Hitachi, Ltd.

Riichi Uchida

Katsumi Matsubara

Kazuaki Shiinoki

Kotaro Naya

Akira Suzuki

Tadashi Osaka

Sachio Sekiya

Hiroaki Matsushima

Yuki Akiyama

Seiji Tsuru

Hidetomo Mori

Tadashi Hayakawa

Koutarou Naya

Shigeru Sasaki

Akira Arai

Mitsuru Fujiwara

Masatoshi Muramatsu

Haruo Mishina

Eiji Yokoyama

Hajime Arai

Tsuneharu Takagi

Shinji Mitsuhashi

Kiyoshi Masujima

A vehicular air conditioning system for saving energy includes: a first indoor cooling heat exchanger for suctioning in and cooling the air within or outside a vehicle; an indoor air conditioning heat exchanger installed on the downstream cooling heat exchanger for regulating the temperature of the applicable air, a refrigeration cycle connected to the applicable indoor air conditioning heat exchanger, a heating element mounted in the vehicle, and a circuit for the machine coolant circulating between the applicable heating element and the applicable first indoor cooling heat exchanger, and in which the air flow path for air flowing into the indoor air conditioning heat exchanger is structured by merging a flow path passing through the first indoor cooling heat exchanger to a flow path not passing through the first indoor cooling heat exchanger, and is also configured to allow switching to either of the two flow paths.

Vehicular air conditioning system

A vehicular air-conditioning system includes: a vehicle interior air-conditioning apparatus which includes a device cooling circuit of a heat generating device mounted in a vehicle, and a refrigeration cycle circuit; and an intermediate heat exchanger for heat exchange between a device cooling medium of the device cooling circuit and an air-conditioning cooling medium of the refrigeration cycle circuit. A vehicle control apparatus is configured to determine a temperature of the cooling medium, and select a shorter control cycle timing of the vehicular air-conditioning system when the temperature of the cooling medium is greater than a predetermined temperature.

Vehicular air-conditioning system including a temperature-dependent control cycle

A vacuum pump apparatus comprises a male and female screw rotors meshing with each other, a casing for accommodating the male and female screw rotors and having a working space, a suction port and a discharge port both communicating with the working space, bearing portions for supporting shafts of the male and female screw rotors on the suction and discharge sides thereof. Shaft seal portions which are respectively disposed between the working space and each of the bearing portions and are adapted to seal the shafts of the male and female screw rotors on the suction and discharge sides thereof. Seal gas introducing device introduces seal gas into the shaft seal portions, and a controller controls the pressure of the seal gas introduced into the shaft seal portions.

Vacuum pump apparatus and shaft sealing device therefor

The screw type vacuum pump comprises a pump casing having a suction inlet and a discharge outlet, and a pair of rotors incorporated within the pump casing and meshing with each other to rotate in synchronized manner. The vacuum pump evacuates a reaction vessel, to which process gas is applied, to obtain a negative pressure condition of a predetermined level. Upon operation of the pump, inert gas is introduced into a compression working chamber directly or through a sealing portion disposed adjacent the discharge outlet. The introduced inert gas is adiabatically compressed therein to generate heat to heat the rotors and a casing wall. Further the inert gas effects a reduction of partial pressure of the process gas in the pump. Accordingly, a side reaction product is prevented from accumulating on the rotors and the casing wall.

Screw type vacuum pump with introduced inert gas

A screw fluid machine in which the distance between a point on each of bore walls and the axis of a male or female rotor decreases at a normal temperature in the vicinity of a high-pressure port as the point proceeds from the low-pressure side to the high-pressure side.

Screw fluid machine with high efficiency bore shape

A two-stage vacuum pump apparatus has a first stage of vacuum pump constituted by a screw-type vacuum pump and a second stage vacuum pump constituted by an oil-sealed rotary vacuum pump operative to maintain the back pressure of the first stage vacuum pump at a level ranging from 1 to 100 Torr., whereby a high level of vacuum can be attained in a system to be evacuated without any risk of contamination of the evacuated system by oil. Also disclosed is a method of operating the two-stage vacuum pump apparatus.

Two-stage vacuum pump apparatus and method of operating the same

The present invention provides a screw vacuum pump unit in which both a screw block and a driving motor are mounted on one side surface of a casing of a speed change gear, both axes of a male rotor and a female rotor in the screw block are arranged in vertical adjacency within a substantially perpendicular virtual plane, and suction ports and discharge ports are arranged on both sides with the vertical plane intervening therebetween, whereby maintenance can be facilitated.

Screw vacuum pump unit

A screw vacuum pump including a plurality of casings and a pair of rotors defining a plurality of working chambers. The working chambers are constituted by working chambers whose volumes undergo a change as the rotors rotate, and working chambers whose volumes undergo substantially no change as the rotors rotate. The screw vacuum pump is capable of achieving pressure of 10.sup.-1 to 10.sup.-4 Torr or a low or medium vacuum by means of a single pump operating in a single stage.

Screw type vacuum pump

An operation control system of a rotary displacement type vacuum pump capable of reducing a starting torque of the vacuum pump includes a suction regulating valve and a pressure sensor for monitoring suction pressure located in a suction passage of the vacuum pump, an inverter electrically coupled to a variable speed electric motor for driving the vacuum pump and a control unit. The control unit is operative, when the vacuum pump is started, to keep the suction regulating valve in a closed position until the value of suction pressure monitored by the pressure sensor reaches a predetermined upper limit value and to gradually increase the rpm. of the variable speed electric motor. The control unit is further operative to produce a signal for increasing or decreasing the rpm of the variable speed electric motor so as to bring the value of suction pressure monitored by the pressure sensor to the vicinity of a predetermined lower limit value.

Operation control system of rotary displacement type vacuum pump

An oil-free rotary displacement compressor including a casing having a main casing defining a compression space, a pair of rotors housed in the compression space and each having a screw thread portion and shaft portions, radial bearings and thrust bearings for journalling the rotors, shaft sealing means for sealing the shaft portions to avoid gas leaks from the compression space to outside and entry of oil into the compression space from the bearings. Floating type screw seal rings, each formed on the inner surface with a spiral screw thread and a root of thread, are each fitted over one of the suction-side shaft portions and supported by the casing in such a manner as to be movable in both the radial and the axial directions with respect to the casing. Stationary type screw seal rings, each formed with a spiral screw thread and a root of thread are each fitted over one of the discharge-side shaft portions and supported by the casing in such a manner as to be movable only in the axial direction with respect to the casing.

Oil-free rotary displacement compressor

Screw fluid machines are for use as a compressor for generating high pressure gas, a cooling-medium-compressing compressor for use in a refrigerator or an air conditioner. The fluid machine includes a rotor casing, two side-casings, a pair of screw rotors, and accessories such as silencer, a gas cooler, an oil cooler, and an oil tank. The rotor casing includes an outer wall, an inner wall and interconnecting members or ribs which interconnect the outer wall and the inner wall, with a space being provided between the outer wall and the inner wall. This space is partitioned into two or more spaces by means of the aforesaid interconnecting members. A working chamber or space is provided inwardly of the inner wall and has an inlet port and a discharge port. Both side-casings are secured to the opposite end faces of a rotor casing through the medium of flanges and are provided with a passage adapted to bring two or more spaces thus partitioned, into communication with each other. A pair of rotors are housed in meshing relation in a working chamber in the rotor casing. In addition, accessories are housed in spaces thus partitioned.

Growing community of inventors

Ibaraki, Japan

Riichi Uchida