Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T7674-95
Roots Vacuum Pump
Published on June 16, 1995
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1996
Mechanical Industry Standard of the People's Republic of China
Roots Vacuum Pump
Subject Content and Scope of Application
JB/T7674-95
ZBJ78013-89
This standard specifies the types and basic parameters, technical requirements, test methods and inspection rules, marking, packaging, transportation and storage of Roots vacuum pumps.
This standard is applicable to single-stage double-blade Roots vacuum pumps (hereinafter referred to as pumps) with a pumping speed of 30 to 20,000 L/s and a fore-stage pump when working. Reference standards
GB6070
GB/T13306
JB/T5973
JB/T7266
Types and basic parameters
Model representation method
Packaging, storage and transportation graphic symbols
Vacuum flange
Simple method for determination of sound power level of dryer noise Performance measurement method of vacuum pump
Pumping rate, L/s
Roots vacuum pump type, see Table 1
Roots vacuum pump, represented by ZJ
3.2 Marking example
Roots vacuum pump with a pumping rate of 1200L/s is marked as: ZJ-1200
Roots vacuum pump with a pumping rate of 300L/s with a bypass valve is marked as: b.
ZJP-300
3.3 Basic parameters
The basic parameters should comply with the requirements of Table 2.
Approved by the Ministry of Machinery Industry on June 16, 1995
With bypass valve
Implemented on July 1, 1996
JB/T7674-95
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5.1.2.2 Vacuum gauge
0.26~1.10
65~260
JB/T7674-95
Select vacuum gauges of different types and accuracies according to the measured pressure. V,
When the measured pressure is higher than or equal to 0.1Pa, its calibration accuracy is within ±5%. When the measured pressure is lower than 0.1Pa, its calibration accuracy is within ±10%. D
5.1.2.3 Flow meter
Select flow meters of different types and specifications according to the measured flow. It is generally recommended to use a dropper flowmeter, but a float flowmeter can also be used when the flow rate is too large. The flowmeter must be calibrated by the measurement department to ensure that its accuracy meets the specified requirements: the flow rate is greater than 1W within ±3%; the flow rate is between 110-*W within ±5%; the flow rate is less than 10-*W within ±10%.
Note: 1W=1Pa·m\.s-1
When using a dropper flowmeter to measure gas flow, oil with low saturated vapor pressure and low viscosity should be selected. 2\ transformer oil is recommended. 5.1.2.4 Other instruments
Other instruments such as barometers, tachometers, power meters, sound level meters, stopwatches, etc. should all comply with the relevant standards. 5.1.2.5 Foreline pipeline and test cover on the pipeline The pipeline between the outlet of the Roots pump to be measured and the foreline pump should be designed and manufactured according to Figure 2. The test cover on the pipeline should be designed and manufactured according to Figure 1a. 5.1.2.6 Device
The measuring device of Roots vacuum pump is shown in Figure 3. 5.1.3 Measurement of ultimate pressure of pump
The pump is operated under the specified conditions and tends to the lowest stable pressure in the test hood without introducing gas. 5.1.3.1 Measurement steps
The device is shown in Figure 3. Close the fine-tuning valve and start the pump to make it run smoothly (usually after 15 minutes). Then the pressure can be measured with a vacuum gauge. Measure the pressure every 5 minutes. When the results of three consecutive measurements show that the pressure no longer decreases, the ultimate pressure is reached. The measured ultimate pressure is expressed in two significant figures. Test cover for pipe connection
a+b=5D
Figure 2 Fore stage pipeline
Fore stage pump inlet diameter
JB/T7674--95
Figure 3 Measuring device
1-Roots vacuum pump; 2-Electric motor: 3-Vacuum gauge; 4-Test cover; 5-Fine adjustment valve; 6-Flow measuring device; 7-Power meter; 8-Fore stage pipeline: 9-Test cover on pipeline; 10-Fore stage pump 5.1.4 Measurement of pumping rate
5.1.4.1 Principle
The pumping rate of the pump is measured by the "constant pressure method". That is, the pressure in the test cover remains unchanged during the flow measurement process. 5.1.4.2 Measurement steps
The pumping rate measuring device is shown in Figure 3. In order to measure the pumping rate, the test cover, vacuum gauge and flow meter should be connected to the pump. Close the fine-tuning valve, start the pump, and after the pump runs stably and reaches the limit pressure, open the fine-tuning valve, introduce the test gas into the hood, establish a set equilibrium pressure, measure its pressure value with a vacuum gauge, and measure the gas flow with a flowmeter. Calculate the pumping rate according to JB/T7266. The measurement should start from an appropriate pressure value close to the limit pressure, and measure at least three points for each order of magnitude (the distribution basically conforms to 2.5, 5, and 10). If the flow measurement time is long, take 60$ as a cycle, the pressure should be measured repeatedly, and the average value should be taken. If the difference between the highest and the lowest is greater than 10% of the average value, both the flow and pressure should be remeasured. 5.1.5 Measurement of the maximum allowable pressure difference
The maximum allowable pressure difference refers to the maximum value of the difference between the outlet pressure and the inlet pressure allowed when the pump inlet pressure is lower than 1×.10°Pa, and it runs continuously for 40 minutes without failure.
5.1.5.1 Measurement steps
Introduce room temperature dry air into the suction side of the pump and the front vacuum pipeline, adjust the air inlet valve to make the inlet pressure lower than 1×10\Pa, and adjust the pressure of the test cover on the front pipeline accordingly. A series of pressure differences are generated between the outlet and inlet sides of the pump, and the largest pressure difference is the maximum allowable pressure difference. The pump must ensure trouble-free operation for 40 minutes under this pressure difference. The measurement results are expressed in two significant figures. 5.1.6 Measurement of power consumption
5.1.6.1 The power consumption of the pump is expressed by the output power of the motor. It is equal to the input power of the motor multiplied by the efficiency of the motor. Nconsumption=Ninput\motor
Where: Nconsumption-the power consumption of the pump, kW; Ninput-the input power of the motor, kW;
7motor-the efficiency of the motor, %.
5.1.6.2 The input power measurement of the motor should use an instrument with an accuracy of not less than 0.5 level, and it must be verified by the metrology department. 5.1.6.3 The power consumption measurement of the pump can be carried out simultaneously with the measurement of the pumping rate. 5.1.7 Measurement of the maximum compression ratio Komx at zero flow rate 5.1.7.1 The compression ratio K when the gas flow rate is zero. It is the ratio of the pressure in the fore-stage vacuum pipeline to the inlet pressure of 5
JB/T7674-95
when the intake pipeline is closed and the gas flow rate is zero. The maximum value of this compression ratio is represented by Kmx. The test gas is a non-condensable gas, generally referring to air. 5.1.7.2 Basic principle
The measurement method is to install a test cover on the pump inlet, close the intake valve, and then adjust different pressures on the fore-stage vacuum side by appropriate means (such as inflation).
5.1.7.3 Measuring device
As shown in Figure 3.
5.1.7.4 Measurement procedure
Close the fine adjustment (5)) (see Figure 3), and by adjusting the air inlet valve of the pipeline test cover, different amounts of gas are put in, and different pressures are formed in the test cover (9). Use a vacuum gauge to measure the pressure in the test cover (4) and the test cover (9) respectively, and you can get a series of zero-flow compression ratio K values.
The measurement is valid only when the change in the pressure readings measured twice in 15 minutes is no more than 5%. 5.1.8 Pump noise measurement
5.1.8.1 The pump noise measurement shall be in accordance with JB/T5973. 5.1.8.2 Measure the noise of the pump without the test cover at the limit pressure. When measuring, stop the front stage pump. 5.2 Inspection rules
5.2.1 Each pump must be inspected and can only be shipped after passing the inspection. 5.2.2 Pump inspection is divided into factory inspection and type inspection. 5.2.2.1 Factory inspection
Ultimate pressure;
b. The pump is tested for continuous operation under the ultimate pressure. For pumps with a pumping speed S>1200L/s, the time is not less than 4h, and for pumps with a pumping speed S≤1200L/s, the time is not less than 2h.
5.2.2.2 Type inspection
5.2.2.2.1 Type inspection should be carried out in any of the following situations: a.
When trial-producing new products;
b. When there are major changes in the design, process or materials of the pump that may affect the performance of the pump; c. When the pump is mass-produced.
5.2.2.2.2 Contents of type inspection: ultimate pressure, pumping speed, maximum allowable pressure difference, maximum compression ratio at zero flow, noise measurement, and continuous operation test. The method of type inspection shall be carried out in accordance with the provisions of Article 5.1.35.1.8 of this standard. 5.2.2.2.3 For type inspection, 5% of each batch shall be sampled, but not less than 2 units; if the sample fails to meet the standard, double sampling shall be conducted. If the sample fails again, the batch of products shall be inspected one by one.
6 Marking, packaging, transportation and storage
6.1 Each pump shall be marked with a product label in a conspicuous position, and its size shall comply with the provisions of GB/T13306. It shall indicate: pump model and name;
Manufacturer's name:
Pump technical parameters: ultimate pressure (Pa), suction speed (L/s) c.
d. Pump number and manufacturing date.
6.2 Each pump shall be marked with the "steering" symbol and the words "water inlet", "water outlet", "refueling", "oil draining" etc. in the corresponding position. 6.3 The pump shall be packed in boxes when leaving the factory, and the inlet and outlet must be sealed. Spare parts and technical documents must be included with the machine and should be properly placed in the box to avoid loss or damage during transportation.
6.4 The packaging of the pump shall comply with the provisions of GB191. The following clear words and marks shall be on the outside of the packaging box: a. Name of the manufacturer, name of the pump, model and number of the pump; b. Name and address of the consignee;
JB/T7674-95
Packing size and weight, a total of × boxes, and words such as "handle with care" and "do not invert", and the large pump shall be marked with "lifting position"; c.
The markings on the packaging box shall not be blurred due to severe rain erosion or long-term use. 6.5 The pump shall be accompanied by the following documents when leaving the factory:
Packing list;
Product certificate;
Product instruction manual.
7 Measurement records
7.1 Record the performance parameters and test conditions of the pump 7.1.1 The performance parameters of the pump include: ultimate pressure, suction rate, speed, maximum allowable pressure difference, etc. 7.1.2 Test conditions include: the matching fore pump, room temperature, atmospheric pressure, the type of vacuum gauge used, the type of flow meter used, ambient temperature, other instruments, meters, cooling conditions, etc. 7.2 Record test data and calculate test results 7.2.1 When measuring the ultimate pressure, the ultimate pressure and the corresponding power consumption should be recorded. 7.2.2 When measuring the pumping rate, the inlet pressure, the suction gas flow, the power consumption, the pumping rate, the pump speed, and the corrected pumping rate should be recorded.
7.2.3 When measuring the maximum allowable pressure difference, the inlet pressure, the outlet pressure, and the power consumption should be recorded. 7.2.4 When measuring the maximum compression ratio Km at zero flow, the inlet pressure, the outlet pressure, and the maximum compression ratio Kmx at zero flow should be recorded. 7.3 Draw curves based on test calculations
Draw the relationship curve between the pumping rate and the inlet pressure, that is, the Sp curve. 7.3.1
Draw the relationship curve between the power consumption and the inlet pressure, that is, the N-force curve. 7.3.2
Draw the relationship curve between flow rate and inlet pressure, i.e. Qp curve. 7.3.3
Draw the relationship curve between zero flow compression ratio and inlet pressure, i.e. Koex-curve. 7.3.4
Additional remarks:
This standard is proposed by the National Technical Committee for Vacuum Technology Standardization. This standard is under the jurisdiction of Shenyang Vacuum Technology Research Institute of the Ministry of Machinery Industry. This standard is drafted by Shenyang Vacuum Technology Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Zhang Shufan and Li Yuying. This standard was first issued in 1977.
This standard was first revised in 1989.
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