Abstract: A multistage compressor includes a lower pressure side compression part, a higher pressure side compression part, an intermediate conduit placing the lower and higher side compression parts in communication, and a cooler disposed midway of the intermediate conduit for allowing gas to flow from the lower pressure side compression part to the higher pressure side compression part and for cooling the flowing gas. The cooler includes a drain outlet port. The compressor further includes an electromagnetic valve disposed at the drain outlet port and a controller for controlling the valve. The valve is opened when the compressor is started or re-started after a pause, is kept open during a predetermined period of time, and is then closed.

Abstract: A compressor which is provided with a safety device so that it is possible to detect occurrence of a primary accident, for example, breakage of a connecting rod, in the early stage. The compressor has a pressure sensor installed at a predetermined position in the compressor to detect the level of pressure at that position, a memory means for storing the behavior of the pressure change at the predetermined position that is obtained when the compressor is running in a normal state, a means for judging the behavior of the pressure change actually taking place at the predetermined position on the basis of an output from the pressure sensor and making a comparison between the actual pressure change behavior and the pressure change behavior in the normal state that is stored in the memory means, and a means for suspending the compressor when the actual pressure change behavior is different from the pressure change behavior in the normal state.

Abstract: A monoazo dyestuff composition comprising at least two different individual compounds of the formula ##STR1## wherein R.sup.1 and R.sup.2, independently of each other, are linear or branched alkyl having 1 to 4 carbon atoms and R is linear or branched alkyl having 1 to 5 carbon atoms, and where said individual compounds differ from each other in at least the R moiety. The monoazo dyestuff mixtures are used for the dyeing and printing of hydrophobic fibers such as high molecular weight polyesters of their mixtures with natural fiber material.

Abstract: An air compressor includes a crankcase, a cylinder secured to the crankcase, a crankshaft disposed inside the crankcase and adapted to be rotated by a drive means, a piston reciprocatively installed inside the cylinder, and a connecting rod for connecting the crankshaft to the piston. Part of the drive power circuit of the drive means is constructed so as to be cut off when displacement of the constituent members of the compressor other than predetermined displacement occurs and/or when the temperature inside the compressor rises above a predetermined value. Thus the passage of electric current to the drive means is cut off, the compressor being brought to a halt without causing secondary damage to develop.

Abstract: An air compressor is controlled such that when the pressure inside a tank for storing compressed air reaches a predetermined lower-limit value, the compressor is brought into a load running state to supply compressed air to the tank, whereas, when the pressure inside the tank reaches a predetermined upper-limit value, the compressor is brought into a stand-by state to suspend the supply of compressed air to the tank. The air compressor has a controller which judges the change in pressure inside the tank when the compressor is in a load running state on the basis of a signal delivered from a pressure sensor and effects control such that either one of two operations modes, that is, an intermittent operation mode in which the compressor stands by with the supply of electric power from a motor being cut off and a continuous operation mode in which the compressor stands by in a no-load state with the motor being supplied with electric power, is selected subsequent to a stand-by state.