JG/T 246-2009Apparatus to determine air content of fresh concrete (English PDF)

3.1 Classification

According to direct display is divided into.

a) pointer type, code-named Z;

b) the number of explicit, code-named S.

3.2 Mark

3.2.1 Marking methods

The marking of the gas meter consists of the gas meter code, the direct reading display code and the three parts of this standard, as follows.

3.2.2 Example of marking

a) The indicator gas meter is expressed as.

HQZ JG/T 246-2009;

b) The digital gas meter is expressed as.

HQS JG/T 246-2009.

4.1 Composition

Gas meter mainly by the container and the cover of two parts, as shown in Figure 1.

1 - gas content - pressure gauge;

2 --- operating valve;

3 --- exhaust valve;

4 - fixed clip;

5 --- cover;

6 --- container;

7 --- inlet valve;

8 --- intake valve;

9 --- air chamber;

10 --- take water pipe;

11 --- calibration tube.

a) the use of inflatable cylinder pressure meter 1 - gas content - pressure gauge;

2 --- operating valve;

3 --- exhaust valve;

4 - fixed clip;

5 --- cover;

6 --- container;

7 --- inlet valve;

8 --- hand pump;

9 --- air chamber;

10 --- take water pipe;

11 --- calibration tube;

12 - air chamber exhaust valve.

b) the use of hand pump pressure meter

Figure 1 gas meter structure diagram

The use of inflatable pump pressure meter, cover part of the main by the inlet valve, intake valve, air chamber, operating valve, exhaust valve and gas - pressure

Table or digital display system, etc. The use of hand pump pressure meter, the lid part of the main by the inlet valve, hand pump, air chamber, air chamber exhaust

Valves, operating valves, exhaust valves and gas content - pressure gauge or digital display system, etc. Water pipes and calibration tubes are used at the timing of the instrument.

4.2 Conditions of use

The gas meter should be used and verified at a temperature of 20 ° C ± 10 ° C. When the ambient temperature is outside this range, the gas meter should be re-set before use. Digital display gas meter should be equipped with automatic temperature correction system.

The new purchase of gas meter, the instrument should first be calibrated rate, its gas - pressure gauge or digital display of gas content should be with the container the amount of air contained in the percentage of the equivalent, otherwise it should be adjusted for the use of gas meter, according to the use of the rate of determination, the longest Once a year, and the original rate of the difference between the value should be less than equal to 0.2%, when the error exceeds this value should be adjusted or repaired.

4.3 Materials

The gas containing container and the lid shall be made of hard metal which is corrosion resistant to the slurry and shall be of the same material as the container.

5.1 Containers and covers

The diameter and depth of the container shall be equal to the volume of 7000 mL ± 25 mL. The container mouth and the part of the lid and the container shall be connected the surface of the container, the surface of the container connected to the lid and the inner surface of the lid body shall be machined as smooth surface, and the surface roughness is not should be lower than R a 1.6.

5.2 Gas content

Between the container and the lid can be bolts, buckles or other means of connection, and should be equipped with a ring to ensure that after assembly in the 0.1MPa ~ 0.2MPa pressure with good watertightness and air tightness, and under this pressure volume change rate should not exceed 0.1%.

Gas content - pressure gauge or digital display should be able to directly read or show the gas content value, the pressure measurement range should be 0MPa ~ 0.25MPa, Gas content range should be 0 ~ 8%. Gas content range of 0 ~ 3%, the division value should be less than or equal to 0.1%; gas content range of 3% to 6% , The scale value should be less than or equal to 0.2%; gas content range of 6% to 8%, the division value should be less than or equal to 0.5%.

The degree should also meet the requirements specified in GB/T 1227.

5.3 The parts should be complete, normal and non-destructive. The outer surface should be smooth and smooth, the inner surface should be smooth, no rugged, and should not be painted.

6.1 Containers and covers

6.1.1 Determination of container volume

At room temperature 20 °C ± 2 °C conditions, using a 300mm × 300mm organic flat glass; platform scales, weighing 50kg, the amount of Less than 5g; measuring a cylinder, the capacity of 100mL for the determination of dry containers and flat glass, the total weight of W1, accurate to 5g, add water to the container Close to the upper edge, and then add the water level flat flat glass until the container mouth to cover, and make the plate under the glass plate does not clip any bubbles.

(W2-W1) is the quality of the water in the container, divided by the difference between the two weighing weights (W2-W1) the density of the water at this temperature (the density of water intake is 1.0g/mL) is the volume of the container, which should meet the requirements of 5.1.

6.1.2 Surface roughness is measured using a surface roughness meter.

6.2 Gas content

6.2.1 Test of air tightness, watertightness and volume change rate

a) Fill the container with water, insert the rubber seal, seal and tighten the retaining clip.

b) Open the intake valve with the gas-filled gas meter pressurized, close the remaining valves; use the hand pump to pressurize the gas meter to close all the valve is pressurized with a pump from the intake valve or hand pump so that the pressure is slightly greater than 0.1 (or 0.2) MPa and then fine-tuned to 0.1 (Or 0.2) MPa. For 10min, if the pressure gauge reading or digital display value is stable, indicating good air tightness.

As the valve, continue to maintain 10min, observe whether there is gas, water leakage, and pressure gauge reading or digital display is stable.

Note. For the gas with the pump pressure meter, with the intake valve to fine-tune the pressure value; for the hand pump pressure meter, with the air chamber exhaust valve fine-tuning pressure value.

The same as below.

6.2.2 Visual gas content - pressure gauge or digital display pressure range, gas content range and scale value is consistent with the requirements of 5.2.

6.2.3 Determination of gas content indication error

a) Fill the container with water, insert the water inlet valve into the water pipe, and place the cover on the container and tighten the retaining clip.

b) Close the operating valve, open the inlet and exhaust valves, add water from the inlet valve with a water injector, and shake the gas meter (slightly tilted, Valve lift), exhaust from the exhaust valve until the exhaust valve outlet water continuously so far, close the inlet valve and exhaust valve.

The pumped gas meter also closes the chamber exhaust valve.

c) Press the pump with the pump from the intake valve or the hand pump to pressurize the initial pressure line (0.1MPa or 0.2MPa). After stopping for 5s, Micro-open air intake valve or air chamber exhaust valve, so that the gauge or digital display accurately positioned on the initial pressure line. Micro-operation valve, if the point Zero, that is, the instrument zero calibration qualified.

Note. When the pointer or display does not point to zero, you should first check whether the gas inside the container is drained or the cover is tightened.

d) After zero calibration, connect a calibration tube to the upper end of the inlet valve, through the calibration tube and water intake pipe from the container to the cylinder, the suction Into the container 1.0% (actually more than 1.0%). Close the inlet valve.

e) open the exhaust valve, so that the pressure inside the container and atmospheric pressure balance; open the inlet valve, the cylinder more than 1.0% part of the suction tube and then through the inlet valve to return to the container. Close the inlet and exhaust valves. Press again to make the chamber pressure slightly pressure.

f) fine-tune the intake valve or air chamber exhaust valve to the needle or digital display for the initial pressure value, stop for 5s, micro-operation valve to be pointer or number the code shows a stable reading and the reading should be 1.0%.

g) Repeat the above steps, taking 2.0%, 3.0%, 4.0%, 8.0% of the water, the reading should be 2.0%, 3.0% 4.0%, 8.0%.

h) observe the percentage of container aspirated water and the gas content - whether the error in the pressure gauge or digital display reading exceeds 5.2 Value requirement.

6.3 visual inspection using visual inspection.

7.1 Inspection Classification

Gas meter test is divided into type inspection and factory inspection.

7.1.1 Type inspection

Where any of the following circumstances, should be type test.

a) new products or old products to the factory production of stereotypes identification;

b) changes in structure, process or material to affect product performance;

c) at least once a year for normal production;

d) discontinued for more than six months (including six months) to resume production;

e) the factory inspection results and the last type of inspection are quite different;

f) When a national quality supervision agency proposes a type inspection request.

7.1.2 Factory inspection

The type of qualified, formally put into operation of the gas meter, should be in the factory by the factory quality inspection department according to the factory inspection project test.

7.2 Test items

All kinds of gas measuring instruments shall meet the requirements of Table 1.

Table 1 Test items

No. Test item category Inspection by inspection category Requires test method type inspection factory inspection 1 container and cover in general 5.1 6.1 sqrt sqrt

2 Closed Main 5.2 6.2 sqrt sqrt 3 air content indication error main 5.2 6.2 sqrt sqrt

4 Appearance General 5.3 6.3 sqrt sqrt

7.3 Determination of rules

7.3.1 Type inspection

Each model containing gas meter randomly selected 2, according to Table 1 in the type of inspection items for testing, the main project should all meet the standards in the general project, when the number of substandard items exceeds one item, the type test is not passed; when only one item can not meet the requirement, Permitting double sampling of unqualified items. After re-examination, when all meet the requirements, can be judged as qualified; when there is still one does not meet the standard when the request is made, it is judged as unqualified.

7.3.2 Factory inspection

Where the factory of each gas meter, according to the test items specified in Table 1 for inspection, all qualified, the prospective factory. Factory inspection of the main the measured data of the project should be included in the random file.

8.1 Mark

Each gas meter should be fixed in the appropriate location of product signs.

The label includes. product name, mark, nominal capacity, manufacturer name, factory number and date of manufacture.

8.2 Packaging

The gas meter is sealed and sealed in a sealed plastic bag and is marked with the words "rain and snow" and "carefully".

Should be placed in the toolbox random factory.

Each gas meter should be shipped with factory product manual, product certification, report and packing list.

8.3 Transport

Products in the transport process, should avoid collision, throwing and rain and snow.

8.4 Storage

The gas meter should be protected from moisture and should be stored in a clean and well-ventilated warehouse.