April 14, 2016 - 5:52 PM EDT
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Patent Issued for Method for the Pressure Regulation of a Barrier Fluid and a Pumping Device for a Method of This Kind (USPTO 9303654)

By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventor Felix, Thomas (Zumikon, CH), filed on April 25, 2008, was published online on April 5, 2016.

The assignee for this patent, patent number 9303654, is Sulzer Management AG (Winterthur, CH).

Reporters obtained the following quote from the background information supplied by the inventors: "The invention relates to a method for the pressure regulation of a barrier fluid in a pumping device in accordance with the pre-characterising part of the claims herein and a pumping device for a method of this kind in accordance with the pre-characterising part of the claims herein.

"Pumping devices for pumping media such as fluids for example, as a rule include a pump unit with a shaft and with a pump housing and a drive unit which is mechanically coupled to the pump unit and also a shaft sealing arrangement which seals the pump housing relative to the shaft. High demands are made on the shaft sealing arrangement if the pump unit and the drive unit are arranged in a common housing or pressure container. Serious damage can arise at the pumping device if the pumping medium which, depending on the use, can also contain solid material components, contaminates critical parts such as bearings. In a case such as this the entire pumping device may often have to be over-hauled. For this reason the common housing or the pressure container is normally filled with a barrier fluid and a pressure regulating system ensures that the pressure of the barrier fluid in the housing or in the pressure container is higher than the pressure of the pumping medium in the pump unit in order to avoid the pumping medium from escaping into the housing or into the pressure container.

"In current pressure regulating systems such as those used in underwater pumping devices for crude oil, either pressure/volume compensators are used or electro-hydraulic pressure valves. The use of pressure/volume compensators results in a comparatively complicated pressure regulating system with a correspondingly large number of components and connections. Furthermore, pressure/volume compensators contain elastic partition walls which are vulnerable to material fatigue. If electro-hydraulic pressure valves are used, an electronic pressure sensor and control is necessary and delays in the reaction time of the pressure regulation system result."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventor's summary information for this patent: "It is the object of the invention to make available a method for the pressure regulation of a barrier fluid in a pumping device and also a pumping device for a method of this kind with which it can be ensured that the pressure of the barrier fluid is higher than the pressure of the pumping medium in the pump unit and which are simply and reliably built, manage with a few components for the pressure regulation and which have a comparatively short reaction time.

"This object is satisfied by the method defined herein and by the pumping device defined herein.

"In the method in accordance with the invention for the pressure regulation of a barrier fluid in a pumping device a pumping medium is pumped by the pumping device. To this end the pumping device includes a pump unit with a shaft and a pump housing, a drive unit, which is mechanically coupled to the pump unit and a shaft sealing arrangement, which seals the pump housing relative to the shaft. In the method, the barrier fluid is conveyed via a feed line to the shaft sealing arrangement and/or to a common housing, in which the pump unit and the drive unit are arranged, in order to prevent a leakage of the pumping medium out of the pump housing. In addition, the pressure of the supplied barrier fluid is increased when a pressure difference between the pressure of the supplied barrier fluid and a detected pressure of the pumping medium in the pump unit falls below a pre-determined value and to this end a differential pressure reducing valve is opened and the feed line is connected through to a source for the barrier fluid via the open valve, with the pressure of the barrier fluid lying above the pressure of the pumping medium in the pump unit. Its pressure advantageously lies above the pressure of the pumping medium in the pump unit by more than the pre-determined value. In an advantageous variant the valve is closed again when the pressure difference between the pressure of the supplied barrier fluid and the determined value of the pumping medium in the pump unit increases above a further predetermined value or the predetermined value.

"In a further advantageous variant the pressure of the supplied barrier fluid is additionally lowered when a pressure difference between the pressure of the supplied barrier fluid and the detected pressure of the pumping medium in the pump unit exceeds a second predetermined value. To this end a differential pressure overflow valve is opened and barrier fluid is discharged via the opened valve, in particular via a connection line to the pump housing or via a return or a discharge for the barrier fluid. This second valve is advantageously closed again when the pressure difference between the pressure of the supplied barrier fluid and the detected pressure of the pumping medium in the pump unit lies below a further predetermined value or below the second predetermined value.

"In a further advantageous variant heat is additionally removed from the pumping device, in particular heat of the drive unit, by circulating the barrier fluid in a cooling circuit with a heat exchanger.

"The pumping device in accordance with the invention for the pumping of a pumping medium includes a pump unit with a shaft and a pump housing, a drive unit which is mechanically coupled to the pump unit, a shaft sealing arrangement which seals the pump housing relative to the shaft and a regulating system for the pressure regulation of a barrier fluid. The regulation system includes a source for a pressurised barrier fluid, which is connected via a feed line to the shaft sealing arrangement and/or to a common housing in which the pump unit and the drive unit are arranged, in order to supply barrier fluid and to prevent a leakage of the pumping medium from the pump housing. The regulating system additionally contains a pressure reducing valve for the differential pressure, which is arranged in the feed line, wherein the valve opens when a pressure difference prevailing at the valve between the pressure of the supplied barrier fluid and a determined pressure of the pumping medium in the pump unit falls below a pre-determined value, in order to raise the pressure of the supplied barrier fluid, and wherein the valve closes again as required when the pressure difference prevailing at the valve exceeds a further predetermined value or the predetermined value. The source or the reservoir is advantageously designed in such a way that the pressure of the barrier fluid made available from it lies more than the predetermined value above the pressure of the pumping medium in the pump unit.

"In an advantageous variant the regulating system additionally contains a differential pressure overflow valve. This second valve opens when the pressure difference prevailing at this valve between the pressure of the supplied barrier fluid and a detected pressure of the pumping medium in the pump unit exceeds a second pre-determined value and this second valve closes again when required when the pressure difference prevailing at this valve exceeds a further predetermined value or the second predetermined value.

"In a further advantageous embodiment the regulating system additionally contains a cooling circuit with a heat exchanger for the barrier fluid, in order take away heat from the pumping device such as, for example, heat of the drive unit.

"In an advantageous embodiment the pressure valve or, if two pressure valves are used, each of the pressure valves has a control inlet for detecting pressure, which is connected to the pump unit in order to detect the pressure inside the pump unit, and an inlet and an outlet for the barrier fluid, wherein the inlet of the pressure reducing valve for the differential pressure is occasionally connected to a first part of the feed line for the pressurised barrier fluid, and the outlet of the differential pressure overflow valve and the inlet of the differential pressure overflow valve are each connected occasionally to a second part of the feed line and the outlet of the differential pressure overflow valve is connected occasionally to a second part of the connection line, which is connected to the pump housing or to a return line or a drain for the barrier fluid.

"In a further advantageous embodiment the regulating system additionally contains one or more of the following components: a storage container for barrier fluid, a pump in order to increase the pressure of the barrier fluid, a reservoir for the pressurised barrier fluid, a circulating pump in order to circulate barrier fluid in a cooling circuit, a check valve in order to prevent the back flow of barrier fluid into the storage container and/or the reservoir and/or in order to prevent the back flow of pumping medium into the regulating system.

"In an advantageous embodiment of the pumping device, this includes a common housing in which the pump unit and the drive unit are arranged, for example a housing which is formed as a pressure container.

"The method according to the invention for the pressure regulation of a barrier fluid and the pumping device in accordance with the invention have the advantage that in order to maintain a desired pressure difference between the pressure of the supplied barrier fluid and the pressure of the pumping medium in the pump unit, only two pressure valves are required, which reduces the number of the components needed for the regulation of the pressure to a minimum. Furthermore, the pressure valves are directly activated by the pressure difference between the pressure of the supplied barrier fluid and the pressure of the pumping medium in the pump unit, as a result of which the reaction time of the pressure regulation can be kept short. It is also advantageous that the passive state of the pressure valves is determined by a spring, as a result of which in the event of a breakdown a clear behaviour of the valves is ensured. Due to the purely hydraulic coupling, signal transmission errors, such as can occur in electronic pressure regulation systems, are ruled out. The method in accordance with the invention for pressure regulation and the pumping device in accordance with the invention thus possess a high degree of reliability since only a few, exclusively mechanical components are required for the pressure regulation.

"The above description of embodiments and variants merely serves as an example. Further advantageous embodiments are documented by the dependent claims and the drawing. Furthermore, within the scope of the present invention, individual features of the described or illustrated embodiments and variants can also be combined with one another to form new embodiments."

For more information, see this patent: Felix, Thomas. Method for the Pressure Regulation of a Barrier Fluid and a Pumping Device for a Method of This Kind. U.S. Patent Number 9303654, filed April 25, 2008, and published online on April 5, 2016. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9303654.PN.&OS=PN/9303654RS=PN/9303654

Keywords for this news article include: Sulzer Management AG.

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Source: Equities.com News (April 14, 2016 - 5:52 PM EDT)

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