Abstract: For a LNG (liquid natural gas) liquefaction system or plant that includes a gas turbine fueled by vaporized LNG and which receives compressed air, via an air compressor, as an input, a means and method to use relatively colder LNG vapor, in a heat exchanger disposed before the inlet to the turbine's air compressor, to remove heat from the air being inputted to the air compressor to improve overall efficiency of the systems or plants.

Abstract: A method and an apparatus for controlling a displacement-type fluid machine which handles fluid including gas and/or liquid for increasing or decreasing pressure of the fluid or transporting the fluid including the use of an alternating current motor for driving the displacement-type fluid machine and a frequency converter which is capable of conducting frequency conversion up to a range higher than the power source frequency to adjust the number of revolutions of the motor. Wherein the number of revolutions is adjusted so that input current to the motor is kept constant, regardless of any change in operating pressure of the displacement-type fluid machine, whereby the displacement-type fluid machine is operated maintaining the process values within an allowable limit without effecting repeated actuation and stopping of the machine.

Abstract: A vacuum valve controller for a vacuum sewer system having a suction pipe which is communicated with a vacuum system by opening a vacuum valve, and which is cut off from the vacuum system by closing the vacuum valve, so that soil water in a soil water basin is sucked through the suction pipe and sent to a predetermined place by opening said vacuum valve is disclosed.

Abstract: A vacuum valve controller for a vacuum sewer system including a suction pipe (12) which is communicated with a vacuum system (15) by opening a vacuum valve (14), and which is cut off from the vacuum system by closing the vacuum valve (14) is disclosed. Soil water in a soil water basin (10) is sucked through the suction pipe (12) and sent to a predetermined place by opening the vacuum valve (14). The vacuum valve controller is provided with a control device (20) which closes the vacuum valve (14) by detecting that the suction pipe has begun to suck air from a change of the pressure difference between two points (16 and 17) in the suction pipe (12) which are different in height from each other, which provide a vacuum valve controller for a vacuum sewer system, which is simple in structure, easy to maintain and capable of stable operation.

Abstract: A vacuum valve including a casing having an inlet opening, an outlet opening, and a valve seat, a valve body accommodated in the casing and adapted to move rectilinearly between a position where it rests on the valve seat and a position which is away from the valve seat, means for pressing the valve body to the resting position, and a piston chamber in which an air differential pressure acts so as to separate the valve body from the valve seat against the pressing means, wherein the casing has a front wall portion which is at an acute angle to the direction of a streamline connecting the inlet and outlet openings and so that elongate foreign matter flowing in from the inlet opening can readily flow out, and side and rear wall portions expanding outwardly in a direction approximately perpendicular to the axis of the valve from a position near the valve seat so that bulk foreign matter flowing in from the inlet opening will not get caught between the valve body and the casing inner wall.

Abstract: A vacuum pump control apparatus for an evacuating-type waste water collecting system is disclosed. In the system, waste water discharged from houses and facilities is collected into a water collecting tank by vacuum sewer pipes provided with a negative pressure therein, and the waste water collected in the water collecting tank is discharged by a booster pump while the air in the water collecting tank is discharged by a vacuum pump. The vacuum pump control apparatus comprises a gas-liquid ratio detection arrangement for detecting the ratio of the amount of air to the amount of waste water to be collected into the water collecting tank, and a control system for regulating the operating time of the vacuum pump based upon the gas-liquid ratio detected by the gas-liquid ratio detecting arrangement, so that a target value of the gas-liquid ratio is recovered when it falls below the target value.

Abstract: A vacuum interface valve is used in a vacuum sewerage system in which sewage is transported under the influence of vacuum to a wastewater treatment station or a public main sewer. The vacuum interface valve includes a casing having an inlet, an outlet and a valve seat, a valve member which is linearly movable between a position engageable with the valve seat and a position away from the valve seat, an element for urging the valve member into engagement with the valve seat, and a vacuum device for lifting the valve member under the action of a vacuum to cause the valve member to disengage from the valve seat. The inner wall of the casing is bulged outwardly from the vicinity of the valve seat in a direction substantially perpendicular to an axis of the valve member, and a space is defined in the vicinity of the valve seat in the casing so that foreign matters are not caught between the inner wall of the casing and the valve member.

Abstract: A vacuum type sewage collecting system, for collecting sewage from a plurality of houses or the like, stores sewage in a sewage reservoir and then delivers the sewage to a sewage treatment station through a vacuum valve and a vacuum sewage pipe. A controller is provided for properly controlling opening/closing operations of the vacuum valve. The controller includes a first vacuum chamber connected to the vacuum sewage pipe via a fluid flow resisting device, a second vacuum chamber likewise connected to the vacuum sewage pipe, an atmospheric pressure introducing unit for introducing an atmospheric pressure into the first vacuum chamber when a detected quantity of sewage stored in the sewage reservoir exceeds a predetermined value, and a shifting unit for selectively introducing negative pressure to the vacuum valve to open or close the latter depending on the present differential pressure between the first vacuum chamber and the second vacuum chamber.

Abstract: A vacuum-type sewage collecting apparatus collect sewage discharged from a plurality of houses or facilities in an accumulating tank through a vacuum sewage pipe network, the inner pressure of which is negative. The vacuum sewage pipe network includes a plurality of upper stream pipes and lower stream pipes fastened to each other in a branch-like fashion. Each lower stream pipe has a sawtooth-like shape formed by alternately disposed downwardly-sloping portions extending gently downwards toward said accumulating tank, and lift portions fastened to the lowermost portion of a respective downwardly-sloping portion and extending upwardly with a steep slope. The upper stream pipe is connected to the lower stream pipe in a range in which a horizontal plane, which extends through an upper end portion of the lower stream pipe at the position in which the downwardly-sloping portion adjoins the lift portion, is higher than the center of the lower stream pipe.

Abstract: A laying structure for a vacuum sewer pipe of a vacuum sewage collecting system for collecting sewage discharged from homes and facilities into a collecting tank through a vacuum sewer pipe kept negative in pressure internally is disclosed. The vacuum sewer pipe includes a portion laid in a plain topography which comprises a downward pitch portion sloped toward downstream, and a short upward pitch portion connected to the downstream end of the downward pitch portion to return a depth of the vacuum sewer pipe to an original level, the downward pitch portion and the upward pitch portion are alternated at least once. The upward pitch portion starts from a spot deepened from the original laying level by a depth corresponding to 0.8 to 1.0 times of a bore of the vacuum sewer pipe. By this arrangement, an air lock is not produced at the upward pitch portion even if the quantity of air flowing in the vacuum sewer pipe is low.

Abstract: A vacuum-type sewage collecting apparatus is arranged in such a manner that sewage discharged from the houses or facilities is once accumulated in a cesspool, and the sewage accumulated in the cesspool is then collected through a vacuum valve and a vacuum sewage pipe, the interior of which is under a negative pressure. The vacuum valve is operated by negative pressure taken from a vacuum source and supplied to the vacuum valve via a connecting pipe. The negative pressure for operating the vacuum valve is taken from a portion of a vacuum sewage pipe which is elevated at a level higher than that of the vacuum valve and is disposed downstream of the vacuum valve. Alternatively, the negative pressure may be directly taken from an accumulating tank, the inner pressure of which has been evacuated by a vacuum pump, from a pipe which establishes a connection between the accumulating tank and the vacuum pump, or from a tank connected to the pipe connecting the accumulating tank and the vacuum pump.