RU1783381C - Method of determining filter pressure loss - Google Patents

Abstract

The invention relates to filtering a liquid. A sample of filter material is spilled, taking into account which the dependence of the pressure drop across the sample on the fluid velocity is determined. The filter housing is spilled, taking into account which the pressure difference across the housing is determined as a function of the fluid velocity. The filter resistance is determined using the obtained dependences of the pressure drop across the filter material and the filter housing on the fluid velocity. A silt.

Description

The invention relates to filtering liquids.

A known method for determining the hydraulic resistance of a filter is that the filter is installed in the pressure line of the pouring stand, liquid is passed through it and the dependence of the pressure loss - pressure drop across the filter on the fluid velocity - filtering rate is determined.

The disadvantages of the known method are: -low accuracy due to the fact that when filter spills on a pouring stand (especially a filter with a high degree of purification), it is possible to clog the cells of the filter material with impurity particles contained in the pouring liquid of the stand, which distorts the resistance characteristics; - significant costs for conducting filter spills, especially filters with high throughput; for example, to determine

The hydraulic resistance of the filters, in which the housings are the same, but the filter materials are different, in accordance with the described method, it is necessary to spill each filter, which leads to high costs.

Closest to the proposed method is a method for determining the hydraulic resistance of a filter, which consists in passing liquid through a filter material, a mesh, and determining the coefficient of resistance of the mesh, using which the hydraulic resistance, pressure loss on the filter, is determined.

The disadvantage of this method is the low accuracy of determining the hydraulic resistance of the filter, due to the fact that in accordance with the described method only the resistance of the filter material is taken into account, and the resistance of the filter housing is not taken into account

with

h

00

s co

pa, i.e. it is believed that the resistance of the filter is only due to the resistance of the filter material.

The aim of the invention is to increase the accuracy of determining the hydraulic resistance of the filter and reduce costs.

The goal is achieved in that the determination of the hydraulic resistance of the filter is carried out by pouring a sample of the filter material with which the filter is equipped. liquid and determining the dependence of the pressure drop across the sample on the speed of the liquid; spillages of the filter housing and determining the dependence of the pressure drop across the housing on the fluid velocity; using the obtained dependences, the hydraulic resistance of the filter is determined from the equation

ARF DRFM + DRK,

where D Rfm - hydraulic resistance of the filter material;

DRK - hydraulic resistance of the filter housing.

In this case, filter material spills are carried out in laboratory conditions by passing a liquid through a sample of filter material, determining the dependence of the pressure drop on the liquid velocity and determining the material characteristics, for example, viscosity coefficients a and inertial / resistance equations

- 2

+ 2,

where A is the coefficient of hydraulic resistance of the filter material:

 2-arfm.

Re-Reynolds number during fluid flow through filter material :.

Re- (f)

And RFM is the pressure drop during the flow of fluid through the filter material;

L / fm - filtration rate - fluid velocity through the filter material:

Shfm 6 / rrfm;

G is the fluid flow rate through the material;

Rfm - the area of the filter material;

h is the thickness of the filter material;

CE, ft - coefficients in viscosity and

 inertial filter resistances

material determined experimentally from the results of sample filtering spillages.

Spillages of the filter housing are carried out on pouring stands by passing liquid through the housing, determining the dependence of the pressure drop on the fluid flow (fluid flow rate) and determining the characteristics of the filter housing from the results of pouring, for example, the following equations:

Ј -

 and

+ b

(2)

where § is the coefficient of hydraulic resistance of the filter housing:

10 15 20

25 30

3540

.

"P

g

Ј

2-DRK

pw2

Re “is the Reynolds number:

Rek

D Pk is the pressure drop during fluid flow through the filter housing;

p is the density of the liquid;

fi is the viscosity of the liquid;

W is the fluid velocity calculated by the conditional filter diameter d;

a, b - constants determined by the results of spillages of the filter housing.

After that, using the characteristics of the filter material (equation describing the hydraulic resistance of the filter material, including the coefficients ct, j8,} and the characteristics of the filter housing (equation describing the hydraulic resistance of the filter case, including the constant a. b), determine the hydraulic resistance of the filter at a given flow rate through the filter

 + ARC (3)

where A Rf is the pressure drop across the filter, and the resistance of the filter material is the pressure drop across the filter material A Rfm is determined from equation (1) after substituting the values included in it:

A RFM - ЩЛ НУУфм + ft hp 1Л / 2фм (4)

its resistance of the filter housing is determined from equation (2) after substituting the values included in it:

.W + .W2

(5)

Fig. 1 shows a device for pouring a sample of filter material: Fig. 2 shows the pressure drop across a sample of filter material as a function of fluid velocity; Fig. 3 is a pouring stand for pouring a filter housing; Fig. 4 shows the pressure drop across the filter housing versus the fluid velocity.

The method is carried out as follows.

Under laboratory conditions (Fig. 1), a sample of filter material 1, which the filter is equipped with, is installed in the housing of the device 2, and liquid is passed through it at various costs. In this case, the pressure drop across the filter material is measured by the sensor 4, the liquid flow rate by the sensor 3, the temperature by the sensor 5. The dependence (Fig. 2) of the pressure drop across the filter material A Rfm on the fluid velocity through the material L / fM is determined and then the values of the coefficients in the viscosity inertial / 9 resistance of equation (1), i.e. get the equation describing the hydraulic resistance of the filter material, which includes the coefficients in the akostnrgo and inertial / resistance.

Then, in the line of the pouring stand (FIG. 3), including the tank with liquid 1, pump 2, shut-off and control elements, the filter housing 3 is installed and liquid is passed through it, while the flow rate is measured by the sensor 4, and the pressure drop by the sensor 5, the temperature of the liquid - sensor 6.

According to the results of the spillings, the dependence (Fig. 4) of the pressure drop across the filter housing A Pk on the fluid velocity w calculated according to the conditional diameter d of the filter and then the values of the coefficients a and b of equation (2), i.e. get the equation describing the hydraulic resistance of the filter housing.

After that, using the equation f 1) - (2), determine the hydraulic resistance of the filter at a given flow rate

DRF DRfm + DRk,

where A rfm is determined from the equation (.transformed to (4);

And Pk is determined from equation (2) converted to the form (5).

Using the proposed method for determining the hydraulic resistance of a filter provides an increase in the accuracy of determination, since the method takes into account the contribution of each component - the filter housing and filter material. In addition, they reduce costs due to the fact that when using a series of filters having the same housings but equipped with different filter materials, the resistance of the filter materials is determined in laboratory conditions, and the hydraulic resistance of only one filter housing is determined on the pouring stand and exclude spills of other filter housings.

Claims (1)

The claims A method for determining the hydraulic resistance of a filter, including siphoning the filter material with which the filter is equipped, and determining, taking into account its dependence of the pressure drop across the filter material on the fluid velocity, characterized in that, in order to increase the accuracy of determination and reduce costs, production pouring the filter housing, taking into account which the dependence of the differential pressure on the fluid velocity is determined, and the hydraulic resistance of the filter is determined using the obtained dependences of the differential pressure on filter material and filter housing versus fluid velocity, from the equation ARF DRFM + DRK where A Rfm - hydraulic resistance of the filter material; DRC - hydraulic filter housing. f (/ g.Z DR ff & pfi. Editor T. Velska Compiled by V. Ishchenko Tehred M. Morgenthal, fig a Proofreader N. Buchok