Device for removing fluid from a container

#The invention relates to a device for removing fluid from a container which holds gas and which has, in the area of a collecting point for fluid, an extraction connection which may be connected to a collecting container by way of an extraction line, which container may be connected by way of a compensating line to a compensating connection mounted on the container, which compensating connection is different from the extraction connection.

#When containers holding gas are used in hydraulic circuits, oil is regularly fed to the gas side of the container, and accordingly fouling with oil occurs on the gas side. The fluid involved may also to some extent include an abrasive substance such as one deriving from movable rubber seals or the like. In addition, the fluid is regularly displaced by the operating gas. If it is desired to extract the fluid in question from the container, one in the form of a piston-type accumulator, for example, especially from the gas side of the container, the entire hydraulic system generally has to be shut down for a lengthy period, or at least the part of the system including the piston-type accumulator to be serviced and to be cleaned. In addition to the protracted system downtime, precise safety regulations must be adhered to, something which on the whole makes the servicing process elaborate and cost-intensive. The conventional servicing equipment, which optionally allows refilling of the gas side of the container with an operating gas, is structurally bulky and difficult to handle.

#DE 297 22 504 U discloses a container for gaseous media, especially a large-volume pipeline with an inlet connection and an outlet connection, and with a vent connection and drain connection, the inlet connection and the outlet connection being designed simultaneously as vent and drain connections. The inlet connection comprises two inlet pipes which lead from a side inlet connection of the container in an arc to a high point in the interior of the container, the outlet connection comprising two outlet pipes which extend from a low point in the interior of the container in an arc to a side outlet connection of the container. Conventional containers, generally in the form of large-volume pipelines, are usually classified by general regulations as systems requiring monitoring, ones which are subject to strength and tightness testing with water, identified by the term water pressure testing, before being placed in service.

#In the drawing, the following are represented in principle and not according to scale:

#FIG. 1 a connection plan of the device showing it in connection with a floating piston reservoir;

#FIG. 2 a partial representation of a cross section through a nitrogen reservoir with its connections for the connection of the liquid removal device as shown in FIG. 1.

#The device shown in FIG. 1 serves for the removal of liquid, especially removal of oil used for hydraulic power, from a container 10, which also contains a gas, especially in the form of gaseous nitrogen. In the area of a collection point 12 for the liquid which is to be replaced with the working gas and therefore is present in foamed condition is located a removal connection 14, to which can be connected a collection container 18 through a removal conduit 16, which container 18 in turn can be connected through an equalization conduit 20 with an equalization connection 22 arranged on container 10, which connection 22 is different from the aforementioned removal connection 14. The container shown in FIG. 1 represents what is termed a hydraulic reservoir in the form of a floating piston reservoir with a separating element, not shown, which in this case separates the liquid side 24 from the gas side 26 of the container in a traditional manner, for which purpose the floating piston reservoir and consequently container 10 is held in horizontal alignment in such a manner that removal connection 14 opens in the cover 28 of container 10 on its gas side 26, and actually in the lowest area, in other words at the bottommost point of the reservoir.

#Removal connection 14 is particularly configured as a sort of a tap line, which engages through cover 28 and then bends downward at a right angle as seen in FIG. 1 and there opens in gas side 26. By this means it is guaranteed that with horizontal alignment of the structure the liquid removal process takes place effectively at the bottommost point of container 10, whereby the liquid in the form of hydraulic oil is precipitated downward by the force of gravity and collects at the collection point 12. An O-ring gasket is arranged in cover 28 between the bending downward of tap-like removal connection 14 and the surrounding environment, where the O-ring seals cover 28 from the interior of the housing of container 10. Insofar as the oil removal device is being used with a floating piston reservoir, oil passes continuously in any case from liquid side 24 through the gaskets of the separating element, not shown, to gas side 26 and consequently leads to contamination of the working gas with the liquid. The liquid too can be contaminated by the abrasion material in the packing in the form of a gasket on the separating element. Furthermore the fluid being precipitated at collection point 12 is being replaced with the working gas and therefore is present in foamed condition. Removal connection 14 is to be introduced into cover 28 on the production side, whereby the resulting additional outlay for construction is low. An equalization connection 22 on the other hand is present with each container 10, since it generally serves for the refilling of the working gas, insofar as this gas for example in the case of a floating piston reservoir passes through the gasket system of the separating element to the liquid side 24 of the reservoir. Consequently a connection which is already present on the container side is used for equalization connection 22, so that no further costs are generated as a result of further construction.

#On the bottom of collection container 18 is found a shut-off valve 30 which allows the fluid precipitated in collection container 18 if necessary together with the contaminants to be discharged from collection container 18. At the top of collection container 18 is connected a valve device indicated in its entirety as 32 and including a first spring-biased check valve 34 between removal conduit 16 and collection container 18 as well as a second spring-biased check valve 36 between container 18 and equalization conduit 20. With this arrangement, the direction of opening of first check valve 34 is in the direction of collection container 18 and the direction of opening of second check valve 36 is away from collection container 18 in the direction of equalization conduit 20. Furthermore in equalization conduit 20 between collection container 18 and container 10 is connected a filling and testing device which is indicated in its entirety as 38, which is actually preferably located directly on equalization connection 22 of container 10. This filling and testing device 38 is not absolutely necessary, but makes the process of liquid removal from the container more secure and more convenient for the operator.