JB/T 3344-1993 Condenser performance test procedures

This standard specifies the performance test method for steam turbine condensers to determine the following performance indicators of condensers. a. Thermodynamic characteristics of the condenser under design conditions (exhaust volume, cooling water wash volume, cooling water inlet temperature, and overall cleanliness factor are all design values); b. Thermodynamic characteristics of the condenser under variable conditions; c. Subcooling of the condenser condensate; d. Oxygen content of the condenser condensate; e. Condenser water resistance characteristics. This standard applies to the performance test of steam turbine surface condensers. JB/T 3344-1993 Condenser Performance Test Procedure JB/T3344-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T3344-1993
Condenser
Published on August 21, 1993Www.bzxZ.net
Performance Test Procedure
Implemented on October 1, 1993
Mechanical Industry Standard of the People's Republic of China
Condenser
Subject Content and Scope of Application
Performance Test Procedure
This standard specifies the performance test method for steam turbine condenser to determine the following performance indicators of condenser: 8
JB/T3344-1993
Replaces JB3344-83
Thermodynamic characteristics of condenser under design conditions (exhaust volume, cooling water flow, cooling water inlet temperature, and overall cleanliness factor are all design values";
Thermodynamic characteristics of steam escape device under variable conditions; subcooling of condenser condensate;
Oxygen content of condenser condensate;
Water resistance characteristics of condenser.
This standard applies to performance tests of surface condensers of steam turbines. 2
Referenced standards
GB 2624
Flow measurement throttling device
Name, symbol and unit
Name, symbol and unit are shown in Table 1.
Condenser heat load
Exhaust volume
Condenser pressure
Condenser inlet pressure
Steam condensing temperature
Condensate turbidity
Condensate subcooling
Condensate flow
Exhaust steam specific temperature
Condensate specific temperature
Cooling water inlet temperature
Cooling water outlet temperature| |tt||Cooling water overflow
Total heat transferred to cooling water per unit time
Steam flow rate discharged from steam turbine to condenser
Absolute pressure (static pressure) of steam entering condenser near the first row of tube bundles (one stream is 300mm away from the first row of tube bundles)
Absolute pressure (static pressure) of steam at the condenser inlet sectionSteam saturation temperature corresponding to condenser pressureTemperature of condensate entering condenser hot wellDifference between steam condensation plasticity and condensate overflowAmount of condensate discharged from condenser per unit timeRatio of steam discharged from condenser by steam turbine| |tt||According to the condensing water temperature t. Check the steam table
The temperature of cooling water at the inlet of the condenser [or sample tube] The temperature of cooling water at the outlet of the condenser (or sample tube) The difference between the outlet and inlet temperatures of cooling water
Approved by the Ministry of Machinery Industry on August 21, 1993
Implemented on October 1, 1993
Specific heat capacity of cooling water
Initial temperature difference
Terminal temperature difference
Logarithmic mean temperature difference
Condenser area
Overall heat transfer coefficient
After correction Overall heat transfer
Initial temperature difference of sample tube
Terminal temperature difference of sample tube
Area of ​​sample tube
Heat transfer coefficient of sample tube
Heat transfer coefficient of new tube
Heat transfer coefficient of old tube
Number of sample tubes
Cleanliness coefficient
Speed ​​index of cleanliness coefficient
Water flow rate of cold part
Single sample and cooling water flow
Cooling water density
Inlet water pressure
Outlet water pressure
Condenser water resistance
Air outlet coverage|| tt||JB/T3344-1993
refers to the average temperature and specific heat capacity of cooling water under the condition of fixed salt content during the test period. The difference between the steam condensation temperature (t) and the cooling water inlet temperature (t1). The difference between the steam condensation temperature (t) and the cooling water outlet temperature (tz). The integral average value of the temperature difference in the heat transfer process between steam and cooling water in the condenser. The effective surface area of ​​all cooling tubes in the condenser (the effective area does not include the area of ​​the tubes blocked during the test).
The heat transferred by the condenser per unit time, per unit area, and per degree logarithmic mean temperature difference. Quantity: Overall heat transfer coefficient corrected according to the average water velocity, average temperature and average cleanliness factor under contractual conditions or test conditions.
Difference between steam condensation temperature (ts) and cooling water inlet temperature (ti) of sample tube. Difference between steam condensation temperature (t,> and cooling water outlet temperature (t) of sample tube. Effective surface area of ​​a sample tube.
Heat transferred by the sample tube per unit time, per unit area, per degree under logarithmic average overflow difference. When determining the cleanliness factor, the heat transfer coefficient of the new test sample tube. When determining the cleanliness factor, the heat transfer coefficient of the old test sample tube. The number of new test sample tubes is expressed by N, and the number of old test sample tubes is expressed by N. It indicates the correction factor for taking into account the uncleanliness of the cooling surface when calculating the actual heat transfer coefficient. It is the ratio of the heat transfer coefficient of the old tube to the heat transfer coefficient of the new tube under the same operating conditions. The change in the cleanliness coefficient is approximately inversely proportional to the mth power of the water velocity in the tube. The cooling water flow rate through the steam generator per unit time. The cooling water flow rate through a single test sample tube per unit time is obtained according to the inlet temperature and salt content of the cooling water during the test (see Appendix A). The average value of the water velocity in the tube
The static pressure of cooling water at the water chamber inlet
The static pressure of cooling water at the water chamber outlet
The pressure loss of cooling water when it flows through the condenser, which includes the water chamber loss, tube end loss, and loss in the cooling tube. The difference in elevation between the two measuring points of the cooling water inlet and outlet and the correction of the velocity head should be considered in the calculation. Temperature of the steam-gas mixture at the condenser exhaust port (i.e., on the single gas pipeline) Unit
kJ/(kg·)
W/(mc)
W/(m+C)
Air outlet pressure
Condenser steam resistance
Main steam flow
Main steam ratio
Extraction volume of each section
Extraction ratio of each section
Output power
Heat loss of steam turbine unit
JB/T3344—1993
Continued Table 1
Pressure of the steam-gas mixture at the condenser exhaust port (static pressure) Pressure loss between steam inlet and air exhaust port (Pr-P .) Main steam flow entering the turbine
Ratio of main steam entering the turbine
Extraction volume of each section
Extraction ratio of each section
For power generation, it refers to the power at the output end of the generator; for driving, it refers to the output power on the coupling connecting the driven machinery
Including units such as mechanical loss, radiation loss, and motor loss
Note: 1) When the pressure drop △Pk of steam from the condenser inlet cut to the first row of tube bundles is ignored, then Ps=P. If an extraction pipe or low-pressure heater is arranged between the condenser inlet cut to the first row of tube bundles, the pressure drop △P should be taken into account. At this time, PpP—△Pk·2》The sample tube is the test sample tube,
4 Guidelines
The specific items of the condenser performance test are determined by the test purpose. 4.1
4.2 Before the test, the operating conditions of the main engine and condenser should be fully understood, and the various pipelines and equipment related to the device used in this test should also be familiarized.
4.3 Before the test, the various parameters that affect the test results should be kept stable for at least half an hour, such as the main steam, reheat steam temperature, main steam pressure, turbine power, cooling water flow, etc. The operating conditions of the main engine reheat system and condenser should remain stable during the test. The requirements are shown in Table 2. However, in any case, the allowable variation range of pressure and temperature specified by the manufacturer cannot be exceeded. 4.4 In order to obtain a stable condenser load, the power limiter can be adjusted to fix the opening of the regulating valve, and the synchronizer can be shaken in the negative direction. After adjustment, it must be ensured that the valve can be closed normally to prevent accidents. 4.5 The instruments and accuracy used in the test should be determined in advance according to this standard and test requirements. Various instruments and meters need to be calibrated and checked, and can only be used after being confirmed as qualified by relevant parties. If necessary, they should be recalibrated immediately after the test. The choice of measurement method can be determined according to the test conditions and requirements.
4.6Before the test, except for the steam turbine exhaust, all other drain water, make-up water and water seal return water (or steam) entering the condenser should be cut off. For some that cannot be cut off, the various amounts of water (or steam) entering the condenser should be considered in the compilation of the test results. The measurement and calculation methods of this amount should be specified in advance. Table 2
Variable name
Main steam pressure
(absolute pressure)
Main steam temperature
Reheat steam temperature
Electric power
Cooling water inlet temperature
Cooling water flow
Maximum allowable deviation between the test mean value and the specified value ±3%
±15℃
Maximum allowable deviation of the variable from the mean value during any test ±2%
±4℃
±1℃
JB/T3344-1993
4.7 In addition to making some adjustments in the test only for the requirements (such as Section 4.6), the condenser should be in the normal operation state of commissioning. 4.8 This test should have strict restrictions on the amount of air leaking into the unit vacuum system. The maximum amount of air allowed to leak into the system should be specified. The test can only be carried out if the following requirements are met. Confirm that the vacuum tightness of the unit is within the specified range. The permissible range of the vacuum system tightness should be determined according to the requirements put forward by the manufacturer: if the manufacturer does not clearly specify, it can be determined by referring to the requirements of Table 3. Table 3
Unit capacity
100~200
Note, the vacuum drop rate here should be the value measured when the unit load is greater than 80% of the rated load, the following
Pa/min
Before the test, the leakage of cooling water must be limited, and try to avoid leakage. If the amount of cooling water leaking into the steam space exceeds the specified value (based on the test accuracy and the water quality requirements of the power plant), the test cannot be carried out. Before the test, all kinds of garbage and microorganisms accumulated on the cooling water inlet pipe and the condenser water chamber tube plate should be removed. 4.10
Before the test, the condenser tubes should be fully cleaned to achieve the cleanliness level of the unit in the initial operation. 4. 11
The cleanliness factor of the condenser must be determined by test. If the unit meets the requirements of Article 6.6 of this standard, the cleanliness factor can be determined as 1.4.12
4.13~If the measurement of the cleanliness factor is omitted in general tests, the value of the cleanliness factor can be calculated according to Article 7.13.2 of this standard or determined through consultation with relevant units.
4.14 The measurement and calculation method of the cooling water flow before the test, and the deviation of the cooling water flow, should be determined through consultation with relevant units. 4.15 The test process should maintain stable working conditions. After the unit reaches stable working conditions, all readings should be observed and recorded in a short period of time before the official reading of this working condition. The test can only be carried out after confirming that the stable test working conditions have been reached. 4.16 Preliminary tests should be conducted for the following purposes: 1.
Check various instruments: 2.
Train test personnel: 3.
Check the adaptability of the entire test device, and make some minor appropriate adjustments according to the test situation; c.
Equipment isolation inspection. 4.17 After the completion of the preliminary test conditions, if the test meets the conditions and the results meet the requirements, it can also be used as a formal test condition with the consent of the relevant units. 4.18 When processing or calculating a certain condition, first find out the reliability and consistency of each measurement value. When serious contradictions occur in the data, the test values ​​of this condition should be partially or completely abolished, and the test should be repeated if necessary. 4.19 The time for testing each condition should be continuous and long enough to ensure the accuracy and consistency of the test results, which is usually Th for each condition.
4.20 Reading requirements
When testing one working condition for 1 hour, the cooling water temperature is read every 2.5 minutes, and other readings are read every 5 minutes: a.
All kinds of data in each working condition of the test should be read at the same time; for data not involved in the test calculation but related to the working condition, only two readings at the beginning and end of each working condition need to be recorded; e.
4.21 Error: The error of various measured values ​​should be explained in the test report. For some data that cannot be accurately measured, the error range is required to be indicated. Only the data obtained in accordance with the test observation requirements are calculated for error; the allowable value of error should be agreed with the relevant units. Instruments and measurement methods
5.1 Pressure measurement
JB/T3344--1993
5.1.1 Measurement of condenser inlet pressure and condenser pressure. The condenser inlet pressure and condenser pressure should be the average static pressure value on the measuring section. During measurement, one pressure sensing hole is usually connected to one pressure gauge.
b. Measurement section: The condenser steam inlet section close to the first row of condenser tube bundles is the condenser pressure measurement section, which is usually taken as about 300mm away from the first row of tube bundles. The condenser inlet cross section is the measuring cross section of the condenser inlet pressure. For the horizontally arranged suspended condenser, it can be on any side near the connection between the turbine exhaust port and the condenser. For other forms of condensers (used for lateral exhaust, full-circle exhaust, etc.), it is difficult to determine the position of the condenser inlet cross section. In principle, the steam inlet section as close as possible to the first row of condenser tube bundles can be taken as the condenser inlet cross section.
c, pressure sensing hole: The static pressure on the condenser measurement cross section is extremely uneven. In order to obtain the average pressure on the condenser measurement cross section, multiple pressure measuring points must be arranged. Generally, pressure measuring rods are drilled around the throat perpendicular to the inner surface of the side wall. The hole diameter is about 10mm and must not be less than 6mm. The wall surface α300mm around the hole should be smoothed and polished. If the location and structure of the throat make it impossible to drill a wall hole or the pressure measured by the side wall hole is not representative, the built-in pressure measuring device shown in Figure 1 can be used. The built-in pressure measuring device is installed at a specific position of the throat or at the center of the equally divided area. No matter which built-in sensing head is installed, it must be insensitive to the direction of the airflow and acceptable to all parties involved in the test, and it must be described in detail in the test report.
If the pressure distribution on the measuring section is unknown, the total number of required measuring points must be determined based on the principle of not less than one measuring point per 1.5 exhaust area. If the number of measuring points is to be reduced, the pressure distribution on the measuring section must be known, and the pressure sensing head is arranged on the isobaric line of the average static pressure of the section. In this way, the total number of measuring points can be reduced to no more than 8, but not less than 2. d. When making the overall arrangement of the measurement system, the pressure gauge should be higher than the pressure transmission pipe, and the pressure transmission pipe should be higher than the sensing hole, so that the measurement system can automatically drain water to the condenser. Otherwise, the measurement system must be specially designed for sufficient drainage. If the design of the automatic drain system is indeed difficult, it is necessary to negotiate and choose a method to prevent water from accumulating in the pressure transmission pipe, such as effective air flushing, etc.
e. Measuring instrument: The pressure of the steam boiler is measured by a mercury manometer or a precise vacuum gauge in combination with a barometer. The scale reading of the meter should be accurate to 34Pa. The mercury in the mercury manometer should be pure. 5.1.2 Air outlet pressure
The mercury manometer is used to measure the air outlet pressure. A meter should be installed in each conduit from the condenser to the vacuum pump. These meters should be as close to the condenser as possible.
5.1.3 Tightness of the measurement system
The tightness of the measurement system should be checked before the test. When the cut-off valve near the sensing hole is closed under the specified vacuum degree, the vacuum drop rate shall not exceed 800Pa every 5 minutes on average.
5.1.4 Atmospheric pressure
In order to convert the indication value of the pressure gauge and manometer into absolute pressure, an accurate local atmospheric pressure value must be measured using a glass mercury barometer. The barometer should be at the same height in the same place as the pressure gauge or manometer, otherwise the measured value should be corrected:
5.1.5 Barometer
The barometer must be a precision barometer (error is less than ±20Pa). If there is any doubt about the accuracy of the barometer used, the barometer must be sent to the meteorological station or relevant laboratory for calibration.
JB/T3344-1993
DN20 thick-walled stainless steel pipe
80-01.6 Arranged along the spiral line
No. 6 or No. 7 metal wire mesh (wire diameter @1.65) cage probe
Pressure transmission pipe||t t||b Guide plate static pressure probe
Figure 1 Built-in pressure measuring device
5.1.6 Correction of recorded readings
JB/T3344-1993
The recorded readings during the test period should be averaged and the following correction calculations should be made: During pressure measurement, when the pressure transmitter is filled with water (or other media), the height difference between the pressure gauge and the measuring point must be corrected. When the pressure gauge is higher than the measuring point, the correction value is positive, and when the pressure gauge is lower than the measuring point, the correction value is negative: All calibrated pressure gauges must take into account the calibration correction value of the instrument; the readings of liquid pressure gauges and glass mercury barometers must also be corrected as follows, a. Ambient temperature
Convert the temperature of the scale and the column to 0℃; b. Capillary effect
When the diameter of the single-tube mercury pressure gauge is less than 12mm, the capillary effect must be corrected: c. Gravitational acceleration
The local gravity acceleration where the instrument is located must be converted to the international standard value; d. Altitude
The significant altitude difference between the barometer and the liquid pressure gauge must be corrected. This correction should be made after the barometer is corrected for ambient temperature, gravity acceleration and instrument calibration.
5.1.7 Aerator working pressure
0.4 grade standard pressure gauge can be used to measure the working steam pressure (steam jet aspirator) or working water pressure (water jet aspirator) of the aspirator. The measuring point should be as close to the equipment as possible. When in use, the pressure gauge should be protected by a water ring pipe to prevent the gauge from being directly affected by hot steam 5.1.8 Water resistance
When measuring water resistance, each flow-following water pipe shall have at least one differential pressure gauge, generally a mercury pressure gauge. The inner diameter of the inlet and outlet water pipes connected to the differential pressure gauge shall not be less than 12mm. The pressure pipes from the inlet water pipe to the outlet water pipe are all continuously upward. The balance pipe valve between the two pressure pipes is opened to ensure that the pressure pipe is filled with water and exhausts air. When measuring, close this valve to stop the flow of water. At this time, the difference in mercury columns on the differential pressure gauge is the water resistance.
5.2 Temperature measurement
5.2.1 Cooling water temperature
a. Glass mercury thermometers are used to measure the inlet and outlet water temperatures of the condenser water chamber. These thermometers should be of secondary standard 0.1C scale. The thermometer should be inserted into the oil-filled thermometer sleeve. The depth of the thermometer inserted into the water pipe is about one-fifth of the diameter of the water pipe. A naked thermometer with appropriate metal mesh protection can also be used. When it is difficult to use a mercury thermometer, a resistance thermometer can be used with a precision bridge for measurement. b. Each cooling water inlet pipe should have a secondary standard mercury thermometer to measure the temperature: a temperature sleeve can be inserted into the water pipe for measurement, or sample water can be continuously taken out from the water inlet pipe and measured with a naked glass thermometer. The overflow of the cooling water outlet pipe is distributed in layers. In order to obtain the average temperature on the cross-section to be measured, a water overflow sampler (such as a flute for extracting sample water) and a temperature sensing element (combined thermocouple) are generally arranged in at least two diameter directions on each outlet pipe. Generally, there is at least one sampling point or temperature sensing element on an area of ​​0.2mm, and the surface should be arranged at the center of the equally divided area. The measuring point should be arranged on the pipe about 3m away from the cooling water outlet of the condenser as far as possible. 5.2.2 Condensate temperature and air outlet temperature A secondary standard mercury thermometer or resistance thermometer with a scale of 0.1℃ can be used to measure the condensate temperature t and the steam-air mixture outlet temperature t. The sleeve of the condensate thermometer should be filled with oil. The thermometer for measuring the temperature of the steam-air mixture can be directly inserted into the mixed gas through a wedge-shaped rubber stopper
5.2.3 The drain temperature and working water temperature of the vacuum pump A secondary standard mercury thermometer with a scale of 0.1℃ can also be used to measure the drain temperature and working water temperature of the vacuum pump. 5.2.4 The working steam temperature of the vacuum pump
A mercury thermometer, thermocouple or resistance thermometer can be used to measure the working steam temperature of the vacuum pump. 5.2.5 Precautions in temperature measurement
&. The inner diameter of the temperature sleeve should be as small as possible, and the pipe wall should be as clean as possible; 7
JB/T3344-1993
b. The heat exchanged with the temperature measuring sleeve by conduction or radiation from the outside of the measured medium should be minimized; c. When the inner diameter of the pipeline is less than 75mm, the sleeve should be inserted into the pipeline along the axial direction at the elbow or tee. Where there are no elbows and tees available, appropriate changes must be made to the pipe layout. When the inner diameter of the pipeline is greater than or equal to 75mm, in principle, the center of the temperature sensing element should be located on the center line of the pipeline, except for extra-large-sized pipelines and special temperature measuring devices. The insertion depth of the sleeve in water should not be less than 80mm, and the insertion depth in steam should not be less than 150mm; d. When measuring the temperature of the flowing medium, the temperature sleeve should be inserted in the direction of the fluid flow, or at least perpendicular to the flow direction. It must not be inserted along the flow direction or in a dead zone without flow; e. The glass mercury thermometer used in the test is generally a fully immersed type, and it is not allowed to be removed from the measured medium when reading. f. Each set of temperature measuring devices should be in a normal working environment for at least two hours before the start of the test. 5.3 Flow measurement
5.3.1 Condensate flow measurement
Condensate flow can be measured by any of the following methods: a.
Weight measuring box (error within ±0.25%) b. Volume measuring box (error within ±0.5%); c. Venturi tube, nozzle, orifice plate and other standard throttling parts. This method should be measured in accordance with the provisions of GB2624. 5.3.2 Hot and medium water level
The water level change needs to be observed at the beginning and end of each test, and the condensate flow rate should be corrected according to the change of water level. 5.3.3 Density correction
The weight method is more reliable than the volumetric method. When the weight method is used for testing, the water density must be corrected when the water temperature changes. 5.3.4 Cooling water flow
The cooling water flow can be determined by one of the following methods: heat balance calculation method;
Salt cloud method +
Pitot tube measurement method:
calibrated (or standard) nozzle and orifice plate measurement method, ultrasonic flow meter method;
Turbine flow meter method.
5.3.5 Air volume extracted by steam ejector
Orifice plate (nozzle) and gas meter can be used to measure the air volume extracted from the condenser. The air volume should be measured on the exhaust side of the ejector. If it can be estimated, the steam content in the air should be corrected. If the air contains a large amount of water vapor, the mixture should be condensed through a cooler.
5.3.6 Cooling water leakage
The cooling water leakage in the condenser can be measured and calculated according to the P.Na method, or by draining the steam side of the condenser before the test, so that there is a certain pressure difference between the cooling water side and the steam side, and then measuring the cooling water leakage into the condenser heat exchanger. When the condenser is tested, the cooling water leakage is calculated based on the pressure difference between the steam and water sides. 5.4 In the measurement of pressure (or differential pressure), temperature, and flow, while ensuring a certain measurement accuracy, pressure (or differential pressure), temperature transmitters with data acquisition devices or other secondary instruments can also be used. 5.5 Time measurement
The timing method for the start and end of the test and the intermediate reading time is as follows: A signal clock or a timekeeper sends a signal on time: b. Timing according to each recorder's watch, but all these watches must be aligned uniformly before the test. When there is an integrator in the measuring device, the time measurement must be highly accurate. A stopwatch or electrical timing device with an error of less than 0.03% should be used. Special attention should be paid to the punctuality and synchronization of the readings of the timing device and the integrator. 8
5.6 Determination of oxygen content in condensate
JB/T3344-1993
The measurement of oxygen content in condensate must ensure the tightness of the vacuum system. Under this condition, dissolved oxygen meters, chemical analysis methods, etc. are used for measurement. 6 Determination of cleanliness factor
6.1 Purpose
When the condenser is in operation, the tubes will become dirty, and the heat transfer coefficient will decrease accordingly. In order to correctly identify the performance of the condenser, its cleanliness factor must be accurately determined.
6.2 Cleanliness factor
6.2.1 The cleanliness factor is a quantity used to characterize the degree of tube dirtiness. It is the ratio of the heat transfer efficiency of the old tube to that of the new tube under the same cooling water speed and temperature, alternating steam temperature and flow rate. The cleanliness coefficient of the entire condenser is the average of the cleanliness coefficients of all tubes. Usually, a certain number of representative tubes are selected for testing to determine the heat transfer coefficient of the entire condenser. 6.2.2 In the performance guarantee of the manufacturer, a reasonable range of the cleanliness coefficient of the condenser should be given. 6.2.3 For a dirty condenser, its heat transfer coefficient is equal to the product of the cleanliness coefficient and the heat transfer coefficient when all the tubes of the condenser are new tubes (the cleanliness coefficient is 1 at this time). However, this is approximate and must be corrected to the heat transfer coefficient under the design conditions. The manufacturer should provide a correction method that takes into account the effects of heat load, cooling water overflow and water velocity. 6.3 Instruments and devices required to measure the cleanliness coefficient of the sample tube 6.3.1 To measure the inlet and outlet water temperature of the sample tube, a secondary standard mercury thermometer with a 0.1C scale, or a thermocouple with considerable accuracy, a resistance thermometer or a temperature transmitter, and a precision bridge, or a galvanometer, or a data acquisition device are required. 6.3.2 Instruments and devices required for measuring the cooling water flow of the sample tube by the nozzle method: Standard pressure gauge: with an accuracy of 0.25, used to measure the cooling water pressure supplied to the isolated sample tube; b. Flow nozzle: The flow nozzle should be calibrated, and the error between the design value and the calibration value should not exceed 0.5%. The calibration range should be larger than the measurement range. The flow nozzle is installed on the side of the sample tube outlet to measure the flow of each individual sample tube. After the cooling water flows through the nozzle, the water can be directly released into the atmosphere.
water column observer or mercury pressure gauge (the meter reading should be accurate to 34Pa) is used to measure the pressure of the nozzle: d. A rubber hose with an inner diameter not less than the inner diameter of the cooling tube is passed through the chamber to connect the sample tube outlet and the nozzle. 6.3.3 Instruments required for measuring the cooling water flow of the sample tube by the salt cloud method: salt cloud instrument, nozzle, electrode, electric stopwatch and salt water injection device, etc. The test device at this time can be arranged according to the requirements of the "salt cloud method" measurement system. 6.3.4 Use a turbine flowmeter to measure the cooling water flow of the sample. 6.4 General requirements for testing
6.4.1 To determine the cleanliness factor, the data required for each sample tube include: the surface area of ​​the tube, the steam temperature of the weekly chart (take the condenser steam temperature), the inlet and outlet temperature and flow rate of the cooling water. To eliminate errors, these readings should be read at the same time as the overall test conditions. The corresponding cleanliness factor is calculated and sorted out from the records of each condition. During the test, even if the tube is not dirty, different water velocities will obtain different cleanliness factors (the change in the cleanliness factor is approximately inversely proportional to a certain power of the cooling water flow rate). 6.4.2 In order to improve the uniformity of the cleanliness of the entire condenser, all tubes of the condenser should be cleaned before the test. 6.4.3 Every four tubes form a group, which is called a test tube group. Each test tube group should be able to represent the average state in this area. And all test tube groups should be able to represent the average operating state of the entire condenser. The selection of test tube groups and the determination of the number of groups shall be jointly discussed and decided by all parties participating in the test. 6.4.4 The interval between each tube in the test tube group (daily tube) shall not exceed one tube. At least one group shall be selected for every 2000 tubes, and the whole condenser shall not be less than 4 groups. Only when the deviation between the average heat transfer coefficient of the test tube group and the heat transfer coefficient of the whole condenser is within the range of ±7%, it can be considered that the selection of the test tube group can represent the performance of the whole condenser. The steam filterability of the condenser shall be used as the standard for both calculations. 6.4.5 The tube at the center of each test tube group shall be removed and replaced with a new tube. The new tube shall meet the factory technical conditions, and its material and size shall be the same as the old one. It is best to use a well-protected tube left when installing the steam generator (leave 2). 6.4.6 The readings of the whole test should be taken at the same time. The time interval between readings is 2.5 minutes. The cleanliness factor of the condenser can be calculated according to Article 7.13.1.
6.5 Nozzle method measurement requirements
JB/T3344-1993
6.5.1 Supply of cooling water for sample tubes (new tubes and old tubes of the test tube group): The sample tubes are connected to the water chamber (front and rear water chambers) with rubber hoses (or insulating conduits) on the water side to achieve separate cooling water supply. The rubber hose and the cooling water of the condenser should be insulated to ensure that there is no heat exchange between the water flowing through the rubber hose and the cooling water in the water chamber (Figure 3). 1 New pipe replaced:
Thermometer
Pressure gauge
2--Test pipe group (old pipe)
Thermometer
Water column pressure gauge
Figure 3 Installation diagram of the test measuring device for the cleanliness coefficient of the condenser sample pipe 6.5.2 Each pipe (old pipe) of the test pipe group is connected to the cooling water at the inlet end with a hose or other conduit. The cooling water and the cooling water of the condenser have the same water temperature and water quality (preferably from the same water source). For a double-flow condenser, the outlet of the first-flow test pipe should be connected to the corresponding inlet of the second-flow test pipe. Measure the inlet water temperature in the water supply pipeline. When the water temperatures entering each test pipe group are different, each group should measure an inlet water temperature separately.
65.3 Except when the test is in progress, the cold water supply to the new pipe should be cut off (i.e., there is no water in the new pipe). During the preparatory test of the new pipe, if the measurement shows that the pipe is dirty, clean water, such as drinking water, must be supplied. The temperature of drinking water is usually lower than that of cooling water. In order to make its water temperature the same as that of the water supply to the old pipe, a small amount of steam can be passed into the water to heat it to achieve this purpose. 6.5. For the outlet of each sample pipe of a single-pass condenser, or the outlet of the sample pipe of the second pass of a double-pass condenser, a rubber hose should be used to
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