Abstract: There is proposed a nitrogen treating method for nitrogen compounds which is capable of removing nitrogen compounds efficiently and achieving a downsizing of equipment and a decrease in costs. The nitrogen treating method is a method for treating nitrogen compounds in for-treatment water by an electrochemical process, wherein as a metal material which constitutes a cathode, a conductive material containing or covered with an element in the group Ib or IIb of the periodic table is used.

Abstract: A waste water treatment device is provided in which removal of phosphorus and removal of nitrogen can efficiently be carried out and a decrease in size of the device and a decrease in cost can be achieved. The waste water treatment device includes a waste water treatment chamber; at least one set of electrodes disposed so that at least a part of the electrodes are immersed in waste water in the waste water treatment chamber, at least one of said electrodes dissolving out, by electrolysis, iron ions or aluminum ions for precipitating and removing phosphoric acid ions in waste water; a power source for supplying an electrolytic current to the set of electrodes; a control section for controlling the power source; and a metallic catalyst which is disposed in the vicinity of at least one of the sets of electrodes and which effects a denitrifying reaction with hydrogen in waste water.

Abstract: There are provided an ozone producing method and apparatus capable of significantly increasing an amount of ozone produced in for-treatment water. In the ozone producing method of the present invention, a noble metal is used as a material constituting the anode, and the for-treatment water contains halogen ions or a compound containing halogen ions.

Abstract: In a gas compressor-expander according to the invention, a partition wall 19 between a space 21 in the rear of a piston and a crank chamber 12 has a piston rod 22 slidably extending therethrough and a seal device 9 surrounding the piston rod 22. The seal device 9 comprises a first seal member 93 having a high sealing property against a flow from the crank chamber 12 toward the space 21, an intermediate chamber 91 provided in the vicinity of the first seal member 93 at one side thereof toward the space, a second seal member 95 disposed in the vicinity of the intermediate chamber 91 at one side thereof toward the space, and a communication channel 96 for holding the intermediate chamber 91 and the crank chamber 12 in communication with each other. This construction gives a prolonged life to the seal device and prevents impairment of the refrigeration capacity of the gas compressor-expander.

Abstract: An object of the present invention is to provide a waste water treatment device in which removal of phosphorus and removal of nitrogen can efficiently be carried out and a decrease in size of device and a decrease in cost can be intended, and the gist of the waste water treatment device comprises a waste water treatment chamber; at least one set of electrodes disposed so that at least a part of the electrodes are immersed in waste water in the waste water treatment chamber, at least one of said electrodes dissolving out, by electrolysis, iron ions or aluminum ions for precipitating and removing phosphoric acid ions in waste water; a power source for supplying an electrolytic current to the set of electrodes; a control section for controlling the power source; and a metallic catalyst which is disposed in the vicinity of at least the other of the set of electrodes and which acts on a denitrifying reaction with hydrogen in waste water.

Abstract: The gas compression/expansion apparatus comprises: a working section for compressing/expanding therein a working gas by pistons each connected with a rod; a drive section including sliders each connected at one end thereof with the rod and connected at one end thereof with a guide for guiding the slider, and a drive mechanism for reciprocating the sliders; and a separator for fluid dynamically separating the working section from the drive section, the separator permitting said rod to pass through said separator. The separator further includes an oil seal arrangement. Formed inside the separator is an intermediate chamber which allows the rod to pass there through. The inner radius of the intermediate chamber is greater than the radius of the rod plus the oil deposited on the rod. The guide includes a guide space formed such that the distance between the slider at its upper dead point and the wall of the separator facing the slider is larger than the thickness of the oil on the slider.

Abstract: An improved heat exchanger for use in a gas compression/expansion apparatus. The heat exchanger comprises: a tube connected with a compression/expansion space of a compression/expansion cylinder of the apparatus; a central cylinder coaxially disposed in the tube such that a narrow gap for the working gas is formed only between the central cylinder and the tube. The heat exchanger may liberate heat from, or providing heat to, the compression/expansion cylinder through heat transfer between the working gas in the tube and an ambient medium surrounding said tube. The heat exchanger is capable to serve as a low/high temperature heat source for an external heat load.

Abstract: An apparatus for compressing/expanding a working gas (compression/expansion apparatus), including: a cylinder; a piston for compressing/expanding said working gas in a working space (front space) of said cylinder; a crank mechanism connected with a piston rod of said piston via an oil seal; a crank chamber for housing therein said crank mechanism and communicating with said cylinder via said oil seal, said apparatus comprising: a first tube allowing for a unidirectional flow of the working gas from said crank chamber to said front space in said cylinder, said first tube having therein an oil filter and a first check valve; and a second tube allowing for a unidirectional flow of the working gas from said front space to a second space (rear space) behind said piston in said cylinder, said second tube having therein a second check valve.