GOST R 51568-99

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  ГОСТ Р 51568-99

GOST R 51568−99 (ISO 3310−1-90) laboratory Sieves of metal wire mesh. Specifications

GOST R 51568−99
(ISO 3310−1-90)

Group В76

STATE STANDARD OF THE RUSSIAN FEDERATION

LABORATORY SIEVES OF METAL WIRE MESH

Specifications

Test sieves of metal wire cloth.
Specifications

OKS 19.120
AXTU 1209

Date of introduction 2000−03−01

Preface

1 DEVELOPED by the State scientific institution «all-Russian scientific research Institute of grain and products of its processing» (GNU vniiz)

SUBMITTED by the Technical standardization committees TC 2 «Grain products and oilseeds» and TC 146 «Hardware"

2 ADOPTED AND put INTO EFFECT by the Resolution of Gosstandart of Russia from December 22, 1999 No. 567-St

3 this standard is the authentic text of ISO 3310−1-90 «SITA lab. Technical requirements and test methods. Part 1. Laboratory sieves of metal wire mesh», except sections 2, 9, 10

4 INTRODUCED FOR THE FIRST TIME

5 REISSUE

1 Scope

This standard establishes the technical requirements for laboratory sieves, made of metal wire mesh, and methods of their check (hereinafter — SITA).

The standard used for laboratory sieves with sizes from 125 mm down to 20 microns in accordance with ISO 565.

2 Normative references

The present standard features references to the following standards:

GOST 166−89 Calipers. Specifications

GOST 515−77 Paper, wrapping bituminosa and tarry. Specifications

GOST 1050−88 hire gauged bars with special surface finishing of carbon structural quality steel. General specifications

GOST 2991−85 wooden disposable Boxes for loads up to 500 kg. General specifications

GOST 8273−75 wrapping Paper. Specifications

GOST 8828−89 base Paper and paper double-layer waterproof packaging. Specifications

GOST 12301−81 Cartons, cardboard, paper and combined materials. General specifications

GOST 15846−79 Products that are sent to the far North and remote areas. Packing, marking, transportation and storage

ISO 565−90* laboratory metal Sieves made of wire mesh, perforated metal panels and sheets made by the method of elektroustanovok. Nominal hole sizes

ISO 2395−90* SITA lab. Test methods. Dictionary
________________
* The original standards are in the Federal Fund state statistics.

3 Definitions

Terms and definitions — ISO 2395.

4 General requirements

4.1 Sieves are manufactured with a nominal cell size of the metal grid in accordance with tables 1 and 2.

4.2 Nominal sizes from 1 mm and more is expressed in millimeters, nominal dimensions less than 1 mm in micrometers.

5 Requirements for the mesh made of metal wire

5.1 Permissible variation in cell size and wire diameter

Permissible variation in cell size and wire diameter shown in tables 1 and 2.


Table 1 — Permissible variation in cell size and wire diameter

In millimeters

Table 2 — Permissible deviation of the cell size and wire diameter

In micrometers

5.1.1 Allowable deviation of size of cells

5.1.1.1 Allowable deviation of the cell size , and given in tables 1 and 2, is used for cell size measured along the Central lines of the cell (figure 1) on a duck and basis.

Figure 1 — grid Cell

 — cell dimensions; the diameter of the wire

Figure 1 — grid Cell

5.1.1.2 cell Sizes should not exceed the nominal size , µm calculated according to the formula

. (1)

5.1.1.3 deviation of the mean cell size should not exceed the nominal size for size , µm calculated according to the formula

. (2)

5.1.1.4 In a range of sizes from «nominal » to «nominal » to be no more than 6% of the total number of cells. The magnitude , m, is calculated by the formula

. (3)

If a sieve has less than 50 cells, in the range from «nominal » to «nominal » to be no more than three cells.

5.1.2 the diameter of the wire

5.1.2.1 values of the diameters of the wire mesh of metal wire are shown in tables 1 and 2.

5.1.2.2 the diameter of the wire used in laboratory sieve, must be the same in the basis, and duck.

5.1.3 Wire manufactured according to the normative documentation (ND), use steel grades 08KP; 20; 45 GOST 1050.

Frame of sieves are made of steel grades 08KP; 20; 45 GOST 1050.

6 Methods of verification

6.1 Methods of testing sieves

Each cell in the metal wire mesh being checked for compliance with technical requirements 5.1.

In the sieve with number of cells less than 20 and (fact 1) to check all cells.

In the sieve with number of cells more than 20 (2−4 calibration) calibration is carried out in the following order: determine the General condition of the wire mesh, considering individual cells and then measure the cells to determine their compliance with tolerances.

Verification 1. Define the General condition of the wire mesh

When checking inspect the wire mesh for evenly lit background. If there are obvious deviations from uniformity of appearance, such as obvious defects, creases, wrinkles, foreign matter, mesh to use is not allowed.

Calibration 2. The maximum dimension of the cells

Carefully and consistently inspect all cells for the detection of cells with increased size for subsequent measurements.

If the size of a single cell exceeds the nominal by more than the maximum allowable deviation , the sieve is rejected.

In the calibration 2−4 in the measurement of the cell size use equipment with a measurement accuracy of at least 2.5 microns or 1/10 of the average deviation from the nominal cell size.

Verification 3. Counting the number of cells, the dimensions of which exceed the criterion of «nominal size «

Count the number of cells or determine the relative proportion of cells, the dimensions of which (on an estimated area of sieves) do not exceed the criteria of the «nominal size » and «nominal size » (5.1.1).

If the number or relative proportion of cells exceeds the restrictions set out in 5.1.1.4, SITA considered unusable.

Verification 4. Measurement of average cell size and mean diameter of the wire

After evaluation of sieves in compliance with the verifications 1−3 measure the average cell size and wire diameter to estimate the area of the sieve.

The average cell size on the canvas sieve is measured for at least 10 cells in each direction (weft and warp) and not less than two sections of the sieve.

If the average cell size and wire diameter do not match are shown in tables 1 and 2, the sieve deem unfit to use.

The diameters of the two mutually perpendicular directions, the lengths of the sides of the screens and the frame height measured by Vernier caliper according to GOST 166.

6.2 Calibration frame sieves (shell)

For wider application it is recommended that the frame (sides) round shape with a diameter of 200 mm, especially for sieves of metal wire with a nominal cell size of 1 mm. the Circular shell of smaller size is used for fine grids and sifting of small sample mass. For sieves with larger cells use 300-millimeter shell of round or rectangular shape, and to sieve with cell sizes of 25 mm or more is allowed to use a larger shell. The shape and size of shells for laboratory sieves did not have a big impact on the outcome of screening.

If necessary, the diameter laboratory sieves 300 mm can be increased by 15 mm, but the diameter or the surface area of the mesh in the sieve, to ensure the effectiveness of the screening must be within the limits specified in table 3 and figure 2.


Table 3 — Form and dimensions of the sieve

In millimeters

Figure 2 — Cross section of a sieve

1 — shell (frame); 2 — mesh metal wire

Figure 2 — Cross section of a sieve

7 Design of sit

Design of shells for the ITA should include the opportunity to disassemble and reassemble the set of sieves with other shells, lids and bottoms with the same nominal diameter.

Mount metal wire grid shell must be made so that it is easy to fill a portion for sifting.

8 Marking

On a metal tag permanently attached to the shell must be specified:

— nominal cell size;

— the designation of the standard;

— material metal wire mesh back and sides;

— the name of the manufacturer or supplier;

— the identification number of the manufacturer.

9 Packing

9.1 the Sieve should be Packed in cardboard boxes according to GOST 12301 another ND or wrapped in paper according to GOST 8273.

9.2 packaged products are placed in wooden boxes according to GOST 2991. The boxes inside must be lined with waterproof paper according to GOST 8828 or paper according to GOST 515.

By agreement with consumer it is permitted other packaging ensuring safety of products during transportation and storage.

Packing boxes of goods when transporting them to the far North and remote areas — according to GOST 15846.

9.3 the Weight of boxes (gross) must not exceed 20 kg.

10 Transportation and storage

10.1 Sieve are transported by any means of transport in accordance with cargo carriage regulations applicable to transport of this species. The sieves should not be exposed to atmospheric precipitation and mechanical damage.

10.2 the boxes with the sieves is stored in Packed form in ventilated rooms with relative humidity not more than 75% in the absence of vapors of acids and alkalis.

The text of the document is verified by:
the official publication of the
Mesh metal. Types.
Specifications: Sat. Standards. -
M.: IPK Publishing house of standards, 2003