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QC/T 794-2020 (QC/T794-2020)

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QC/T 794-2020: PDF in English (QCT 794-2020)

QC/T 794-2020
QC
AUTOMOBILE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.060
T 05
Replacing QC/T 794-2007
Internal-combustion engine industry filter paper
ISSUED ON: AUGUST 31, 2020
IMPLEMENTED ON: JANUARY 01, 2021
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 5
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 Categories ... 9
5 Requirements ... 9
6 Test method ... 12
7 Inspection rules ... 14
8 Marking, packaging, transportation and storage ... 16
Appendix A (Normative) Test method for corrugated paper thickness and corrugation
depth ... 18
Appendix B (Normative) Stiffness test method ... 21
Appendix C (Normative) Resin content test method ... 23
Internal-combustion engine industry filter paper
1 Scope
This document specifies the terms and definitions, classification, requirements, test
methods, inspection rules and marking, packaging, transportation, storage of internal-
combustion engine industry filter paper (hereinafter referred to as filter paper).
This document applies to filter paper for internal combustion engine filters.
2 Normative references
The contents of the following documents constitute the essential provisions of this
document through normative references in the text. Among them, for dated references,
only the version corresponding to the date applies to this document; for undated
references, the latest version (including all amendments) applies to this document.
GB/T 450 Paper and board - Sampling for testing and identification of machine and
cross direction wire side and felt side
GB/T 451.1 Paper and board - Determination of size and deviation
GB/T 451.2 Paper and board - Determination of grammage
GB/T 451.3 Paper and board - Determination of thickness
GB/T 454 Paper - Determination of bursting strength
GB/T 462 Paper, board and pulp - Determination of moisture content of analytical
sample
GB/T 742 Fibrous raw material, pulp, paper and board - Determination of ash
(575 °C and 900 °C)
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling
schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 30512 Requirements for prohibited substances on automobiles
GB/T 4687 Paper board pulps and related terms - Vocabulary
GB/T 5249 Permeable sintered metal materials - Determination of bubble test pore
size
GB/T 5453 Textiles - Determination of the permeability of fabrics to air
GB/T 10342 Paper - Package and mark
GB/T 10739 Paper, board and pulps - Standard atmosphere for conditioning and
testing
GB/T 14041.2 Hydraulic fluid power - Filter elements - Part 2: Verification of
material compatibility with fluids
GB/T 14656 Test method for burning behavior of flame-retardant paper and board
GB/T 28950.2 Road vehicles and internal combustion engines - Filter vocabulary -
Part 2: Definitions of characteristics of filters and their components
GB/T 35348 Diesel engines - Fuel filters - Method for evaluating fuel/water
separation efficiency
JB/T 12651.2-2016 Internal combustion engine - Filter paper for filters - Part 2:
Testing method
3 Terms and definitions
The terms and definitions, as defined in GB/T 4687 and GB/T 28950.2, as well as the
following terms and definitions, apply to this document.
3.1
Filter paper
Paper, which is made of natural or synthetic fibers or their mixtures with additives
and binders capable of separating solid particles or other substances from the fluids
(air, lubricating oil, fuel, other fluids), in which they are suspended.
3.2
Cured filter paper
Filter paper, which is impregnated with thermosetting resin.
3.3
Non-cured filter paper
Filter paper, which is impregnated with thermoplastic resin.
3.4
Mean pore size
Using the bubble test, the capillary's equivalent pore diameter, which is
corresponding to the group bubble point pressure, when the group bubbles
continuously and stably emerge from the surface of the filter paper, expressed in μm.
The amount of group bubbles is adjusted according to the corresponding instrument.
3.12
Resistance to humidity
The ability of air filter paper to retain its original performance, after being treated in
a high-humidity environment for a specified period of time, which is expressed by
the stiffness retention rate of the treated sample.
3.13
Resistance to liquid medium
The ability of engine oil and fuel filter paper to retain its original performance, after
soaking in a specified medium for a certain period of time, expressed by the burst
strength value after sample treatment, in the unit of kPa.
4 Categories
4.1 According to the resin treatment method, it is divided into cured filter paper and
non-cured filter paper.
4.2 According to the filter medium, it is divided into air filter paper, engine oil filter
paper, fuel filter paper (diesel filter paper, gasoline filter paper).
4.3 According to whether it is flame retardant, air filter paper is divided into flame
retardant air filter paper and non-flame retardant air filter paper.
4.4 According to the shape, it is divided into corrugated filter paper and flat filter paper.
4.5 According to the composition of the functional layer, it can be divided into single-
layer and multi-layer composite filter paper.
5 Requirements
5.1 Quantification
The quantitative nominal value of the filter paper is specified by the manufacturer,
expressed in g/m2. The quantitative limit deviation is ±5% of the quantitative nominal
value.
The resin content of the filter paper shall not be less than 18%. For special customized
filter paper, the resin content is determined through negotiation between the supplier
and the buyer.
5.11 Ash content
The ash content of the filter paper shall not exceed 5%. For special customized filter
paper, the ash content shall be determined, through negotiation between the supplier
and the buyer.
5.12 Humidity resistance
5.12.1 The stiffness retention rate of non-cured air filter paper shall not be less than
30%.
5.12.2 The stiffness retention rate of cured air filter paper shall not be less than 70%.
5.13 Flame retardancy
The combustion performance results of flame-retardant air filter paper shall meet the
following requirements:
a) The average after-flame time is not greater than 5 s;
b) The average carbonization length is not greater than 115 mm.
5.14 Resistance to liquid medium
After the lubricating oil filter paper and fuel oil filter paper are immersed in the
specified engine working medium, under high temperature or low temperature
conditions, the residual burst strength shall not be less than 50% of the nominal value
of burst strength.
5.15 Filtration efficiency and dust holding capacity
The original graded filtration efficiency, dust holding capacity, test method of the filter
paper are determined, through negotiation between the supplier and the user.
5.16 Water separation efficiency
The water separation efficiency and test method of fuel filter paper shall be determined,
through negotiation between the supplier and the user.
5.17 Prohibited substances
It shall comply with the provisions of GB/T 30512.
5.18 Dimension tolerance
The tolerance of filter paper roll's width shall not be greater than 5‰ of the specified
size. The paper roll adopts a standard core, which has an inner diameter of Φ76 mm.
Note: The size (tolerance) and core diameter of the filter paper roll can also be implemented,
according to the order contract.
5.19 Appearance
5.19.1 The number of joints for each roll of paper shall not exceed 2. Marks shall be
made on the end of the paper roll. The joints shall be firm.
5.19.2 The cut edge of the paper shall be neat. The end face of the paper roll shall be
smooth and clean. The roll shall be tight. The core shall not be loose.
5.19.3 The paper surface shall be clean. There shall be no appearance defects, such as
holes, wrinkles, cracks, stains, color spots, pulp blocks, etc. that affect the use.
5.19.4 The corrugation of corrugated paper shall be complete. The corrugations shall
be evenly arranged. The corrugated surface shall not be cracked.
5.19.5 The impregnation is uniform. There shall be no defects, such as delamination or
breakage when folding.
5.19.6 The marking lines on the wire side are continuous and evenly spaced. The wire
marks cannot penetrate to the other side of the filter paper. The marking spacing is 30
mm, 40 mm, 50 mm, 100 mm. It can also be implemented according to the provisions
of the order contract.
6 Test method
6.1 Collection and treatment of specimen
Specimens are collected according to the provisions of GB/T 450. The standard
atmospheric conditions for specimen processing and testing shall comply with the
provisions of GB/T 10739. If it is a filter paper treated with a thermosetting resin, it
shall be cured before the test. The curing temperature is 160 °C ± 10 °C; the curing time
is 15 min ± 2 min. The cured filter paper shall be placed at a relative humidity of (50 ±
2) % and a temperature of 23 °C ± 1 °C under standard atmospheric conditions for 4
hours, before testing.
6.2 Quantification
It shall comply with the provisions of GB/T 451.2.
6.3 Thickness
6.3.1 The thickness of flat paper shall comply with the provisions of GB/T 451.3.
6.15 Resistance to liquid medium
It shall comply with the provisions of GB/T 14041.2 and GB/T 454.
6.16 Filtration efficiency and dust holding capacity
6.16.1 The air filter paper shall comply with the provisions in 6.13.2 of JB/T 12651.2-
2016.
6.16.2 The oil filter paper shall comply with the provisions in 6.13.3 of JB/T 12651.2-
2016.
6.16.3 The fuel filter paper shall comply with the provisions in 6.13.4 of JB/T 12651.2-
2016.
6.17 Water separation efficiency
The water separation efficiency of fuel filter paper shall comply with the provisions of
GB/T 35348.
6.18 Prohibited substances
It shall comply with the provisions of GB/T 30512.
6.19 Determination of size deviation
It shall comply with the provisions of GB/T 451.1.
6.20 Visual inspection
The visual inspection shall be carried out, at a uniform illumination of about 300 lx
AND an eye distance of 500 mm.
7 Inspection rules
7.1 General
Each roll of filter paper shall pass the inspection of the inspection department of the
manufacturer; it can only leave the factory, after the inspection report and certificate of
conformity are attached.
7.2 Inspection classification
Inspections are divided into exit-factory inspection and type inspection.
7.3 Exit-factory inspection
The exit-factory inspection items shall be carried out according to the provisions in
Appendix A
(Normative)
Test method for corrugated paper thickness and corrugation depth
A.1 Measuring instruments
A.1.1 Measuring instruments include three parts: dial indicator, detection head,
measuring table.
A.1.2 The detection head is linear (see Figure A.1); the contact with the paper is line
contact. The detection head shall be parallel to the measuring platform; the degree of
non-parallelism shall not be greater than 0.01 mm.
A.1.3 The test pressure is below 2N.
A.2 Specimen preparation
Take a full-width paper sample from the roll paper. The paper sample shall not be curled
or compressed. Cut 5 paper specimens, along the horizontal direction.
A.3 Test procedure
A.3.1 Adjust the instrument to zero, before testing.
A.3.2 Measurement of corrugated paper thickness: Place the specimen on the measuring
platform. The direction of corrugation is parallel to the detection head (see Figure A.2).
Lower the detection head, to the lowest point of the corrugation. Move the specimen
slightly. Read the lowest value, which is the thickness t of the corrugated paper (see
Figure A.4). The test results are expressed as the average value of 5 specimens.
A.3.3 Determination of corrugation depth: Place the specimen on the measuring
platform. The corrugation direction is perpendicular to the detection head (see Figure
A.3). Put down the detection head. Read the value, which is the full corrugation height
T of the specimen (see Figure A.4). Calculate the corrugation depth according to the
thickness of corrugated paper and the overall corrugation height.
A.3.3.1 Corrugation depth is calculated, according to formula (A.1):
Where:
S - Corrugation depth, in millimeters (mm);
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.