JB/T 8941.2-2014 (JB/T8941.2-2014, JBT 8941.2-2014, JBT8941.2-2014) & related versions
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Roots type blowers for general purpose. Part 2: Performance test methods
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Roots type blowers for general purpose. Part 2: Performance test methods
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JB/T 8941.2-2014
GB
MACHINERY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 23.140
J 72
Registration no.. 45838-2014
Replacing JB/T 8941.2-1999
Roots type blowers for general purpose
– Part 2. Performance test methods
ISSUED ON. MAY 6, 2014
IMPLEMENTED ON. OCTOBER 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 ... 5
4 Symbols, units and subscripts ... 8
5 Measuring method and accuracy ... 9
6 Test method ... 12
7 Comparison between test results and specified values ... 18
8 Test report ... 19
Annex A (Normative) Discharge coefficient and expansibility coefficient ... 20
Annex B (Informative) Steam pressure ... 24
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 2nd 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 8941.2-1999, Roots type blowers for general purpose – Part
2. Performance test methods; and compared with JB/T 8941.2-1999, the main
technical changes of this Part are as follows.
-- in accordance with JB/T 2624.2-2006, it deletes the lengths of orifice plate, grid
type flow conditioner and straight pipe section in the flow measuring device;
-- in accordance with JB/T 2624.2-2006, it modifies the equations and data of
discharge coefficient and expansibility coefficient in Annex A;
-- it adopts GB/T 6075.1-2012, Mechanical vibration – Evaluation of machine
vibration by measurements on non-rotating parts – Part 1. General guidelines,
as the measuring method of vibration;
-- it changes “The volume flow rate of discharge gas of the blower is measured at
the standard discharge points; the flow rate shall be converted to the specified
inlet conditions” into “The volume flow rate of the discharge gas of positive-
pressure blowers (or the inlet gas of negative-pressure blowers) is measured
under the specified discharge pressure of positive-pressure blowers (or the inlet
pressure of negative-pressure blowers)”;
-- it changes “Use calibrated apparatus, e.g. thermometer, thermocouple, electric
resistance thermometer or thermistor with accuracy ± 1 K to insert the pipe or
thermowell to measure temperature” into “The accuracy of the calibrated
apparatus for measuring temperature is ± 1.0°C. The measuring devices include
thermometer, thermocouple, electric resistance thermometer and thermistor”;
-- it adds “g) For the type test of the blower, performance curve and noise spectrum
analysis charts shall be plotted”;
-- it revises part of the words in the original standard.
This Part was proposed by China Machinery Industry Federation.
Roots type blowers for general purpose
- Part 2. Performance test methods
1 Scope
This Part of JB/T 8941 specifies the performance test methods for Roots type blowers
for general purpose (hereinafter referred to as blowers).
This Part applies to the performance test for Roots type blowers for general purpose.
For the blowers which are used under special working conditions and to transfer
special gas, refer to this Standard for the performance test.
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 2624.2-2006, Measurement of fluid flow by means of pressure differential
devices inserted in circular cross-section conduits running full – Part 2. Orifice plates
GB/T 2888, Methods of noise measurement for fans, blowers, compressors and
Roots blowers
GB/T 6075.1-2012, Mechanical vibration – Evaluation of machine vibration by
measurements on non-rotating parts – Part 1. General guidelines
GB/T 8941.1, Roots type blowers for general purpose – Part 1. Specification
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1
standard inlet point
For the representative inlet points specified for each type of blowers, the points change
along with the differences in structure and configuration of blowers
NOTE 1 The standard inlet point of single-stage blowers is at the inlet flange.
NOTE 2 The standard inlet point of double-stage blowers is at the inlet flange of the first-stage
blowers.
NOTE 3 The standard inlet point of packaged blowers is at their inlet starting end.
3.2
inlet condition
the condition that the inlet gas is at the standard inlet point of blowers
3.3
specified inlet condition
the condition of the inlet gas as specified in the product sample or the contract
(temperature, pressure, humidity and gas composition)
3.4
standard discharge point
for the representative discharge points specified for each type of blowers, the points
change with the differences of structure and configuration of blowers
3.5
specified rotational speed
the number of rotations of the shaft of blowers within unit time under the specified
operating conditions
3.6
ambient pressure
the absolute pressure of the atmosphere adjacent to blowers
3.7
inlet pressure
the gas pressure at the standard inlet points, ie. the static pressure of inlet gas
3.8
discharge pressure
the gas pressure at the standard inlet point, ie. the static pressure of inlet gas
3.9
inlet temperature
the stagnation temperature of gas at the standard inlet point
3.10
discharge temperature
the stagnation temperature of gas at the standard discharge point
3.11
ambient temperature
the stagnation temperature of the atmosphere adjacent to blowers but not influenced
by blowers
3.12
actual volume flow rate
the volume flow rate of the discharge gas of positive-pressure blowers (or inlet gas of
negative-pressure blowers) is measured under the specified discharge pressure of
positive-pressure blowers (or inlet gas of negative-pressure blowers); and then it is
converted to the volume flow rate under the standard inlet conditions (temperature,
pressure, humidity and gas composition).
3.13
shaft power
the power required to drive the shaft of blowers, equal to the sum of theoretical power
and mechanical loss, but not including the external driving loss of the devices including
couplers and belt drive
3.14
specific energy
the shaft power required for each unit of actual volume flow rate of blowers
5.2.4 During reading, do not take thermometer from the medium measured. if there
is thermowell, do not take it from its thermowell.
5.2.5 The measures shall be taken to make sure.
a) that the thermal insulation adjacent to insertion points and raised connectors is
good so that the temperatures of thermowell and measured medium are the
same;
b) that the measured medium flow past the sensors or thermometer thermowell of
all kinds of temperature measuring instruments (the sensors or thermometer
thermowells shall be inserted obliquely against the flow. in extreme cases, the
points perpendicular to airflow are allowed);
c) that the thermometer thermowell shall not disturb normal flow.
5.2.6 Thermocouples shall have a welded hot end and shall be calibrated together
with conductor in accordance with their intended application scope. The material of
thermocouples shall be applicable to the temperature of measured medium and use.
If thermocouples have a thermowell, then the hot end shall be welded to the bottom of
thermowell.
5.3 Humidity measurement
Humidity measurement shall be carried out as close to the standard inlet points as
possible, with an aspirated psychrometer of accuracy ± 2%.
5.4 Rotational speed measurement
Use tachometer, photoelectric tachometer or other instruments equipped with a
stopwatch; the accuracy of measuring instruments shall not be lower than ± 0.5%.
5.5 Measurement of flow rate
5.5.1 Use orifice plate measuring device to measure the volume rate of the blower.
The structure and dimensions, service limits and installation requirements of orifice
plate are specified in GB/T 2624.2-2006.
5.5.2 Orifice plate device can be of corner tapping; its structure and dimensions are
specified in GB/T 2624.2-2006.
5.6 Power measurement
5.6.1 Use torquemeter to measure the input power of the blower directly, or obtain
the input power of the blower indirectly by multiplying the output power of motor by
driving efficiency.
6.3.1 Before calculating the measured data, check carefully whether the recorded
data is consistent with the working conditions; the fluctuation of the data measured in
the test shall not exceed the limits in Table 5.
6.3.2 All readings used in the test shall be continuous.
6.3.3 For a group of readings showing a major fluctuation, abandon the readings at
the beginning and end of the test; a group of measured data shall be read at...
......
| Standard ID | JB/T 8941.2-2014 (JB/T8941.2-2014) | | Description (Translated English) | Roots type blowers for general purpose. Part 2: Performance test methods | | Sector / Industry | Mechanical & Machinery Industry Standard (Recommended) | | Classification of Chinese Standard | J72 | | Classification of International Standard | 23.140 | | Word Count Estimation | 17,13 | | Date of Issue | 2014/5/6 | | Date of Implementation | 2014/10/1 | | Older Standard (superseded by this standard) | JB/T 8941.2-1999 | | Quoted Standard | GB/T 2624.2-2006; GB/T 2888; GB/T 6075.1-2012; JB/T 8941.1 | | Drafting Organization | Changsha Blower Factory Co., Ltd. | | Administrative Organization | National Standardization Technical Committee fan | | Regulation (derived from) | Ministry of Industry and Information Technology - Announcement 2014 No 32; Industry standards for filing notice 2014 No. 6 (total 174). | | Issuing agency(ies) | Ministry of Industry and Information Technology of the People's Republic of China | | Summary | This Standard specifies the performance test methods for general purposes Roots blower. This Standard applies to general-purpose performance test Roots blower. In exceptional circumstances, and for transporting special gas blower, can refer to the standar | | Standard ID | JB/T 8941.2-1999 (JB/T8941.2-1999) | | Description (Translated English) | Roots type blowers for general purpose. Part 2: Performance test methods | | Sector / Industry | Mechanical & Machinery Industry Standard (Recommended) | | Classification of Chinese Standard | J72 | | Classification of International Standard | 23.140 | | Word Count Estimation | 15,168 | | Date of Issue | 1999-07-12 | | Date of Implementation | 2000-01-01 | | Older Standard (superseded by this standard) | ZB J72031-1989 | | Quoted Standard | GB/T 2624-1993; GB/T 2888-1991; GB/T 11347-1989; JB/T 8941.1-1999 | | Drafting Organization | Changsha Blower Factory | | Administrative Organization | National Standardization Technical Committee fan | | Regulation (derived from) | Ministry of Industry and Information Technology Bulletin No. 32 of 2014; Industry-Science (2010) No. 77 | | Summary | This standard specifies: Roots blower for general purposes Performance test methods. This standard applies to: general purpose blower (hereinafter referred to as the blower) performance tests. In exceptional circumstances, and for transporting special gases blowers, manufacturer and buyer can negotiate with reference to the standard performance tests. | | Standard ID | () | | Description (Translated English) | (Technical specifications for ceramic capacitive sensor type partial discharge monitoring devices of 35kV and below) | | Sector / Industry | Chinese Industry Standard | | Date of Issue | 2023-10-11 | | Date of Implementation | 2024-04-11 | | Issuing agency(ies) | National Energy Board |
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