NO147798B - HOMOGENIC, WATERY, BUILDING DETERGENT MIXTURE. - Google Patents

Description

Device with fully enclosed centrifugal pump for aggressive and/or easily boiling liquids.

In the chemical industry and in refrigeration technology, you are faced with the problem of leaks in the liquid circuit. One of the most difficult points is at the pump packing box. In cooling systems, pumps are mostly used in so-called low-pressure circulation systems, where leaks can mean a large economic loss in addition to the harmful effect that the outflowing medium can cause.

To avoid such leaks, one has

introduced so-called fully enclosed pumps, as the pump's motor or its rotor is enclosed against the surroundings in the same room as the pump's mechanical parts, whether this is a vane rotor, an impeller for a centrifugal pump or a displacement rotor, as the liquid also serves for the necessary cooling of the motor as well as lubrication of the storage.

These bearings usually have a short lifespan, as the circulating liquid has poor lubricating properties, and the supply of other lubricants (oil, grease) will cause a harmful and unwanted mixture in the circulating liquid.

The poor lubricity of the circulating liquid causes wear on the bearing rings, which means that the motor's rotor does not get the right clearance against the capsule, and ultimately risks abrasive contact with it.

There is also a risk with volatile liquids

a strong vapor formation that makes lubrication of the bearings illusory. The aforementioned conditions easily lead to destruction of both the motor's electrical windings and the bearings themselves. .Ve» The invention relates to pumps of the type that have a partition wall between the pump housing and motor housing, and with a stuffing box for the common continuous vertical shaft. This axle's bearings are located in the engine housing, and where they are lubricated with circulating oil, as the aforementioned stuffing box prevents oil from penetrating the fluid circulation system.

The new and characteristic feature of the invention is that one or more connections are arranged between the inside of the motor housing and the inside of the pump housing, in which valve member is inserted which opens for excess pressure in the motor housing, the motor housing having an oil filling at the bottom with a connection to the axle's storage member and said connection or connections are led out from the inside of the engine housing at a level higher than that of the oil.

The purpose of this new device is that liquid from the system that leaks up through the stuffing box and stored and thus seeps into the engine compartment, due to the heating in the electric motor during operation will be gasified and due to the resulting pressure in the engine compartment will be pushed out through the aforementioned connection or connections . This liquid is thereby returned to the system, at the same time that the oil in the bottom of the engine compartment is constantly regenerated so that it retains its lubricating ability.

A special embodiment of the invention is that the motor housing can be placed under a pre-determined overpressure in relation to the pump housing by means of an inactive gas in order to prevent the circulating liquid from penetrating into the motor housing.

For a better understanding of the invention, it will be described in more detail below with reference to an embodiment shown in the drawing. This reproduces an axial section through a fully enclosed centrifugal pump of the above-mentioned type, in which the invention has come to be used. However, it will be understood that this embodiment is only an example of how the purpose of the invention can be fulfilled and that thus a number of modifications can easily be imagined. Thus, the connection channel between the motor housing and the pump housing can instead be between rooms or parts of the system where it is still connected to the interior of said housing via valve means as mentioned, or be connected to an apparatus in which there is a lower pressure than in the motor housing, which apparatus then can return the gas or liquid leaving the engine housing to the liquid system.

In the drawing, 1 is the motor housing for a fully enclosed centrifugal pump for use e.g. in a refrigeration plant. This motor housing is connected to the pump housing 2, as there is a tight intermediate wall 3 between these two housings. This intermediate wall 3 has a central passage for the vertically extending shaft 6, on the upper end of which the rotor 5 is attached, which cooperates with the stator 4 Between the rotor and the stator there is arranged a cylindrical, tight shield 13 (slit tube motor).

At the bottom of the engine housing, i.e. in the intermediate wall 3, there is arranged a bearing 8 for the axle 6 and a further bearing 8' for this is arranged at the upper end of the sleeve-shaped extension upwards of said intermediate wall 3.

Under the lower bearing 8, there is a stuffing box 7 or other appropriate seal which should best prevent liquid from penetrating along the shaft from the inside of the pump housing 14 into the inside of the motor housing 15. Its lower part is filled with an appropriate lubricating oil which through the openings 17 in the sleeve-shaped extension 18 can flow down to the bearings 8 and lubricate them. At the same time, oil which is inside this extension during the shaft's rotation will also be supplied to the upper bearing 8', possibly accelerated by means of a device not shown.

In the intermediate wall 3, a continuous channel 12 has been taken out, at the upper end of which is sealingly attached, e.g. by screwing in a valve device in the form of a tubular valve housing 10, in which a ball valve is arranged. This opens for excess pressure in the engine compartment and is spring-loaded, e.g. to open at approx. 0.5 kg excess pressure. Thus, if the pressure in the pump's liquid system is 8 kg, said valve 10 will open for a pressure in the motor housing of 8.5 kg. This excess pressure in the engine housing will occur during the operation of the centrifugal pump unit due to the heat developed thereby, since the engine housing is completely sealed against the surroundings.

A filling opening 16 can be arranged in

engine housing for topping up oil.

The level of the oil 9 in the motor housing is somewhat below the top or intake for the valve device 10. When the device is thus in operation, exhaust gas from the motor housing will be pushed out through the valve 10 by the pressure in it and returned to the pump's cavity 14. Waste of expensive coolant is thus completely eliminated at the same time as effective and lasting lubrication of the bearings 8 and 8' for the pump-motor device's common shaft 6 is obtained. The stuffing box 7 prevents oil from being able to penetrate into the pump housing and thus from mixing with the cooling system liquid.

From the above it will be clear that according to the invention a device is provided for fully enclosed centrifugal pumps for e.g. cooling system that offers significant technical and economic advantages compared to previous aggregates of this type.

Claims (1)

Device for fully enclosed centrifugal pumps for aggressive and/or easily boiling liquids consisting of an electric motor housing and a pump housing located below this, which housings are separated by a tight partition provided with a sealing passage for a common motor and pump, verti- bare shaft and where the lower part of the engine housing takes up an amount of oil that lubricates the axle bearings, characterized in that between the interior of the engine housing or the cavity connected to it and the interior of the pump housing or the cavity connected to it, one or more connections (12) are provided with valve means (10) which opens for excess pressure in the engine housing, as the connection or connections' inlet opening is led out above the surface level of the amount of oil in the lower part of the engine housing (9).