CS241436B1 - Chemical submersible pump - Google Patents

Abstract

The chemical submersible pump is designed for pumping chemicals from transport containers or barrels. The issue of universal chemical resistance is solved by a glandless system together with a long thin shaft guide. The pump, consisting of a hollow body (1) with a suction opening (15) and a discharge opening (16) and a coaxially placed guide tube (2), 8 foot bearings (5), guide (7) and head (6) for guiding the shaft (4) with an axial impeller (3) at the lower end and a mechanical coupling (T4) at the upper end, has an overflow tube (8) connected above the head bearing (6), which opens into the pump suction area through an overflow hole (li7). Part of the pumped chemical is returned through the overflow hole (17), which penetrates the bearings (5), (6), (7) and lubricates and cools the sliding surfaces. This arrangement, together with the design of the shaft (4) and the guide bearing (7) made of metal protected by a layer of chemically resistant plastic, which prevents local overheating of the plastic materials rubbing against each other, ensures the pump function without contact of metal parts with the pumped chemical. From a manufacturing point of view, it is advantageous to design the guide bearing (7) in the shape of a helix.

Description

The invention relates to a chemical submersible pump for transferring chemicals from transport containers and solves the problem of universal chemical resistance, a pump by a seal-less system together with a long thin shaft guide.

Current pumps of a similar design are designed primarily with a mechanical seal. The long thin shaft is guided in several plain bearings; located in the guide tube.

These bearings are separated by spacers.

The lubrication is ensured by a permanent grease filling. Between the discharge side of the used axial propeller and the guide tube, a shaft seal, usually ceramic-graphite, is installed on the shaft, which also has the function of a foot bearing. The mutual pressure of both rings is provided by a metal spring. Since there is some intersection of the chemical being pumped when the pump is stationary, the lower end of the shaft, together with the spring, is made of a metal chemically highly resistant material, the choice of which depends on the chemical being pumped. Therefore, a pump of one embodiment is only suitable for pumping a limited type of chemicals due to the different chemical resistance of the modification of the metallic materials used, i.e. the universality of use is lacking. Another disadvantage is the need to flush the pumps after use with clean water, which must then be neutralized. In addition, the pumps must not be placed in the pumped chemical for a long time. From the manufacturing point of view, it is difficult to connect two different shaft materials and another disadvantage is the high cost of special metal materials and gland.

The above mentioned drawbacks are largely eliminated by the chemical submersible pump according to the invention, which is based on the fact that the metal shaft protected by the chemically resistant plastic is guided in the guide tube between the heel and the head bearing by a helical bearing of metallic material provided with

241 436 - 2 - a layer of chemically resistant plastic, the foot and head bearing being selected to allow a portion of the chemical to be pumped through the guide tube to lubricate and cool the sliding surfaces and return to the space after gravity through the head bearing pump suction.

F

Said embodiment provides sufficient lubrication and cooling of the sliding parts and the metal shaft together with the metal guide of the guide bearing ensures, in cases of local friction, heat dissipation to the colder parts of the shaft and guide bearing so as not to overheat the protective plastic locally. This allows the use of the friction of the plastics without the contact of the metallic materials with the pumped chemical.

The attached figure shows a cross-section of a chemical submersible pump according to the invention.

The pump consists of a housing 8 with a suction opening 15 and a discharge opening 16 of the guide tube 2, which together with the discharge tube 8 terminated by the overflow opening 64, form a unit. In the guide tube 2 the foot bearing 2 is elastically fixed by means of a ring 9. A helical guide bearing 1, which is formed by a metal helix protected by a layer of chemically resistant plastic, is fixed above the 3®. The pitch and pitch of the helix runs are selected with regard to the permissible curvature of the protective plastic. Above the guide bearing 3, a head bearing 4 is pressed, which, like the foot bearing 2, is provided with a recess to allow the partially pumped chemical to flow through the guide tube 21. A metal shaft 4 protected by a layer of chemically resistant plastic passes through the bearing tube 2. An axial propeller 3 is mounted thereon. In this case, the mounting height of the head bearing 6 is selected such that, even when the pump displacement is completely closed, a part of the pumped chemical does not rise to the washer ring 60, which together with the labyrinth plate 44 after which the body 6 is vented. Axial forces from the propeller 3 engage the bearing 43 and the torque is transmitted by the mechanical clutch 14.

Design of pump made of polypropylene, bearings made of polytetrafluoroethylene and shaft protection tube made of polyethylene or

Other modifications of polytetrafluoroethylene allow the use of revolutions above 8000 rpm for a body diameter of 40 mm and a length of 1000 to 1700 mm. When pumping the axial propeller 3, it draws the chemical through the suction opening 15 in the body 11 from the container and pushes it through the space between the body 6 and the guide tube 2 through the discharge opening 16. In doing so, some of the pumped chemical penetrates into the guide tube 2 where it lubricates and cools the sliding surfaces. via the shaft 4 and the bearings 2 ^{and above the} head bearing 6, it returns via the discharge tube 8 under gravity to the pump suction area through the overflow opening 17.

Another advantage of this pump is the simple assembly of a single pump; guide bearings compared to several bearings for existing pumps. The metal wire with the plastic protective layer is wound into a helical shape with a diameter about 0.5 mm larger than the guide tube diameter and is drawn into the tube before the mounting of the foot and head bearing. This eliminates the need for lubrication in comparison with existing pumps.

The use of this pump can be extended to the handling of petroleum products or other fluids without mechanical impurities transported in drums, etc.

Claims (2)

SUBJECT OF THE INVENTION 241 436 Chemical submersible pump consisting of a hollow body with a suction port at the bottom and a discharge port at the top, with a guide tube with a foot and head bearing for shaft mounting coaxially fixed inside the body, with an axial propeller mounted at its lower end and an upper end a mechanical clutch (characterized in that the metal shaft (4) coated with chemically resistant plastic) is guided in the space between the foot bearing (5) and the head bearing (6) by a guide bearing (7) formed of a helix of metal material provided with a chemically resistant plastic layer. Chemical submersible pump according to claim 1, characterized in that the bearings (5), (6) are provided with a recess for allowing a portion of the pumped chemical to flow through the guide tube (2).