JB/T 8941.1-2014 PDF in English
JB/T 8941.1-2014 (JB/T8941.1-2014, JBT 8941.1-2014, JBT8941.1-2014)
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Roots type blowers for general purpose. Part 1: Specification
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| JB/T 8941.1-1999 | English | 239 |
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Roots type blowers for general purpose. Part 1: Specification
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Standards related to (historical): JB/T 8941.1-2014
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JB/T 8941.1-2014: PDF in English (JBT 8941.1-2014) JB/T 8941.1-2014
GB
MACHINERY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 23.140
J 72
Registration no.. 45837-2014
Replacing JB/T 8941.1-1999
Roots type blowers for general purpose
– Part 1. Specification
ISSUED ON. MAY 6, 2014
IMPLEMENTED ON. SEPTEMBER 1, 2014
Issued by. Ministry of Industry and Information Technology of the
People's Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Requirements ... 6
5 Test method ... 10
6 Inspection rules ... 10
7 Marking, packaging and storage ... 11
8 Guarantee period ... 11
Foreword
JB/T 8941, Roots type blowers for general purpose, is divided into two parts.
-- Part 1. Specification;
-- Part 2. Performance test methods.
This Part is the 1st part of JB/T 8941.
This Part was drafted in accordance with the rules given in GB/T 1.1-2009.
This Part replaces JB/T 8941.1-1999, Roots type blowers for general purpose – Part
1. Specification; and compared with JB/T 8941.1-1999, the main technical changes of
this Part are as follows.
-- in Scope, “transfer air and neutral un-toxic gas” is changed into “transfer air, non-
toxic gas, non-explosive gas”; “the air inlet temperature is not higher than 40°C”
is changed into “the air inlet temperature is not higher than 45°C”;
-- in Normative references, “GB/T 13384-1992, General specification for packaging
of mechanical and electrical products” is changed into “JB/T 6444, General
specifications for packaging of fans, blowers and compressors”;
-- it adds the definition of “standard volume flow”;
-- it changes “The service life is not less than 10 years” into “The service life is not
less than 15 years”;
-- it changes “The service life of synchromesh gear is not less than 25 000 h in
design” into “The service life of synchromesh gear is not less than 40 000 h in
design”;
-- it changes “The accuracy of synchromesh gear is not lower than grade 7-7-7 as
specified in GB/T 10095” into “The accuracy of synchromesh gear is not lower
than grade 6 as specified in GB/T 10095.1 to GB/T 10095.2-2008”;
-- it adds “For blowers with impeller of diameter greater than 750 mm, temperature
measurement device shall be provided at the position of bearing when forced
lubrication is used for bearing”;
-- it adds “There shall be safety warnings when the surface temperature of blowers
and accessories exceeds 80°C”;
Roots type blowers for general purpose
Part 1. Specification
1 Scope
This Part of JB/T 8941 specifies the terms and definitions, requirements, test method,
inspection rules, marking, packaging, storage and guarantee period of roots type
blowers for general purpose (including single-stage, double-stage and package
blowers of positive- and negative-pressure).
This Part applies to roots type blowers for general purpose (hereinafter referred to as
blowers) which are used to transfer air and neutral non-toxic, non-explosive gas. The
air inlet temperature of blowers is not higher than 45°C; the content of solid particles
in gas is not greater than 100 mg/m3; the maximum size of particles is not greater than
half of the minimum working clearance of all relative movement parts in the air cylinder
of blowers.
2 Normative references
The following documents are indispensable for the application of this document. For
dated references, only the dated editions apply to this document. For undated
references, their latest editions (including all amendments) apply to this document.
GB/T 2888, Methods of noise measurement for fans, blowers, compressors and
roots blowers
GB/T 10095.1-2008, Cylindrical gears – System of accuracy – Part 1. Definitions
and allowable values of deviations relevant to corresponding flanks of gear teeth
GB/T 10095.2-2008, Cylindrical gears – System of accuracy – Part 2. Definitions
and allowable values of deviations relevant to radial composite deviations and
runout information
GB/T 13306, Plates
GB/T 6444, Mechanical vibration - Balancing vocabulary
GB/T 8941.2, Roots type blowers for general purpose – Part 2. Performance test
method
4.1.3 The accuracy of synchromesh gear of blowers is not lower than grade 6 as
specified in GB/T 10095.1 to GB/T 10095.2-2008.
4.1.4 It shall be ensured that the lubrication of synchronous gear and bearing of
blowers is reliable.
4.1.5 Shell and wall panel of blowers shall be of one-piece or split-up-and-down
structure, in order to ensure the shell and wall panel can be aligned conveniently and
correctly in reassembly.
4.1.6 Impeller and shaft can be of one-piece structure or other structure to connect
together, but any loosening between the two is not allowed.
4.1.7 For blowers with impeller of diameter greater than 750 mm, temperature
measurement device shall be provided at the position of bearing when forced
lubrication is used for bearing.
4.1.8 Drive system of blowers shall be provided with reliable safety measures.
4.1.9 There shall be safety warnings when the surface temperature of blowers and
accessories exceeds 80°C.
4.1.10 Check value or other device shall be generally installed in the gas exhaust
piping of blowers, in order to prevent the gas at the outlet of blowers flowing back or
the rotor of blowers being reversed abnormally.
4.1.11 Pressure release valve shall be provided at the outlet of blowers (or the inlet
of negative-pressure blowers) in accordance with the operating requirements of the
device.
4.1.12 Proper sound elimination and sound insulation devices shall be selected in
accordance with the requirements of the service environment on noise.
4.2 Performance requirements
4.2.1 The deviations between volume flow, energy volume ratio and design volume
flow, energy volume ratio of blowers (excluding packaged blowers) shall not exceed
the values specified in Table 1.
Table 1 – Allowable deviations of volume flow and energy volume ratio
Volume flow under design
conditions
m3/min
Deviation between measured and
design volume flows
Deviation between measured and
design energy volume ratio
≤ 0.5 ± 7 + 8
> 0.5 to 1.5 ± 6 + 7
4.4 Assembling requirements
4.4.1 The parts of blowers shall be inspected by the quality department of the
manufacturer; the outsourced parts shall be provided with compliance certificate or
quality certificate, which shall be inspected by the manufacturer; the parts can be
assembled after washing and the oil-way becomes unblocked.
4.4.2 Accurate and reliable mounting and good interchangeability shall be ensured
for gear.
4.4.3 The clearance between driving impeller and driven impeller of blowers, the
clearance between impeller and shell, and the clearance between impeller end face
and wall panel shall be as specified in the drawings.
4.4.4 The joint of the exposed parts of blowers shall be smooth. The alignment
tolerances for the joint of shell and wall panel, the joint of split shell and wall panel and
the joint of wall panel and fuel tank shall not exceed the specifications of Table 2.
Table 2 – Alignment tolerance limits
Nominal diameter of inlet and outlet of blowers Alignment tolerance limit
≤ 200 3
> 200 to 350 4
> 350 5
4.4.5 Checking positions for the cleanliness degree of blowers.
a) gear box (main oil tank). including oil tank cavity, gear and other parts in gear
box. If gear box also works as oil tank, lubrication oil is also included;
b) auxiliary oil tank. including oil tank cavity and lubrication oil;
c) bearing assembly. including bearing seat, bearing cap inner wall, bearing and
lubrication oil (grease).
4.4.6 Checking method for the cleanliness degree of blowers.
Take apart the detachable part of the product designated to be the object of checking;
use a clean brush and gasoline (or kerosene) to clean the positions required to be
checked piece by piece; use filter water to filter the washings; dry them; weigh foreign
matter separately. the milligrams of the foreign matter is the cleanliness degree of the
part.
4.4.7 The cleanliness degree of blowers is specified in Table 3.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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