RU72949U1 - EJECTOR - Google Patents

Abstract

The utility model relates to equipment for pneumatic transportation of various bulk materials and may find application in the pulp and paper industry.

The utility model allows to obtain a technical result, which consists in increasing the productivity of the pneumatic transportation process.

An ejector comprising a horizontal mixing nozzle connected at one end to a source of compressed gas and the other to the initial portion of the transport pipeline, a loading nozzle located above the mixing nozzle and communicated with the upper part of the latter, and placed in the mixing nozzle in the area of its communication with the loading nozzle a plate cantileverly fixed with its upper end on the upper wall of the mixing nozzle inclined to the lower wall of the latter towards the initial section of the transport pipe rovoda able to change its angle of inclination adapted to orifices arranged in horizontal rows equally spaced along its length at an angle to its plane. The plate is made with equally increasing from its upper part to the lower angle of inclination of the axes of the holes of each row to the plane of the plate from the angle of inclination of the plate to an angle of 90 °, while the angle of inclination of the axes of the holes of each row to the plane of the plate is equal to:

Where:

γ _n is the angle of inclination of the axes of the holes of the n-row; hail;

- the angle of inclination of the plate to the axis of the mixing pipe, deg;

t is the step between the rows of holes in the plates, mm;

n is the serial number of the row of holes along the length of the plate from its upper to lower

l is the length of the plate between the first and last rows of its holes, mm

1 s.p. F-ly, 2 ill.

Description

The ejector relates to the field of pneumatic transport, in particular, to devices for introducing bulk materials into the pneumatic pipeline, and can be used in various industries, for example, in pulp and paper for unloading tanks and wagons with soda ash.

Known ejector feeder (application No. 57-41412, IPC B65G 53/40, 1974, Japan), consisting of air and loading nozzles and an element that provides a vacuum in the zone of flow of bulk material into the transport pipeline. Such elements are most often an inclined plate, which forms a narrowing channel-nozzle with the walls of the air pipe. The disadvantage of this device is the possibility of blocking the pipeline with bulk material due to the fact that the latter enters the pipeline in a continuous stream from the loading pipe. As is known, to ensure the reliability of pneumatic distribution, bulk material after entering the pipeline must undergo two operations: separation of the material particles from each other (fluidization) and acceleration of the particles to the speed of the conveying stream. Due to the high energy intensity of these operations, it is not always possible to carry out them simultaneously at the same time due to the limited power availability of the flow, as a result of which material that has not had time to accelerate accumulates under the loading nozzle, clogging the pipeline.

Known ejector feeder as.with. 1024400, IPC In G53 / 28, 1985, in which, with the aim of increasing the reliability of the feeder, an attempt was made to sequentially carry out operations of aeration of particles and their dispersal, and thus to avoid blockages. It consists of an air nozzle, a loading nozzle mounted in it, an inclined plate,

located in the air pipe under the boot pipe, and a louvre grille located under the inclined plate. The feeder operates as follows. When supplying transporting air to the air pipe, the air passing under the inclined plate increases its speed when the flow cross section is narrowed, as a result of which the speed reaches its maximum value in the narrowest place (under the lower edge of the inclined plate), the pressure in the flow and in the space under the inclined the plate falls and air suction from the atmosphere begins along the channel between the inclined plate and the louvre grille. Atmospheric air passing through the slots of the louvre grille aerates the bulk material, thereby facilitating the following operation - its acceleration by the flow of conveying air when leaving the louvre grille. A significant drawback of the feeder is the use of atmospheric air for material aeration, which is almost always moist. This is unacceptable in pneumatic transport, especially when working with hygroscopic powdery materials, which, for example, include soda ash. Moisture in the air helps moisturize the material, deposit it on the walls of the pipeline, clog it and the aspiration system (usually fabric filters) to separate dust from the transporting air. In addition, the presence of a louvre grille complicates the design of the feeder. The presence of a continuous inclined plate causes a significant increase in aerodynamic drag and a decrease in the efficiency of the air flow.

As a prototype, a device was selected for introducing bulk materials into a horizontal pneumatic conveying pipeline along a.s. 592687, IPC B65G 53/40, 1973. The device includes an air pipe and a loading pipe mounted therein, an inclined perforated plate located under the outlet of the loading pipe. One end of the inclined plate is pivotally fixed in the pipeline, and the other is connected to the drive to change the angle

her tilt. The device operates as follows: compressed air, passing through the perforation, aerates the material located on the inclined plate, and then pneumatically conveys the material through the pipeline. The disadvantage of the prototype is that the holes in the inclined plate are made perpendicular to the latter. Compressed air passing through such openings lifts the material, pressing it to the loading nozzle and increasing the pressure under the plate. As a result, more material back-up is required to ensure normal flow.

The purpose of the proposed utility model is to eliminate the indicated drawback, i.e. improving the flow of material from the loading nozzle of the ejector and reducing the energy consumption of pneumatic transportation.

This goal is achieved in that the plate is made with equal to increasing from its upper part to the lower angle of inclination of the axes of the holes of each row to the plane of the plate from the angle of inclination of the plate to an angle of 90 °, while the angle of inclination of the axes of the holes of each row to the plane of the plate is:

where γ _n is the angle of inclination of the axes of the holes of the n-row, deg;

α is the angle of inclination of the plate to the axis of the mixing pipe, deg;

t is the step between the rows of holes in the plate, mm;

n is the serial number of the row of holes along the length of the plate from its upper part to the lower;

l is the length of the plate between the first and last rows of its holes, mm

The essence of the utility model is illustrated in the drawing. Figure 1 shows a General view of the ejector, figure 2 shows a view along arrow A.

The ejector feeder consists of an air pipe 1, for example, of rectangular cross-section, a perforated inclined plate 2, pivotally mounted on the axis 3 and located under the loading hole, the loading pipe 4, mounted in the air pipe. The perforation step t of the plate is selected as follows:

t≥d _holes / sinα

where: d _{of holes} - hole diameter perforations;

α is the angle of inclination of the plate 2.

The position and dimensions of the oblique are completely determined by the angle of its inclination and the cross-sectional area of the pipe under its lower edge. The perforation of the inclined plate is made with equal to increasing from its upper part to the lower angle of inclination of the axes of the holes of each row to the plane of the plate from the angle of inclination of the plate to an angle of 90, while the angle of inclination of the axes of the holes of each row to the plane of the plate is equal to:

For the 1st row of holes, i.e. for n = 1, γ _n = α; for the last row of holes, where t (n-1) = 1, γ _n = 90 °.

The ejector feeder operates as follows. Transporting air enters the air pipe 1 and meets the inclined plate 2. At the same time, bulk material or its air mixture enters the loading pipe 4. Usually with pneumatic conveying P ₁ > P ₂ . The bulk of the transporting air, moving along the tapering channel formed by the plate 2 and the walls of the air pipe 1, picks up speed and has a maximum speed V ₃ in the section under the lower edge of the plate 2, due to which the pressure of the transporting air decreases, thereby decreasing. pressure under

plate P ₃ , which is compared or becomes less than P ₂ . Due to this, the effect of suction (ejection) of bulk material into the air pipe is ensured. A small part of the air enters through the perforation of the inclined plate and reduces the friction of the bulk material, which, on the one hand, ensures its uniformity in mixing with air and high quality mixing, eliminates the occurrence of blockages of material in the feeder, and on the other hand, reduces the aerodynamic drag of the inclined plate . The feeder completely eliminates the use of atmospheric air for aeration of bulk material. The angle of inclination of the plate a is chosen equal to the angle of repose of the bulk material, which, in the presence of perforation of the inclined plate, eliminates the phenomenon of freezing of the material on the working surfaces of the feeder. Performing perforation with an angle γ _{n of} variable perforation holes along the length of the inclined plate, varying from the slope of the inclined plate together to the angle of 90 ° at its lower edge, improves the flow of bulk material from the loading nozzle into the pneumatic conveying pipeline. The perforation holes in the place of attachment of the plate are located almost parallel to the direction of movement of the compressed air (or the axis of the pipeline). At this point, the bulk material is aerated in the direction of movement of compressed air, in contrast to the prototype, where aeration at the same place on the plate occurs perpendicular to the latter. Thus, in the ejector there is no “preloaded” bulk material when it leaves the loading nozzle and as a result, normal outflow of material into the pneumatic conveying pipe is carried out, and additional material back-up is not required to overcome the “preloaded” one. Calculations showed that, compared with the known device, the amount of back-up material in the loading pipe of the proposed device can be reduced by 20% compared to the prototype.

Thus, the proposed ejector provides better flow of bulk material from the loading pipe, and, as a result of this, by increasing the efficiency of the ejector feeder by about 10%, energy savings are achieved during the prime transportation of bulk material.

The proposed ejector for pneumatic transport of bulk materials is manufactured at the University of Plant Polymers for use in one of the pulp and paper industry.

Claims (1)

An ejector for pneumatic transportation of bulk material, containing a horizontal mixing nozzle communicated at one end with a source of compressed gas, and the other with the initial section of the transport pipeline, a loading nozzle located above the mixing nozzle and communicated with the upper part of the latter, and placed in the mixing nozzle in the zone its communication with the loading nozzle plate, cantilever mounted with its upper end on the upper wall of the mixing nozzle inclined to the lower wall along the latter towards the initial section of the transport pipeline with the possibility of changing the angle of its inclination made with holes arranged in horizontal rows with equal steps along its length, at an angle to its plane, characterized in that the plate is made with equally increasing from its upper part to the lower angle of inclination the axes of the holes of each row to the plane of the plate from the angle of inclination of the plate to an angle of 90 °, while the angle of inclination of the axes of the holes of each row to the plane of the plate is:

where γ _n is the angle of inclination of the axes of the holes of the n-row, deg; α is the angle of inclination of the plate to the axis of the mixing pipe, deg; t is the step between the rows of holes in the plates, mm; n is the serial number of the row of holes along the length of the plate from its upper to lower l is the length of the plate between the first and last rows of its holes, mm