The stacking container is also connected to a suction side of a compressor via a second valve. The air conditioner becomes a mixing mode when the first valve closes a conduit and the second valve opens a conduit for introducing the lower boiling point coolant into a refrigerant circuit. The cooling ability is increased during the mixing mode. The air conditioner becomes a separating mode when the first valve opens the conduit and the second valve closes the conduit for separating the lower boiling point coolant circulating in the refrigerant circuit and stacking the same in the container.

Abstract: The automotive air conditioner uses a plurality of groups of coolant having different boiling points. The air conditioner uses both the lower boiling point coolant and the higher boiling point coolant when the air conditioner requires high cooling efficiency. The air conditioner separates the lower boiling point coolant from the higher boiling point coolant when the air conditioner does not require high cooling efficiency. In order to separate the lower boiling point coolant, the air conditioner has a rectifying circuit on which a controlling valve, a first pressure reducing means, a rectifying means, a second pressure reducing means and a heat exchanger is provided. The amount of coolant passing through the rectifying circuit is controlled in accordance with the temperature of the coolant downstream of the heat exchanger.