RU2534090C1 - Centrifugal gas cleaner of dust and fluid drops - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: device comprises gas blower and flange separating fouled and clean gases. Said flange has gas passage bore for hollow rotor to be fitted therein and to be sealed in said flange. Rotor end and walls in clean gas area have one or more gas passage bores. Rotor opposite end in fouled gas area has bottom to inhibit gas passage. Rotor walls have long slots of holes arranged radially to rotor axis that featured curvilinear or zigzag-like shape in radial direction. Rotor runs in the flange gas bearing that doubles as a seal between said fouled and clean gas areas. Said seal is produced by overpressure in said bearing.

EFFECT: power savings, higher efficiency of dust separation, simplified design.

5 cl, 4 dwg

Description

The invention relates to the field of mechanical engineering, in particular to devices for cleaning air and gases from dust particles and liquid drops, and in particular to rotary devices for cleaning air and gases from dust particles and liquid drops.

The known design of the dust collector (patent RU 2122462 "Cross-flow rotary dust collector", IPC B01D 45/14, publ. 11/27/1998) containing a rotating rotor made in the form of an impeller of a cross-flow fan, housing, inlet and outlet nozzles, dust collector .

The disadvantage of this design is the low degree of gas purification. The dust collector cavities for the dust removed from the gas communicate with the purified gas line, and volatile dust fractions enter the purified gas.

Also known is the design of the dust collector (patent US 1420665 "Centrifugal separator", IPC A47L 5/24; A47L 9/16, publ. 06/27/1922), selected as a prototype and containing a centrifugal separator having common features with the claimed design, namely separation an element with openings for passage through them of a purified medium (gas or liquid).

This design has a drawback: in order to ensure the necessary degree of separation of gas and dust, the separator must rotate at a high angular speed (more than 10,000 rpm), which requires improved quality of materials used in the design, manufacturing techniques and increased specific energy consumption for cleaning the medium .

The technical task of the proposed technical solution is to reduce the specific energy consumption for air purification and increase the efficiency of dust collection, simplifying the design.

The problem is solved using the proposed centrifugal device for cleaning gases from dust and droplets of liquids, containing a fan or other mechanism that generates a gas stream, a flange that separates the dirty and purified gas regions, in which a hole for gas passage is made. A hollow rotor with a seal and with the possibility of free rotation is installed in the hole. The end face and the walls of the rotor installed in the region of the purified gas have one or more openings for the passage of gas, and the other end thereof in the region of dirty gas has a bottom that prevents the passage of gas.

According to the invention, extended slots or holes are made in the walls of the rotor located radially to the axis of rotation of the rotor.

The task is also achieved by the fact that the slots or holes have a curved or zigzag shape in the radial direction.

The task is also achieved by the fact that the rotor can be mounted in a flange in a gas bearing, which simultaneously performs the sealing function between the areas of dirty and purified gas.

The presence of a fan in the device allows the gas to move from the dirty gas region to the purified gas region.

The invention is illustrated as follows. In the region of dirty gas A, an excess pressure is created relative to the region of purified gas B. Dirty gas moves under the influence of a differential pressure into the rotor through slots made in the walls of the rotor. The movement of gas creates a high-pressure head acting on dust particles and liquid droplets. Under the influence of the gas pressure head, the force acts on the dust particles:

$$\text{Ra}=\text{CRa}\cdot \rho \text{V2 / 2}\cdot \text{S}\text{,}\text{(one)}$$

where Ra is the total aerodynamic force, N;

CRa is the dimensionless coefficient of total aerodynamic force;

ρV ^2/2 - velocity head, Pa;

S is the characteristic area of the streamlined body, m ² ;

ρ is the density of air, kg / m ³ ;

V is the flow velocity, m / s.

The total aerodynamic force is directly proportional to the kinetic energy of the flow, which, when flowing around the body, is transformed into friction energy in the boundary layer and into potential pressure energy. This factor is taken into account in formula magnitude ρV ^2/2. The influence of the dimensions of the streamlined body is taken into account by the characteristic area S, and the largest sectional area of dust particles was taken as the characteristic area. The dimensionless coefficient of total aerodynamic force CRa is determined empirically in the process of aerodynamic experiments or theoretical calculations.

At the same time, dust and liquid droplets falling into the slot unwind together with the rotor. Centrifugal force acts on particles of dust and droplets of liquid moving in a circle in a gap. The parameters and location of the slots (length, width, height, channel shape) are chosen so that at a certain distance from the entrance to the slot, the centrifugal force acting on the contaminants becomes greater than the force from the gas pressure head.

For a material point, centrifugal force is expressed by the formula:

$$\text{F}=\text{m r}{\omega }^{\text{2}}\text{(2)}$$

Where:

F is the centrifugal force applied to the body,

m is the body weight

ω is the angular velocity of rotation,

r is the radius.

The centrifugal force acting on dust particles in the rotor slit at a speed of 3000 rpm and a diameter of 300 mm is three orders of magnitude (a thousand times) greater than the force arising from the pressure head, calculated for the average values of the speeds of the gas being cleaned.

In this case, the centrifugal force acting on gas molecules is tens or hundreds of times less than the force acting on dust particles and liquid droplets, due to their different densities. Therefore, particles with a higher density overcome the gas pressure head, fly out of the rotor and fall down. And the cleaned medium, moved by the fan, passes through the inner cavity of the rotor and exits through the open end of the rotor into the region of the cleaned gas (upward in Fig. 1).

There is a wide range: pressure drops between the outer and inner parts of the rotor, the geometric dimensions of the holes in the walls of the rotor, such that the gas will go inside the rotor due to its lower density and then through the open end of the rotor to the region of purified gas B, and dust and liquid drops under the action of centrifugal force will be thrown out of the hole (gap) out into area A. For example: the density of air is 1.29 kg / cubic meter, and the bulk density of light graphite dust is 80 kg / cubic meter. 80 / 1.29 = 62 times. The density of water is 1000 kg / cubic meter, which is 775 times higher than the density of air. The same amount of centrifugal force acting on dust and water drops will be greater than acting on air.

The main advantage of the proposed design is that even with relatively low rotor speeds (3000 rpm) and pressure drops actually created by existing industrial fans, you can select the geometric parameters of the slots that allow only purified gas or gas containing dust of a certain disperse composition and density.

The essence of the proposed technical solution is illustrated by the drawing, where Fig.1, 2, 3, 4 presents a diagram of the device.

The centrifugal filter consists of: fan 3 or another mechanism that creates a gas flow from volume A to volume B, flange 2, which separates the dirty and purified gas regions. A rotor 1 is installed in the flange 2 (for example, with a bearing 4 or with a gas bearing 5) with the possibility of rotation relative to the flange 2. A seal 6 is made between the rotor 1 and the flange 2, which prevents the passage of gas. The hollow rotor 1 has the shape of a body of revolution. One of the ends of the rotor has a bottom 7, which prevents the entry and exit of gas. The second end 8 of the rotor 1 has openings (hole 9) for the exit of gas. In the walls 10 of the rotor 1 there are holes 11 (slit-like, round or other shape) for gas to enter the inner cavity of the rotor 1, the walls of which are located approximately radially to the axis of rotation of the rotor.

Claims (5)

1. A centrifugal device for cleaning gases from dust and droplets of liquids, containing a gas-generating fan, a flange that separates the dirty and purified gas regions, in which a gas passage is made, into which a hollow rotor is installed with the possibility of free rotation and with sealing in the flange, the end face and the walls of the rotor installed in the region of the cleaned gas have one or more openings for the passage of gas, the other end face of the rotor in the area of the dirty gas has a bottom that prevents the passage of gas, different I mean that in the walls of the rotor are made extended slots or holes located radially to the axis of rotation of the rotor. 2. The device according to claim 1, characterized in that the slots or holes have a curved or zigzag shape in the radial direction. 3. The device according to claim 1, characterized in that the rotor is mounted in a flange in the bearing. 4. The device according to claim 1, characterized in that as the seal is used to create increased pressure in the bearing. 5. The device according to claim 1, characterized in that the rotor is mounted in a flange in a gas bearing, which simultaneously performs the sealing function between the areas of dirty and purified gas.

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