CN112110106B

CN112110106B - Rotary screen for pneumatic garbage conveying system

Info

Publication number: CN112110106B
Application number: CN201910528990.9A
Authority: CN
Inventors: 刘明利
Original assignee: Jike Shenzhen Environmental Protection Technology Co ltd
Current assignee: Jike Shenzhen Environmental Protection Technology Co ltd
Priority date: 2019-06-19
Filing date: 2019-06-19
Publication date: 2023-10-13
Anticipated expiration: 2039-06-19
Also published as: CN112110106A

Abstract

The utility model relates to a rotary screen for a pneumatic garbage conveying system, which is characterized in that after garbage is separated from gas by gas-solid separation equipment in the pneumatic conveying system, the gas is discharged by the gas discharge system, in order to prevent light matters such as paper scraps and the like from being discharged along with airflow winding, a gas-solid separation filter is arranged in a separator, a small number of floating garbage is isolated to avoid the discharge system, a disc-shaped or umbrella-shaped barrier is adopted for the rotary screen in the prior art, the separation problem is well solved, but the separation purpose cannot be completely achieved due to the fact that the centrifugal force is smaller than the resistance to be overcome at the central part.

Description

Rotary screen for pneumatic garbage conveying system

Technical Field

The utility model relates to a filtering device of a pneumatic or pneumatic conveying system, in particular to a rotary screen for a pneumatic garbage conveying system.

Background

The pneumatic conveying system is one bulk material conveying system, and the system utilizes blower to produce airflow to form great wind force to suspend material and drift in the conveying pipeline to reach the conveying aim, and the material is discharged into the specified position via gas-solid separating equipment, with the gas being exhausted to the system after being separated, the separator also including gas-solid separating filter to separate small amount of floating material to avoid the material from being exhausted to the system. The utility model relates to a material which is garbage, various kinds of garbage are absorbed into a central garbage collection station by strong wind power generated by negative pressure, the garbage is separated from air flow through a separator, a filter used by the garbage separator is split into two parts according to the characteristics of the garbage, one part of the filter is still arranged in the separator and is mainly used for blocking light large objects (hereinafter called floaters) such as paper, plastic films and the like which can easily float in the air, the other part of the filter is arranged behind the separator and is used for dust and smell filtering equipment, and the more advanced filters which are currently arranged inside the separator are a rotary barrier and a rotary scraper barrier (see patent application Nos. 201010198169.4 and 201320008427.7 and 201610474086.0 and 2016062437. X). 201010198169.4 the air current flowing through the filter drum flows in the opposite direction to the centrifugal force generated by the rotation of the filter drum, when the floating paper is impacted to the surface of the filter drum by the air current winding belt and can not pass through the filter drum by the grid, wind pressure is formed on the paper due to the action of the air current, the paper is pressed on the outer peripheral surface of the filter drum, the rotating filter drum rotates the paper to obtain the centrifugal force, when the centrifugal force of the paper is larger than the acting force generated by the wind pressure, the paper is separated from the filter drum, and then the paper stall is pressed against the filter drum again by wind force, so that the paper is in a 'suspension' state, and in the suspension state, the wind direction determines the position of the paper, so the paper can not be thrown off at all, and the subsequent paper is accumulated continuously, the flow area of the filter drum is continuously reduced, the airflow velocity of the airflow passing through the filter drum is continuously increased, the air pressure in direct proportion to the square of the flow velocity is continuously increased in an index way until the centrifugal force is smaller than the pressure generated by the air pressure, the filter drum is blocked by paper and is forced to stop for cleaning, meanwhile, the air blowing groove forms airflow in a gap between the end face of the filter drum and the end face of the air outlet bin by utilizing negative pressure, the airflow is blown out of the inner barrel of the filter drum by the air blowing groove, when paper is attached to the filter drum, the pressure outside the filter drum is gradually increased until the airflow is larger than the pressure in the air blowing groove, the flow direction of the airflow is reversed, the blowing function is lost, and the paper enters the air outlet bin from the gap, so that the effect is lost; 201320008427.7 a filter cone for use in the front end of a centrifugal separator is proposed, the filter cone is fixed and not rotated, a rotary blade is provided outside the filter cone for scraping off the floating matters adsorbed on the filter cone, as in the filter cone, the scraped floating matters are not far away from the air outlet and still blown and sucked again onto the filter cone under the action of wind force, and the key is that the scraper is unable to act against the plastic film attached to the filter cone and the scraper is wound by the plastic film; 201610474086.0 and 2016062437. X propose a method capable of avoiding throwing and re-sucking, which is realized by adopting a disc-shaped grating, and meanwhile, the utility model and the utility model propose a disc-shaped grating, but specific characteristics of the disc-shaped grating are not described, and only disclosure is made from the aspect of rigidity.

Disclosure of Invention

In order to solve the problems, the utility model is further supplemented with the characteristics of the dish-shaped grating involved in 201610474086.0 and 20160643377. X, and is characterized in that a dish-shaped grating is arranged at the inlet end of an air outlet bin, the area of the dish-shaped grating close to a central shaft is not through-flowing, friction between a blocked object and the grating (no matter the outline of the grating is emphasized, the grating is abbreviated as grating below under the condition of de-emphasizing the outline of the grating), the critical radius of the area is in proportion to the sine value of the friction angle and is in inverse proportion to the square of the rotation angle speed of the grating, the male surface of the grating is a windward surface, and the complementary angle of the included angle between a bus of the male surface and the central shaft is a tangential angle, so that the tangential angle is smaller than 90 degrees; the shape of the grating is similar to that of a conical surface, tangential angles at any radius position are the same, or the grating is similar to a bowl shape, tangential angles at different radii from a central shaft on the generatrix are different, the smaller the radius is, the larger the tangential angle is, the larger the radius is, the largest tangential angle at the critical radius is a friction angle, the smallest tangential angle is 0 degree, or the larger the radius is, the smaller the tangential angle is in a region with larger radius, the similar to that of a straw hat; the inlet end of the air outlet bin is provided with a plurality of layers of barrier ribs which are coaxially arranged front and back and comprise a main barrier rib and a front barrier rib, wherein the front barrier rib faces the wind in front or one or more than one layer, the main barrier rib is arranged behind all the front barrier ribs, and the main barrier rib completely covers the inlet of the air outlet bin; the multiple layers of the barrier ribs either share one shaft to rotate at the same angular velocity, or are coaxial but not coaxial, rotate at different angular velocities, and the main barrier ribs either rotate or do not rotate; the front grating is only provided with radial grating bars, and a small number of circumferential grating bars are not arranged or are required to be arranged, and the circumferential grating bars are required to be arranged on the lee side of the radial grating bars if the circumferential grating bars are arranged; the flow is not conducted in a region range of the multi-layer barrier close to the central axis, and the critical radius of the region range is in direct proportion to the friction angle and in inverse proportion to the square of the rotation angular velocity of the barrier; the center of the windward side of the barrier or the multi-layer barrier is streamline like the center windward head of the propeller of the airplane. The surface of the grating at the same radius is wavy. The windward side of the grating is a radial grating, and the circumferential grating connected with the radial grating is on the leeward side.

The circular inlet end of the air outlet bin is provided with a grating, the outer diameter of the grating is larger than the caliber of the inlet end of the air outlet bin, the inlet of the air outlet bin is completely covered, the center of the grating is connected with a rotatable shaft, the rotatable shaft is coaxial with the geometric central axis of the grating, the rotatable shaft is a power shaft, the grating rotates along with the power shaft when the power shaft rotates under the driving, when paper floating in air flow is wound on the windward side of the grating by the air flow, the paper is blocked by the grating and is attached to the grating, the paper rotates along with the grating due to friction force after being attached to the grating, and under the condition that tangential angles at different radiuses of the surface of the grating meet a certain rule, the paper slides to the edge of the maximum outer diameter of the grating along the surface of the grating, and is thrown to a position with minimum ascending wind force or even descending wind force, so that the purpose of separating the floating objects is achieved. The tangential angle and friction angle relationship provided by the utility model can reduce the non-flow area under the condition of meeting the relationship, thereby increasing the flow area, reducing the pressure loss generated by the barrier and reducing the power consumption.

Drawings

FIG. 1 is a schematic view of a grating

FIG. 2 is a diagram of a force analysis of floats adsorbed on a grating

FIG. 3 is a schematic view of a non-through-flow region in the center of rotation of a barrier

FIG. 4 is a schematic illustration of a plastic film or paper attached to a circumferential grid under wind pressure

FIG. 5 is a schematic illustration of a plastic film or paper attached to radial grid bars under wind pressure

FIG. 6 is a schematic illustration of the attachment of a plastic film or paper to radial bars undulating in circumferential direction under wind pressure

The outline of the straw hat-shaped barrier shown in FIG. 7 is schematic

The reference numerals in the figures illustrate:

1. an air outlet bin; 2. a separation bin; 3. a drive shaft; 4. a barrier; 5. central no-flow area

Detailed description of the preferred embodiments

The technical scheme of the utility model is further described in detail below with reference to the accompanying drawings:

the grid (4) is arranged in the separator in the inlet of the air outlet bin (1) to intercept floating objects which still float along with the air and are discharged out of the bin after being failed to deposit by centrifugal separation, the dish-shaped flying saucer is of a conical, bowl-shaped and straw hat-shaped structure, the top of the dish-shaped flying saucer is directed to the separating bin (2) of the separator, the driving shaft (3) is actively rotated at the side of the air outlet bin, an undesignated straight arrow in the figure indicates the airflow direction, the shape refers to the shape of a main structure through which airflow passes, namely the shape except for a non-ventilation part, in the utility model, the cone is in a frustum shape, the bowl-shaped flying saucer refers to the shape of a bus bar which consists of straight lines and curves, the shape of a smaller height is like a bowl, the shape of a cup is higher flying saucer refers to the shape of a bowl or the cup shape, the tangential angle of the bus bar is gradually reduced like a hat in the process of being far away from the center, and the shape of a small hat is like a straw hat in the process of which the hat is bigger.

FIG. 2 is a diagram showing the force analysis of a floating object adsorbed on a barrier, the floating object being blocked by the wind-driven tape at a position spaced from the central axis r by the surface of the barrier, the force including the pressure F of the air flow on the blocked object _p Centrifugal force F generated by rotation of the grating _a The included angle alpha between the tangential direction of the grating generatrix and the central axis where the separated object is located can be called a half apex angle, the rest angle theta is called a tangential angle, the centrifugal force at different radial positions is different, the component force along the tangential direction and the normal direction under different tangential angles is also different, and the normal component force, namely the product of the centrifugal force and the angle sine value is larger than F _p The suspension phenomenon can not be realized, therefore, the relation between the tangential angle and the radius needs to be satisfiedNamely, the larger the radius is, the smaller the tangential angle is, so as to avoid the phenomenon of suspension and incapability of throwing off, under the condition that the centrifugal force is ensured not to lead the blocked object to be in a suspension state, the tangential component force needs to be larger than the friction force f so as to lead the blocked object to slide towards the edge of the barrier to truly break off the barrier to realize throwing off, and the tangential angle of the bus at different radiuses of the barrier is related to the friction angle and the radius and is reduced along with the increase of the friction angle and is increased along with the increase of the radius, and the function expression is that->I.e. dish-shaped motherThe maximum angle of the allowable tangential angle of the line at different radiuses is different (namely, the generatrix is a curve), the allowable tangential angle at the position with small radius is small, the allowable tangential angle at the position with large radius is large, the allowable shape boundary is similar to a bowl, the bowl bottom is flatter, and the bowl edge is steeper, so the utility model proposes that the shape of the barrier is similar to a bowl, the tangential angles at different radiuses are different, the tangential angle closer to the rotation center is smaller, and the tangential angle farther from the rotation center is larger. If the grating is made into a cone shape (namely, the generatrix is a straight line), as long as the critical radius of the grating meets the requirement, other radiuses can meet the requirement, the maximum tangential angle at the critical radius of the grating is a friction angle, and the minimum tangential angle is 0 degree no matter the grating is bowl-shaped or cone-shaped. The requirement that the maximum tangential angle becomes larger along with the increase of the radius usually occurs in a region with a relatively small radius, while the requirement that the maximum tangential angle becomes smaller along with the increase of the radius usually occurs in a region with a larger radius, and the shape formed under the boundary condition is similar to a straw hat, namely, a straw hat is buckled with a bowl on a cone shape or a disc shape, the boundary of the straw hat is a static balance boundary, namely, the boundary of static and sliding, the tangential angle is smaller than the boundary requirement, and the sliding capability is stronger, so that the cone shape or the disc shape with the tangential angle smaller than the friction angle is easier to throw off a blocked object than the straw hat, but the straw hat has the advantage of large flow area.

In the diagram of the central area of the barrier in fig. 3, r0 represents the radius of the minimum non-through-flow area, namely the critical radius, d0 represents the critical diameter of the whole non-through-flow area, the utility model proposes that the non-through-flow is not carried out in an area range d0 of the barrier, which is close to the central axis, and the critical radius of the area range is in direct proportion to the sine value of the friction angle and in inverse proportion to the square of the rotation angular velocity of the barrier.

Under a certain rotation speed, the blocked object in the central area cannot be thrown off due to the fact that the tangential component force of centrifugal force is smaller than the friction force generated by gas pressure, when the floating object is larger, the surface center of the floating object just falls at the center of the rotating shaft, or the floating object is not large, but is adsorbed in the area, the floating object cannot be thrown off, and in order to solve the problem, the utility model proposes that the blocking object is not through-flowing in an area where the blocking object is connected with the rotating shaft, and the surface of the windward surface of the blocking object is smooth, namely, the blocking object is not through in a certain radius range near the rotating center of the rotating blocking object at the connecting part of the blocking object and the rotating shaft. The maximum tangential angle at the critical radius is the friction angle, the minimum tangential angle is 0 degree, the critical radius is the critical radius which meets the relation, but when the sacrifice flow area adopts a larger no-flow area, namely the radius of the no-flow area is larger than the critical allowable value, the tangential angle at any radius of a generatrix of the no-flow area does not need to meet the friction angle requirement but is smaller than 90 degrees.

The higher the friction factor between the surface of the barrier and the blocked object, the higher the required rotating speed, and the function relation is expressed as

The friction angle is also a factor influencing the rotational speed, and reducing the friction coefficient can reduce the rotational speed requirement.

When the circumferential bars are on the windward side and the radial bars are on the leeward side, as shown in fig. 4, the plastic film or paper attached to the circumferential bars is sunk between the bars under the action of wind pressure, the movement of the paper is blocked by the bars as indicated by Fa in the figure, which is equivalent to increasing the friction coefficient, while if the radial bars are arranged in front of the circumferential bars, when the paper deformation does not touch the circumferential bars, as indicated by arrows in fig. 5, the direction of movement of the paper is tangential to the paper surface, the friction coefficient is the friction coefficient between two materials (except for other uncertain factors such as electrostatic adsorption) without being blocked by deformation, and the direction of the visible windward bars should be radial or quasi-radial. Therefore, the windward side of the grating is a radial grating, and the circumferential grating connected with the radial grating is on the leeward side.

Another benefit of the radial bars is that the wind vibration of the paper is easily generated by the wind speed of the curved surface shape of the paper relative to the cyclone wind under high-speed rotation of the bars, and the wind vibration is beneficial to reducing the friction coefficient. Of course, another assumption is also made that the barrier is made to be wavy in the circumferential direction as shown in fig. 6, as a result of which a lift force can be formed on the back wave surface, which is to be studied further.

The contour of the straw hat-shaped grating shown in fig. 7 shows that tangential angles at different radiuses are smaller than those of the critical straw hat shape, namely, the grating is formed by any shape between the critical straw hat and the disc shape, such as conical shapes with different cone angles, so long as the tangential angles are not negative values, the purpose of throwing off can be achieved, the disc shape is convenient to manufacture, the cone shape has rigidity, the flow area of the straw hat shape can be larger, and the wind resistance is smaller.

Claims

1. A rotary screen for pneumatic garbage conveying system features that a disk-shaped barrier is arranged at the inlet end of air outlet, the external diameter of said barrier is greater than the diameter of inlet end of air outlet, and the inlet of air outlet is fully covered.

2. A rotary screen for a pneumatic waste conveying system as claimed in claim 1 wherein the dish-like grating is shaped like a cone with the generatrix of its surface being straight and the tangential angle being the same at any radial position.

3. A rotary screen for a pneumatic waste conveying system as claimed in claim 1 wherein the dish-like grating is bowl-like in shape and the tangential angle at different radii from the central axis on the generatrix is different, the smaller the radius the smaller the tangential angle and the larger the radius the larger the tangential angle.

4. A rotary screen for a pneumatic waste conveying system as claimed in claim 1 wherein the dish-like grating is shaped like a straw hat and the tangential angles on the generatrix at different radii from the central axis are different.

5. A rotary screen for a pneumatic waste conveying system as claimed in claim 1 wherein the dish-like grating has any shape intermediate the critical straw hat and the dish-like shape.

6. A rotary screen for a pneumatic waste conveying system as claimed in claim 1 wherein the surface of the dish-like grating at the same radius is undulating.