A pilot assisted self-powered valve actuator for vertical action valves (global valve, gate valves, and others), rotation action valves (ball valves, butterfly valves, and other plug valves), and four-way modulation valves to control flow from 0% to 100%. It consists of actuator chamber which is connected to both valve inlet and outlet, an actuator plug which is positioned by one or two coil springs and is driven under the pressure difference from inlet and outlet of the valve, and a pilot valve and bleeding hole(s) which control and adjust the pressure on one side of the actuator plug. The pilot assisted self-powered valve provides superior control performance and costs a fraction of the pneumatic and/or electrical control actuators.

In a throttle device, a needle member (20) includes a tapered portion (20P) having a taper angle (2), and a length (X) along a center axis from a position (20PS) to an apical surface of the tapered portion (20P) is set to a value equal to or above a prescribed amount of lift (Lcos.sup.2 ), where the position (20PS) is a position corresponding to an edge (22as) of a valve port (22a) in a state where the tapered portion (20P) is inserted in the valve port (22a) and establishes a closed state of the valve port (22a).

An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

Provided are a power element and an expansion valve using same that are capable of obtaining a desired temperature/flow rate characteristic while being low cost. A power element includes a diaphragm; an upper lid member that is joined to one side of an outer circumferential portion of the diaphragm and forms a pressure working chamber PO with the diaphragm; an annular support point adjustment member that is joined to another side of an outer circumferential portion of the diaphragm; a receiving member that is joined to the support point adjustment member and forms a refrigerant inflow chamber LS with the diaphragm, and a stopper member housed in the refrigerant inflow chamber LS, wherein the diaphragm is capable of coming into contact with a support point of the support point adjustment member.

A throttle device to decompress a refrigerant and to deliver the refrigerant to an evaporator, may have an opening level of a needle valve controlled following a condensation pressure. Inside a case including a primary chamber connected to the condenser and a secondary chamber connected to the evaporator, a valve seat formed with a port and a guide integral to the valve seat are provided. A spring to energize the needle valve toward the port side is provided inside the guide. The guide guides the needle valve along a line allowing an opening level of the port to be variable. A space between the guide and the case forms a channel to deliver the refrigerant from the port to the secondary chamber. A rear space of the needle valve within the guide forms an intermediate chamber. An intermediate channel introduces the refrigerant from the port into the intermediate chamber.

A method is disclosed for uniformly cooling a cooling plate of a heat generating device. Sub-cooled refrigerant is flowed through a thermal expansion valve and then into the cooling plate as a two-phase refrigerant where the refrigerant is superheated. Any refrigerant remaining in a fluid state before reaching a sensing portion associated with the thermal expansion valve and exiting the cooling plate can be completely vaporized by a recuperative heat exchanger. The superheated refrigerant is then passed to the sensing portion so that the superheated refrigerant directly transfers heat to a fluid within the sensing portion and causes a pressure change that is communicated to a needle of the thermal expansion valve.

A throttling device is equipped with a valve seat in which a valve port for connecting a primary chamber and a secondary chamber is formed, a needle valve, a needle section which is inserted into the valve port, a guide section for guiding a slide shaft of the needle valve, and a coil spring for biasing the needle valve in a valve-closing direction. The guide section and the coil spring are positioned on the primary chamber side. The coil spring is covered by a stopper section. A gap between the stopper section and a main body case functions as a main body path for delivering a refrigerant from the primary chamber to the valve port.

A throttling device is equipped with a valve seat in which a valve port for connecting a primary chamber and a secondary chamber is formed, a needle valve, a needle section which is inserted into the valve port, a guide section for guiding a slide shaft of the needle valve, and a coil spring for biasing the needle valve in a valve-closing direction. The guide section and the coil spring are positioned on the primary chamber side. The position of the needle valve in the valve-closing direction is restricted by a stopper section in a manner such that the minimum gap between the needle valve and the valve port is maintained. Furthermore, the needle valve is not seated on the valve seat.

In a throttle device, a guide section including a small-diameter hole which slidably guides a guide stem of a needle member is formed upstream side portion from a communicating hole-in a guide tube.