Abstract: A conveying device for conveying a liquid/gas mixture, in particular a crude-oil/natural-gas mixture, taken from a borehole, having a multiphase-pumping device, which can be or is coupled to a feed line and a discharge line and to which the liquid/gas mixture can be fed as a feed flow, via the feed line and via which the mixture can be discharged under increased pressure as a conveyance flow, into the discharge line, and having a recirculation line, via which a sub-flow of the liquid contained in the conveyance flow can be returned to the feed flow. The recirculation line contains an injector, through which the sub-flow is conducted, with a negative pressure being generated in the process, and which can be or is coupled to a gas line, which conducts a gas taken from the borehole. The negative pressure causes the gas to be taken in by suction.

Abstract: A conveying device for conveying a liquid/gas mixture, in particular a crude-oil/natural-gas mixture, taken from a borehole, having a multiphase-pumping device, which can be or is coupled to a feed line and a discharge line and to which the liquid/gas mixture can be fed as a feed flow, via the feed line and via which the mixture can be discharged under increased pressure as a conveyance flow, into the discharge line, and having a recirculation line, via which a sub-flow of the liquid contained in the conveyance flow can be returned to the feed flow. The recirculation line contains an injector, through which the sub-flow is conducted, with a negative pressure being generated in the process, and which can be or is coupled to a gas line, which conducts a gas taken from the borehole. The negative pressure causes the gas to be taken in by suction.

Abstract: A method for conveying a fluid through a screw pump, wherein at least one drive spindle of the screw pump is driven by an asynchronous motor, wherein, the asynchronous motor is operated at a first nominal frequency, a gas/liquid mixture being conveyed as fluid, a measurable variable depending on a liquid content of the fluid is registered, and after a fulfillment of a frequency-change condition depending on the measurable variable the asynchronous motor is operated at a second nominal frequency, reduced in comparison with the first nominal frequency.

Abstract: A method for determining a flow volume of a fluid delivered by a pump. The flow volume is determined as a function of predefined pump information depending on a pump geometry, rotation speed information, which correlates with the rotation speed of the pump, and pressure information, which correlates with a differential pressure at the pump.

Abstract: Method for delivering a gas/liquid mixture fluid via a screw spindle pump that has a housing in which a drive spindle and a running spindle are accommodated. The spindles delimit together with the housing multiple pump chambers. A respective one of the pump chambers that is initially open toward the respective fluid inlet is closed off. The resulting closed-off pump chamber is moved axially toward the fluid outlet and, there, upon attainment of an opening rotation angle, is opened toward the fluid outlet. The drive spindle is driven so that the pressure in the respective pump chamber prior to and/or upon attainment of the opening rotation angle is increased in relation to the suction pressure of the screw spindle pump by at most 20% or by at most 10% of a difference in pressure between the suction pressure and the pressure in the region of the fluid outlet.

Abstract: A screw pump, including a housing with a running bore having at least two intersecting bores, each of which receives a spindle, wherein the spindles have worm screw profiles which intermesh in portions and in operation bend in a defined bending direction under a hydraulic bending pressure, wherein each bore is configured as a slot with a longer first axis of symmetry and a shorter second axis of symmetry standing orthogonally thereto, wherein the longer first axis of symmetry runs in the bending direction.

Abstract: A method for conveying a fluid through a screw pump, wherein at least one drive spindle of the screw pump is driven by an asynchronous motor, wherein, the asynchronous motor is operated at a first nominal frequency, a gas/liquid mixture being conveyed as fluid, a measurable variable depending on a liquid content of the fluid is registered, and after a fulfillment of a frequency-change condition depending on the measurable variable the asynchronous motor is operated at a second nominal frequency, reduced in comparison with the first nominal frequency.

Abstract: A method for delivering a gas/liquid mixture fluid via a screw spindle pump that has a housing forming at least one fluid inlet and one fluid outlet and in which a drive spindle and a running spindle, coupled in terms of rotation, are accommodated. The spindles, in each rotation position of the drive spindle, delimit together with the housing multiple pump chambers. The drive spindle is rotated by a drive in a drive direction, whereby a respective one of the pump chambers that is initially open toward the respective fluid inlet is closed off. The resulting closed-off pump chamber is moved axially toward the fluid outlet and, there, upon attainment of an opening rotation angle, is opened toward the fluid outlet.

Abstract: A screw pump, including a housing with a running bore having at least two intersecting bores, each of which receives a spindle, wherein the spindles have worm screw profiles which intermesh in portions and in operation bend in a defined bending direction under a hydraulic bending pressure, wherein each bore is configured as a slot with a longer first axis of symmetry and a shorter second axis of symmetry standing orthogonally thereto, wherein the longer first axis of symmetry runs in the bending direction.

Abstract: A method for determining a flow volume of a fluid delivered by a pump, wherein the flow volume is determined as a function of predefined pump information depending on a pump geometry, rotation speed information, which correlates with the rotation speed of the pump, and pressure information, which correlates with a differential pressure at the pump.