Abstract: A multistage centrifugal pump has a foot part (2) and a head part (9), between which pump stages are integrated. The head part (9) and the foot part (2) are connected via tie-rods (11) which with one end are fastened on the head part (9) and with the other end are fastened on the foot part (2). The tie-rods (11) at one end comprise a thread (14), with which they are tightened on the head part (9). The tie-rods (11) are formed from sheet metal. At the end opposite the thread, the tie-rods include a recess, with which recess the tie-rods are each positively fixed on the foot part (2), at least in the tensile direction (22).

Abstract: A multistage centrifugal pump with a foot part (2) and with a head part (9), between which pump stages are integrated. The head part (9) and the foot part (2) are connected via tie-rods (11) which with one end are fastened on the head part (9) and with the other end are fastened on the foot part (2). The tie-rods (11) at one end comprise a thread (14), with which they are tightened on the head part (9).

Abstract: The method serves the commutation of an electrically commutated brushless, polyphase permanent magnet motor. The commutation angle, i.e. the angle from the zero crossing of the BEMF signal up to the reapplication of the voltage to the same winding is determined by the angle which results when the winding phase current has reached zero until the zero crossing of the BEMF signal.

Abstract: The method serves the commutation of an electrically commutated brushless, polyphase permanent magnet motor. The commutation angle, i.e. the angle from the zero crossing of the BEMF signal up to the reapplication of the voltage to the same winding is determined by the angle which results when the winding phase current has reached zero until the zero crossing of the BEMF signal.

Abstract: The method serves the commutation of an electrically commutated brushless, polyphase permanent magnet motor. The commutation angle, i.e. the angle from the zero crossing of the BEMF signal up to the reapplication of the voltage to the same winding is determined by the angle which results when the winding phase current has reached zero until the zero crossing of the BEMF signal.

Abstract: A device for the external cooling of the electrical drive motor of a centrifugal pump unit, which with the motor is advantageously to be assembled above the centrifugal pump, comprises a hermetically closed hollow body of heat-conducting material which circumferentially at least partly surrounds the motor and which with its wall surface on the motor side and on the pump side is in heat-conducting surface contact with the motor and the centrifugal pump, wherein the hollow body is essentially filled with a fluid which transfers the motor heat and which, with a heated motor, is subject to a natural circular convection flow.

Abstract: The centrifugal pump unit includes a flow switch arranged within the pump housing in the flow path of a delivery fluid, which essentially consists of an electromagnetic switch device and a two-armed, pivotably mounted lever whose one arm projects into the flow path and whose other arm carries a magnet which is in contact-free active connection with the switch device. The switch device is arranged within a terminal box mounted on the unit housing. The lever is seated within a switch housing which is incorporated in a cartridge-like manner into the pump housing and which is hermetically sealed to the outside and which is arranged neighbouring the terminal box that such it is only in magnetic active connection so that the reed contact located in the terminal box is controlled by the magnet located in the switch housing. In this manner a usual terminal box may be used which does not need to be sealed with respect to the delivery flow.

Abstract: The method for controlling a voltage/frequency converter controlled single-phase or polyphase electric motor evaluates the phase shifting between the EMF and BEMF by way of the deviation between the zero crossing of the phase current and the voltage produced by the intrinsic induction and readjusts the frequency of the converter accordingly. The measurement of the intrinsic induction is effected in the zero crossing of the current courses of the associated phase, wherein during the measurement the phase is separated from the supply network.

Abstract: The wet-running submersible motor comprises a shaft and an electrical rotor arranged thereon, both being arranged in the rotor space of the motor. The shaft is formed hollow either on its longitudinal section on the pump side or over the whole length. On the pump side the shaft surrounds a sealing formation for sealing the rotor space of the motor with respect to the pump. Furthermore the hollow shaft is provided with radial flow passages in order to circulate fluid in the rotor space of the motor. Through the hollow shaft fluid is also led to the pump side, for which the shaft end on the pump side is provided with a fluid passable functional unit. The functional unit is formed so that it at least allows a fluid flow towards the pump side in order to bleed the rotor space and to reduce excess pressure in the rotor space which is subsequently filled with delivery fluid via the sealing formation, by way of fluid exit towards the pump side.

Abstract: The invention relates to a pressure or differential pressure sensor comprising a membrane with at least one measuring element located thereon, as well evaluation electronics for measuring the membrane deflection. The membrane is covered against environmental influences with a protective layer and is gripped within a mounting in a pressure tight manner. The protective layer is composed of a fluid tight amorphous metal layer, a so called metal glass layer which with the interposing of an electrically insulating layer, is directly deposited onto the membrane, the measuring element located thereon and where appropriate, onto further electronic components located thereon. In this manner, on the one hand, the membrane is protected but on the other hand it may be deflected sensitively since the amorphous metal layer is fluid and gas tight even with layer thicknesses in the .mu.m region.

Abstract: The invention relates to an electronic component manufactured in thick film technology, thin film technology or silicon technology and then provided with an electrically insulating layer which is covered by an amorphous metal layer. The amorphous metal layer protects the component, even with the smallest of layer thicknesses, from external influences and directly transmits heating and force effects.

Abstract: A submersible motor unit comprises an electrical drive motor, an electrical control means for setting the rotary speed and/or the torque of the motor, a common heat-conducting housing for the motor and the control means as well as a connection cable electrically connected to the control means wherein this means is provided on the end side of the motor distant to the pump. In particular for an improved disposal, repair and cooling of the submersible motor unit the electrical control means is formed as a cartridge-like constructional unit which can be inserted into the common housing and which can be electrically plug connected to the drive motor, and the housing of the control means connected to the unshielded connection cable bears with its outer circumferential surface on the inner circumferential surface of the common housing.

Abstract: A sensing device for measuring temperature and pressure of a fluid medium in a pump housing. The device includes a common housing for containing a temperature sensor and a differential pressure sensor. The housing includes a temperature-sensor housing portion and a pressure-sensor housing portion disposed along a common axis. The temperature-sensor housing portion has a substantially cylindrically shaped projection configured for insertion into a corresponding bore in the pump housing and which sealingly encapsulates the temperature sensor therewithin. The projection has pressure measurement apertures defined in its side wall near the free end of the projection for communicating fluid pressures in the pump housing to the differential pressure sensor which is sealingly enclosed within the pressure-sensor housing portion.

Abstract: A submersible motor for driving a centrifugal pump. The motor includes a rotor space filled with a fluid and the rotor space on the pump side is sealed by way of a sealing formation penetrated by the motor shaft which carries the rotor of the motor. In the rotor space between the sealing formation and the rotor there is provided a stationary separating wall, letting through the motor shaft, for forming a smoothing space in front of the sealing formation.

Abstract: An inline centrifugal pump comprising a radial or semiaxial impeller. The rotational axis of the impeller is perpendicular to the flow axis of the connection pieces. A suction channel leading from the suction connection of the pump housing to the suction mouth of the impeller comprises, in the turning region, a conically tapering section which runs towards the suction mouth of the impeller. In this manner the efficiency of the pump can be improved.

Abstract: The invention relates to a frequency converter supplied electric motor comprising a cooling air blower, the cooling air of which for cooling the motor is guided along cooling ribs which are arranged on the motor housing. The frequency converter is arranged in a housing which is detachably connected to the motor housing and which comprises a first heat conducting housing part and at least a further housing part. The first housing part of the frequency converter housing forms the fan cowl and comprises a transverse wall which is provided and formed for the heat conducting connection to the heat producing components of the power circuit of the frequency converter. The first housing part is formed ribbed and openings in the hosing wall are provided in the footwell of the cooling ribs as air inlet openings for the cooling air stream. Moreover there is provided a further housing part which connects to the first housing part and has a purely accomodating function.