SU1255172A1 - Air filter - Google Patents

Description

one

The invention relates to a locomotive building and is intended for air filtration systems, cooling electrical machines and diesel locomotive equipment, as well as for any electrical installations with forced air cooling.

The purpose of the invention is to increase the dust holding capacity and the service life of the filter, as well as reducing the cost of its maintenance.

FIG. 1 shows the air filter; FIG. 2 shows a variant of the air filter.

The air filter consists of the frame 1, the entrance louver 2, the outlet pipe 3 and the filter; its element 4, made in the form of a single layer oiled elastic. a porous material with a thickness of 14–15 times the average cell size has a specific aerodynamic resistance of (4–5) 10 1 / m, the opening of which is carried out by burning off the membranous partitions,

The device works as follows.

The air enters through the louver 2 of the frame 1, passes through the filter element 4 and the output

pipe to .3 k. fan (not shown) When air passes through the filter in the initial period of time, the main part of the delayed pypi is in the first layers of the material along the flow. Later, as the saturation intensifies, deeper layers enter a decrease in the active surface of the filter and a decrease in efficiency, and because of a decrease in the living cross section, an increase in aera.dynamic resistance is observed. The steepness of the decrease in efficiency and an increase in resistance depend on the thickness of the material and the cell size. The smaller and smaller the pores, the smaller the drop in efficiency and the greater the value of m, the steeper the increase in resistance and the smaller the value of ga, where nig is the dust capacity determined by the minimum allowable degree of dust collection efficiency; mn is the capacity weighted aerodynamic drag.

This dependence of the thickness of the filter element on the average cell size ensures

722

Equality w MQISC If the equality is not fulfilled, the capacity is determined by the minimum value of m "or T", i.e. filtering properties are reduced.

In addition, t and m are influenced by aerodynamic resistivity. This value is determined by

4H

Нц --3 U V

f

one

, -, which

M

characterizes the degree of pore opening, depends on their dimensions and technological parameters of the internal surface of the substance; where dN is the increment of resistance of the dust-free material, kgf / m (Pa); uV is the increment of the flow velocity through the filter, m / s, (U is the dynamic viscosity of air, kgf-s / (Pa, s).

Dp of the air filter, the optimal values of these parameters (resistivity, specific capacity, ratio of thick to the average cell size) are established.

Table 1 presents the test results of filter elements.

In tab. 2 shows the parameters of filter elements with a maximum specific capacity.

The service life of the filter elements depends on the pore opening method.

The physicomechanical parameters of the leached material due to the weakening of the structure and the effect of alkali residues and acids decrease 2-3 times faster, respectively. The same service life time of the targeted material is less, i.e. alkaline-free opening of the pores allows to increase the physical and mechanical properties and the service life of the materials.

The comparison was carried out according to the parameters: dp - tensile strength (breaking stress); p is the relative elongation at the time of rupture (characterizes the elasticity of the material); b — stress upon compression of material by 20% (a sharp increase in b j means that the material becomes brittle).

Getting open porous polyurethane foam, which is used as filters, takes place in two stages. The first is to produce polyurethane-based polyurethane foam by foaming. As a result, an elastic porous material is obtained.

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consisting of a rigid mesh frame and thin membranes stretched between the frame elements. These membranes greatly impede the passage of air - they must be removed. Membrane Removal - Second Process Stage

The opening of the pores of the proposed filter is carried out by the method of burning off partitions - membranes (method of controlled burning). In this method, only the membranes are melted (the process is very fast) without hauling the skeleton (the skeleton does not have time to warm up and melt). By this, the active filtering surface, (}) of the physical-mechanical properties, remains stable and aerodynamic drag is obtained. Due to the greater filtering surface

/ with a stable aerodynamic resistance and preserving the physicomechanical properties of the material treated by heat, has a high dust holding capacity and a service life compared with an alkali treated filter,

five

50

five

1724.

According to the data, it can be seen that the specified properties for leached material fall 2-3 times faster than the treated me (by cutting off partitions, therefore, the service life of the latter is also 2-3 times longer. And than longer life and material penetration the lower the cost of its maintenance and replacement.

It was established experimentally that if the parameters of the filtering material are outside the specified limits, then technical and economic indicators are worsened all over. That is, if the resistivity falls outside the limits of (4-5) 10 1 / m and the ratio of the thickness of the material to the cell size falls outside the limits 14-15, then the specific dust capacity does not reach the maximum. When reducing the maxi. The maximum dust capacity below 1600 g / m deteriorates the filter performance - its maintenance costs increase. With an increase in .. the maximum dust capacity in excess of 10,800 s / m, the dimensions of the filter dramatically increase, its labor intensity, power to drive the fan, fuel consumption of the engines,

Table 1

selected by the minimum value

nif, or fllh

Table 2

cpu2.2

Claims (1)

AIR FILTER, for example, for an air supply system for an electric locomotive equipment, comprising a frame with a filter fixed therein. filter element made of oiled elastic porous material, for example polyurethane foam, characterized in that, in order to increase the emptying capacity, the service life of the filter, as well as reduce the cost of its maintenance, the filter element is made 14-15 times thicker the average cell size, specific aerodynamic resistance (4-5) -10 1 / m, maximum specific dust capacity of 1600 10800 g / m ² . Φί / gf