Abstract: A hygienic, self-priming centrifugal pump (1) with a pump housing (4) provided with an inlet opening (2) and a pressure connecting piece (3), where an impeller wheel (7) can rotate inside said pump housing. The inlet opening (2) is connected with a liquid ring pump section (9) comprising an auxiliary housing (10) and a pump screw (11). The pump screw (11) is mounted on and in extension of the hub (7a) of the impeller wheel. A recycling pipe (15) for pump liquid connects the pressure connecting piece (3) of the centrifugal pump and the auxiliary housing (10) of the liquid ring pump section (9), optionally the inlet nozzle (16) or the inlet pipe (18) of the latter. All the surfaces in the pump housing (4) and the auxiliary housing (10) in direct contact with liquid should be smooth and rounded and without holes, crevices, beads or burrs.

Abstract: A hygienic, self-priming centrifugal pump (1) with a pump housing (4) provided with an inlet opening (2) and a pressure connecting piece (3), where an impeller wheel (7) can rotate inside said pump housing. The inlet opening (2) is connected with a liquid ring pump section (9) comprising an auxiliary housing (10) and a pump screw (11). The pump screw (11) is mounted on and in extension of the hub (7a) of the impeller wheel. A recycling pipe (15) for pump liquid connects the pressure connecting piece (3) of the centrifugal pump and the auxiliary housing (10) of the liquid ring pump section (9), optionally the inlet nozzle (16) or the inlet pipe (18) of the latter. All the surfaces in the pump housing (4) and the auxiliary housing (10) in direct contact with liquid should be smooth and rounded and without holes, crevices, beads or burrs.

Abstract: Centrifugal pump, in particular a hygienic centrifugal pump, provided with a primary and a secondary shaft seal (7,8) at the rear wall (2) of the pump chamber (1). Cooling flushing and barrier fluid is passed to and from a compartment (12) between these seals (7,8), optionally in a flushing fluid circuit. A sensor means (18) is provided in a discharge pipe (16) from the compartment (12) and adapted to measure at least the turbidity, electrical conductivity and temperature of the flushing fluid for activation of an alarm in case of leaking pump fluid through the primary seal (7). As a result the centrifugal pump is more sensitive to leaking pump fluid through the primary seal such that the pump activates an alarm (or optionally shuts down), if the leakage is too extensive.

Abstract: In a valve assembly (1) comprising a pressure medium operated valve (2) and a control unit (5) which is mounted on the end of the actuator (3,4) facing away from the valve (2), the control unit (5) comprises a pressure medium passage (17) having a first end for supplying a pressure medium. The control unit (5) is provided with a coupling (26,27) on the end facing the actuator for releasable connection with coupling members (25) on the actuator (3,4) at axial, non-rotational joining with the actuator (3,4). A second end of the pressure medium passage (17) ends in a branch (20) or opening for pressure medium tight connection with an opening (21) or a branch respectively in the actuator (3,4) at the joining.

Abstract: In order to reduce the requirements for cleaning and provide a structure which is also easy to disassemble for cleaning without the use of tools, a pump, which has a rotary element such as an impeller shaft, is provided with a seal which is arranged so that an annular seal element, such as an O-ring, is disposed in an annular chamber which is sufficiently elongate to allow for a small amount of reciprocal movement of the seal element therein. The movement of the seal member promotes a self-cleaning action which obviates the build-up of particulate material in the annular chamber.

Abstract: A centrifugal pump provided with an impeller, a pump shaft, a pump housing and with a motor coupled to the pump shaft. A shaft seal device is arranged between the pump shaft and the rear wall of the pump housing respectively, and a cooling unit mounted on the outer surface of the latter at the location where the shaft extends through a hole in the rear wall. The shaft seal device is provided with a first set of sealing element arranged between the rear wall and the pump shaft as well as with a second set of sealing element arranged so as to prevent coolant from leaking between the shaft and the cooling unit. A thrust collar is interconnected with a flush pipe extending inside the collar but around the pump shaft and further arranged under the two sets of sealing element. Coolant can flow on the inner surface as well as on the outer surface of the flush pipe. A particularly efficient seal is provided at the location in the rear wall where the extends therethrough.