Evaporator Film Former

Abstract

Evaporators used in radiochemical production designed to evaporate highly active solutions and devices designed to create thin film in the heating chambers.

The film former contains a liner in the upper part of the heat exchange tube attached to the spindle of the bellows assembly of the evaporator lid. The liner is provided with a radiation-proof tip that is not wettable by liquid being evaporated. The tip is made of two conjugate cones: the upper back cone and lower right cone, with the lower cone having a cylindrical belt with protrusions on it designed to center the conical tip on the inner surface of the heat exchange tube. A cap is mounted movably on the liner, with grooves on the lower end of the cap along the entire perimeter.

The liner attached to the spindle is connected by fins with adjacent liners installed in heat exchange tubes.

Claims

1. An evaporator film former comprising a liner and a cap, which are installed in the upper part of the heat exchange pipe located between the tube plates in the evaporator housing with a lid, characterized in that the liner is attached to the spindle of the bellows assembly installed on the evaporator lid with a possibility to be remotely controlled and provided with a tip made of radiation-resistant material not wetted by the evaporated liquid; the tip being made of two conjugate cones: the upper back cone and the lower right cone, with the lower cone being provided with a cylindrical band with projections, which are designed to center the conical tip along the inner surface of the heat exchange tube, and a movable cap is mounted on the liner, and the lower end of the cap is provided with grooves along its entire perimeter.

2. Film former according to claim 1, characterized in that in the liner along its axis, there is a hole communicating with the space above the tube plate higher than the level of the evaporated liquid on it.

3. Film former according to claim 1, characterized in that the liner connected to the spindle of the bellows assembly is connected by fins with adjacent liners installed in heat exchange tubes and provided with conical tips and caps.

4. Film former according to claim 1, characterized in that the remote control of the bellows assembly mounted on the evaporator lid may be performed by a manipulator or by connecting the bellows assembly to an actuator using a rod.

Description

BRIEF DESCRIBTION OF THE DRAWINGS

[0031] The invention is illustrated in the drawings represented in FIG. 1, FIG. 2 and FIG. 3.

[0032] FIG. 1 shows the proposed film former with a joint output of the steamed off solution and secondary steam in the section;

[0033] FIG. 2 shows the proposed film former in the section with a separate output of one steamed off solution and secondary steam in the section;

[0034] FIG. 3 shows the proposed film former with the regulation of the thickness of the film of liquid flowing through several heat exchange tubes.

DETAILED DESCRIPTION

[0035] The proposed film former (see FIG. 1) contains a bellows assembly 2 hermetically installed in the evaporator lid 1, which is used in bellows valves, and connected with actuator 4 through rod 3.

[0036] Spindle 5 of the bellows assembly 2 is connected wit liner 6 that is mounted in the upper part of the heat exchange tube 7 attached to the tube plate 8. Liner 6 is provided with tip 9 made of a material that is not wettable by liquid being evaporated. When evaporating highly active solutions, tip 9 is made of radiation resistant material. Tip 9 is made in the form of two conjugate cones: the upper back cone 10 and the lower right cone 11. The lower cone 11 is provided with a cylindrical band 12 fitted with protrusions 13, which center tip 9 on the inner surface of the heat exchange tube 7. Cap 14 is mounted movably on liner 6, grooves 15 being made on the lower end of the cap along the entire perimeter.

[0037] There may be hole 16 done in liner 6 (see FIG. 2), which is connected to radial holes 17 located above the level of the evaporated liquid on the tube plate 8.

[0038] By means of fins 18, liner 6 connected to spindle 5 of the bellows assembly 2 can be connected (see FIG. 3) with adjacent liners 6 equipped with tips 9. Adjustable gap 19 is formed between back cone 10 of tip 9 and the end of heat exchange tube 7.

[0039] When using the proposed device in the evaporator (remote heating chamber) used in conjunction with the separator (not shown in the drawings), the secondary steam and the steamed off solution enter the separator together and are separated there. In this case, holes 16 and 17 in liners 6 are not performed.

[0040] The claimed device operates as follows.

[0041] The evaporated liquid is supplied to the tube plate 8 and forms a layer of a certain height on it, the hydraulic pressure of which provides the flow of fluid through grooves 15 located along the perimeter of cap 14 into the annular gap between cap 14 and tip 9 of liner 6. This ensures uniform distribution of the fluid throughout the entire area of the annular gap between cap 14 and reverse cone 10 of tip 9. Then the liquid enters the adjustable gap 19 between the upper end of the heat exchange pipe 7 and the back cone 10 of tip 9. By moving spindle 5 of the bellows assembly 2 with the help of the manipulator (not shown) or actuator 4, the flow area of the adjustable gap 19 is changed and the flow rate of the fluid flowing through gap 19 is set to form a film that flows uniformly and stably through the heat exchange tube 7.

[0042] If a part of the liquid will flow down the back cone 10, then the lower right cone 11 will redirect it to the heat exchange tube 7. The liquid film flows then along the gap between the heat exchange tube 7 and the cylindrical band 12 of the right cone 11.

[0043] Film that flows in places of contact of the projections 13 with the heat exchange tube 7 will bend around them and close under the projections 13 due to the non-wettability of the material, which tip 9 is made of. The liquid gest evaporated intensively while flowing down as a film along the heat exchange tube 7. From the central part of the heat exchange pipe 7 through holes 16 and 17, the resulting secondary steam rises into the space under lid 1 above the level of the liquid on the tube plate 8 and is removed from the evaporator.

[0044] In the case of application for the separation of the steamed off solution and the separator's secondary steam, the steamed off solution and the resulting secondary steam from the evaporator are output together to it. In the vacuumized separator, the secondary steam is additionally released from the heated streamed off solution.