RU2427413C1 - Centrifugal edge filter - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to filtration, namely, to cartridge filters intended for purification of acid solutions in radiochemical and other industries. Proposed filter comprises vertical housing consisting top cylindrical section, bottom section made up of inverted truncated cone, top cover and bottom cover with fluid feed branch pipe, coaxial filtration cartridge with regularly arranged cutouts, shield, flow swirler made up of vanes fitted fixed on shield and provided with face taper slopes, nozzle with inlet bell jointed to housing bottom cover and provided with peripheral slots while outlet bell features inclination equal to that vane tape slope. Nozzle and housing taper wall form annular receiving chamber. Nozzle inlet bell is centered at annular grooved made in housing bottom cover. ^ EFFECT: higher efficiency, longer life of filtration cartridge, simplified design. ^ 2 cl, 1 dwg

Description

The invention relates to filtering, and in particular to cartridge filters designed for the purification of acidic solutions in radiochemical and other industries.

Obtained in the process of dissolution, the nitric acid solution of nuclear fuel is sent to extraction processing for the purpose of purification and separation. However, the presence in the solution of needle-like substances with a tendency to adhesion of under-dissolved substances causes various disturbances both during preparation and during extraction cleaning. To ensure the smooth operation of the equipment, the solution must first be cleaned of undissolved impurities.

Known pulsating filter-thickeners continuous action (V.I. Zemlyanukhin, E.I. Ilyenko and others. "Radiochemical processing of nuclear fuel of nuclear power plants", M., Energoizdat, 1989, p. 73). The imposition of pulsations on the initial suspension supplied to the filter avoids the accumulation of a large layer of sediment on the filter surface, and the periodic supply of a pulse in the opposite direction to the filter allows the filter partition to be regenerated. The filtering rate is almost unchanged. The disadvantage of these devices is the formation of additional volumes of highly active discharges during the regeneration of filters.

A device for the separation of aggressive media, containing a cylindrical body, inside which is a separating element made of coaxially mounted pipes forming uniform annular slots (AS USSR No. 570378, publ. 30.08.1977).

The disadvantage of this device is the inability to catch needle-like components of undissolved impurities, the passage of which leads to the output of the shut-off pipe fittings from a healthy state.

Known slotted filter cartridge (US Pat. RF No. 2196631, publ. 01.20.2003) containing a cylindrical filter element having uniformly distributed transverse slots and an insert, the perforation of which is made in the form of transverse slots that are offset along the vertical axis relative to the slots of the filter element. The particles of the filter material, having dimensions larger than the dimensions of the filter slots of the cartridge, remain outside the filter element and partially in its slots.

The disadvantages of the slotted filter cartridge are:

- difficulty in manufacturing;

- rapid clogging of the slots of the filter element with solid particles, which leads to a decrease in the performance and service life of the filter.

Closest to the claimed device is a centrifugal slotted filter (US Pat. RF No. 2335329, publ. 10.10.2008), selected for the prototype. The filter contains a housing with a nozzle for supplying a cleaned medium, a nozzle for removing mechanical impurities and a mud chamber, a coaxial filter cartridge that has a tubular shape with longitudinal slots of a certain size. A swirl chamber in the form of a pipe is attached to the filter housing, in which a flow swirler is installed, made of blades mounted on a centering rod of a stepped shape. The flow of the cleaned medium enters the blades, acquires a rotational-translational motion. Due to the centrifugal force, particles of mechanical impurities are thrown to the wall of the filter housing and fall into the branch pipe for removal of mechanical impurities and then into the mud chamber.

The prototype has several disadvantages:

- the location of the blades in the swirl chamber, a stepped fairing, a branch pipe for removing mechanical impurities complicate the design of the device;

- the separation efficiency decreases with distance from the device, swirling the flow due to a decrease in the flow rate of the cleaned liquid;

- this device is unable to transfer the accumulated undissolved substances into the filtered solution, which leads to their loss;

- the horizontal design of the filter, in the event of an emergency stop, will precipitate all mechanical impurities in the solution on the filter element and on the inner surface of the housing, which will significantly reduce the efficiency of the filter as a whole and the ability to trap impurities with adhesive properties, in particular.

The objective of the invention is to develop a filter, which is characterized by a high efficiency of cleaning acidic solutions from undissolved impurities, the possibility of dissolving the collected precipitate, increasing the service life of the filter and simplicity of design.

The problem is solved in that in a slotted centrifugal filter containing a housing with a nozzle for supplying the medium to be cleaned, a coaxial filter cartridge with evenly distributed slots, a cowl, a flow swirl made of blades and a receiving chamber, the vertically located housing consists of an upper cylindrical part, the lower part in the form of an inverted truncated cone, the upper cover and the lower cover, to which a pipe is connected to supply the medium to be cleaned. The swirl blades of the flow are stationary mounted on the fairing and have end conical bevels. The filter further comprises a nozzle, the inlet of which is connected to the bottom cover of the housing and provided with grooves around the perimeter, and the outlet of the nozzle has an inclination angle equal to the angle of inclination of the conical bevels of the blades, while the nozzle and the conical wall of the housing form an annular pocket, which is a receiving chamber.

The nozzle inlet is centered in an annular groove grooved in the lower housing cover.

The drawing shows a General view of the device.

The device comprises a housing 1, consisting of two parts: the upper cylindrical part 2 and the lower part 3, made in the form of an inverted truncated cone. The upper cylindrical part 2 has an upper cover 4. The lower part 3 has a lower cover 5. A pressure nozzle 6 for introducing the solution to be cleaned is connected to the lower cover 5. A coaxially located filter cartridge 7 with evenly distributed slots 8 is fixed in the upper cover 4 and has a cowl 9 made in the form of the tip of the filter cartridge 7. The blades 10 with conical bevels of the ends are stationary mounted at an angle to the horizontal plane on the cowl 9. The lower cover 5 has an annular a groove 11 in which the inlet socket 12 of the nozzle 13 is centered. The nozzle 13 is mounted on the ribs 14 located on the housing 1. For reliable fixation of the nozzle 13, the angles of the conical bevels of the blades 10 are the inclination of the upper bell 15 of the nozzle 13. The absence of welded joints increases the corrosion resistance of the device. The nozzle 13 forms an annular pocket 16 with the housing 1. The inlet 12 of the nozzle 13 is provided with grooves 17 around the perimeter.

The device operates as follows.

The nitric acid solution containing undissolved impurities is fed through the discharge pipe 6 to the nozzle 13, where the flow rate of the solution increases due to the cowling 9. At the same time, the cowling 9 protects the filter cartridge 7 from the hydromechanical effect of the stream. Getting on the blades 10, the solution receives a rotational-translational motion. The compact internal device of the filter provides a high speed of the swirling flow, which contributes to its effective cleaning. The centrifugal force created by the swirling flow discards the needle-like particles of undissolved impurities to the wall of the housing 1, along which they are deposited and accumulate in the pocket 16. Through slots 8, which are made at an angle and form a chevron optically dense structure without reducing the flow area, the solution is additionally filtered , enters the internal cavity of the filter cartridge 7 and further into the transport line.

The nitric acid solution circulating in pocket 16 dissolves the precipitated particles of undissolved impurities. Through the grooves 17, due to the ejector effect, the solution is sucked from the pocket 16, thereby enhancing the process of movement of the solution in the pocket 16 and the dissolution rate of the precipitated undissolved particles increases.

The vertical design of the slotted centrifugal filter during an emergency stop allows undissolved impurities to settle either in the annular pocket or along the inlet pipe into the solvent apparatus without clogging the filter cartridge.

The proposed device allows you to pre-clean the solution before it approaches the filter cartridge, thereby increasing the life of the device between successive washes of the filter cartridge.

The design of the annular pocket provides effective dissolution of sediment, preventing entrainment and loss of expensive substances.

Thus, the application of the proposed device allows to simplify the design to increase its throughput and increase the efficiency of cleaning from under-dissolved impurities of nitric acid solutions obtained in the process of dissolution of nuclear fuel.

Claims (2)

1. A centrifugal slit filter, comprising a housing with a nozzle for supplying a cleaned medium, a coaxially located filter cartridge with evenly distributed slots, a cowl, a flow swirl made of blades, and a receiving chamber, characterized in that the vertically located housing consists of an upper cylindrical part, the lower part in the form of an inverted truncated cone, upper cover and lower cover, to which a pipe is connected for supplying the medium to be cleaned, the blades of the flow swirl are stationary are mounted on the fairing and have end conical bevels, the filter further comprises a nozzle, the inlet of which is connected to the bottom cover of the casing and provided with grooves along the perimeter, and the outlet of the nozzle has an inclination angle equal to the angle of inclination of the conical bevels of the blades, while the nozzle and the conical wall form an annular pocket, which is the receiving chamber. 2. The filter according to claim 1, characterized in that the inlet nozzle of the nozzle is centered in an annular groove grooved in the lower housing cover.

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