Abstract: A gas compressor for vehicle braking systems controlled by compressed air can be operated under load or in idle operation. In idle operation, no compressed air is produced. In operation under load, the gas compressor produces compressed air as required by the pressure medium installation. During prolonged operation of the gas compressor at a relatively high operating speed, for example, during travel on super-highways, the power consumption can be decreased and thereby also the production amount of the gas compressor, without having to switch the gas compressor over into idle operation. A clearance volume of less volume than the nominal volume of the gas compressor is provided which can be connected via a valve to the compression chamber of the gas compressor, thereby making it possible to enlarge the compression volume. In addition, a process for the control of the auxiliary valve takes into account different operating magnitudes of the gas compressor and other elements of the vehicle.

Abstract: A safety valve arrangement for an installation operating with a pressure medium has a pressure medium input and a pressure medium output connected by a valve. The valve comprises a valve seat and a valve closing element. The valve closing element is moveable between an open position and a closed position and has an active surface that is subjected to the pressure medium in the opening direction of the valve. The valve closing element also has an auxiliary surface that is subjected to the pressure medium in the opening direction of the valve only when the valve closing element is lifted from the valve seat. A spring arrangement holds the valve closing element closed and the valve closing element moves from a closed position to an open position when the pressure medium acting upon the valve closing element is greater than the opposing force of the spring arrangement acting upon the valve closing element.

Abstract: The inventive device produces compressed gas. It is provided with a compressor, wherein the compressor has a compression chamber (25), a suction chamber (10) and a pressure chamber (6). The compression chamber (25) can be connected to the suction chamber (10) via a suction valve (12, 21, 54) and to the pressure chamber (6) via a pressure valve (3). When the receiving-end pressure reaches a predetermined level, the pressure chamber (6) is connected to a compressed-air supply container (44). This connection is via a device for the discontinuation of compressing action (23, 51). In addition, the pressure in the pressure chamber (6) is monitored by a control valve (26), which is a sensing device with a control output (38). The sensing device (26) is designed to produce a control signal at the control output (38), when the pressure in the pressure chamber (6) or compression chamber (25) of the compressor reaches or exceeds a predetermined value.

Abstract: For working up concentrated, preferably partially condensed phosphoric acid which is contaminated with organic components, the phosphoric acid is first thoroughly mixed with fine-grained sand in a weight ratio of (0.5 to 1.5):1. Then, to neutralize the mixture, a basic, oxygen-containing calcium compound is added, while the thorough mixing is continued, until a 10% aqueous suspension of the mixture to which the calcium compound has been added has a pH between 5 and 11. Finally, the mixture which contains the calcium compound is commminuted after cooling.