GB/T 31427-2015Specification for determinator of coal ash fusibility (English PDF)

3.1 Type and structure of the determinator

The coal ash fusibility determinators include the testers that manually monitor and determine the shape change of the sample, and the testers equipped with an observation recorder that can automatically record the shape change of the sample. The performance shall comply with the relevant provisions of GB/T 219. heated according to the procedures specified in GB/T 30726: when the temperature is below 700 °C, the heating rate is 15 °C/min~20 °C/min; when the temperature is above 700 °C, the heating rate is 4 °C/min~6 °C/min.

3.5 Temperature controller

3.5.1 The temperature measurement range shall be 0 °C~1500 °C, and the resolution shall be 1 °C.

3.5.2 The temperature measurement error shall be not more than 5 °C.

3.5.3 The heating rate can be controlled according to 3.4.3

3.6 Observation recorder

3.6.1 The temperature change during the test and the shape change of the sample at the corresponding temperature can be recorded truthfully.

3.6.2 The test process with a real-time temperature display can be played back.

3.6.3 The test process can be monitored manually.

3.7 Appearance requirements

The metal coating and chemically treated surface shall be uniform in color; there shall be no exposed bottom, peeling, blistering, spots, scratches, or scuffing; it shall have good anticorrosion and anti-rust performance.

3.8 Insulation resistance and dielectric strength

The insulation resistance between the power terminal of the independent power supply part and the casing of the determinator shall not be less than 20 Mohm. It shall be able to withstand 1500 V, 50 Hz AC for 1 min, without arcing and breakdown.

4.1 High-temperature furnace

4.1.1 Determination of the maximum heating temperature: the high-temperature furnace shall be heated to the maximum temperature according to the heating program, which shall meet the requirements of 3.4.1.

4.1.2 Determination of the constant temperature zone: control the furnace temperature at 1000 °C, keep the temperature constant for 10 min, and use another set of standard platinum-rhodium platinum thermocouple pyrometers to determine the location and area of the constant temperature zone in the high-temperature furnace; the constant temperature zone shall meet the requirements of 3.4.2.

4.1.3 Determination of the heating rate: turn on the power of the high-temperature furnace, heat up to the maximum temperature according to the heating program, and record the temperature every 5 minutes through the temperature indicating instrument.

Calculate the heating rate before and after 900 °C or 700 °C, and the average heating rate within each 10 min shall meet the requirements of 3.4.3.

4.1.4 Inspection of the atmosphere: The atmosphere in the furnace shall be inspected according to the provisions of GB/T 219, which shall meet the requirements of 3.4.4.

4.1.5 Inspection of the observation port: Observe the shape change of the sample from the observation port by visual inspection, which shall meet the requirements of 3.4.6.

4.1.6 Determination of shell's temperature: Raise the temperature in the furnace to 1500 °C, and measure the temperature in the middle of the shell of the high-temperature furnace according to the provisions of GB 4793.1, which shall be meet the requirements of 3.4.7.

4.2 Temperature controller

4.2.1 Determination of the temperature control range and the heating rate: Measure it according to 4.1.1 and 4.1.3, and the results shall meet the requirements of 3.5.1 and 3.5.3.

4.2.2 Determination of the temperature measurement error: the high-temperature furnace shall be heated according to the heating program; when the temperature is at 700 °C, 800 °C, 900 °C, 1000 °C, 1100 °C, 1200 °C, 1300 °C, 1400 °C, and 1500 °C, use another set of standard platinum-rhodium platinum thermocouple pyrometers to determine the temperature in the furnace chamber of the high-temperature furnace, and the determined position shall be as close as possible to the thermocouple of the instrument. The difference between the displayed temperature value of the temperature controller and the measured temperature value shall meet the requirements of 3.5.2. the manufacturer according to the factory inspection items specified in Table 1. Only after being examined as qualified and getting a certificate can the determinator leave the factory.

5.3 Type inspection

5.3.1 Type inspection rules

Type inspection shall be carried out when one of the following situations happens:

a) Appraisement is carried out for the new product being put into production or the old product being transferred to another factory;

b) After the official production, there are major changes in the structure, material, and process, which may affect the performance of the product;

c) The production is resumed again after it has been stopped for more than 2 years;

d) Type inspection is carried out once every 2 years during the mass production;

e) There is a big difference between the factory inspection results and the last type inspection;

f) The national quality supervision agency puts forward the requirements for type inspection.

5.3.2 Sampling rules

According to GB/T 2828.1, sample from the finished products that have passed the factory inspection:

a) When the number of a batch does not exceed 25, take 2 samples;

b) When the number of a batch is 26~90, take 3 samples.

5.3.3 Judgment rules

According to the results of the sample inspection (the first sampling), if all the inspection items are qualified, the batch of products can be judged as qualified products.

When the number of a batch is not more than 25, if the number of unqualified products from the first sampling is greater than 0 and less than 2, 2 sets shall be randomly selected as the samples of the second sampling according to 5.3.2 for re-examination. If the total number of unqualified products from twice samplings is less than 2, the batch can be judged as qualified; otherwise, it is unqualified. When the number of a batch is 26~90, if the number of unqualified products from the first sampling is greater than 0 and less than 3, then select 3 more sets as the samples of the second sampling according to 5.3.2, and repeat the inspection. If the total number of unqualified products from twice […]