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Main Uses

This instrument is developed based on the National Building Materials Industry Standard of the People's Republic of China "Plaster Gypsum" (JC/T517-2004) for measuring the water retention rate of plaster gypsum. It can also be used for water retention tests of cement and mortar. A vacuum absorption experimental device is designed, and the water retention rate measured by this device is compared with the traditional filter paper method. Factors affecting the water retention rate of plaster gypsum and testing conditions are analyzed. Experiments show that measuring the water retention rate under negative pressure aligns with the actual wall substrate conditions and is reliable. The water retention rate measured under a certain pressure condition is comparable.

Main Technical Parameters

1. Vacuum negative pressure range: 0~110KPa.

2. Power supply voltage: 220V 50Hz.

3. Dimensions: 700×400×600 mm

4. Power: 200W

5. Net weight: 30Kg

Structural Features

The machine mainly consists of the air extraction part, experimental control part, and sample container part. The control system is convenient and flexible, easy to operate, with a reasonable overall layout and clear hierarchy, suitable for use by quality inspection departments at all levels and users.

Installation, Adjustment, and Experimental Operation Procedures

1. Installation and Debugging

When unpacking, check whether various glass containers are damaged and whether the vacuum pump lubricating oil reaches the horizontal line (the horizontal line near the vacuum pump glass window). Avoid loosening of all joints. Place the solid rubber stopper on the large suction filter bottle and open the air release valve.

2. Test Preparation

a. Check the air extraction system

Connect the power supply, open the air extraction valve, start the vacuum pump (do not remove your hand from the start switch). When the pressure reaches a negative pressure above 0.06KPa, turn off the vacuum pump. After one minute, check whether the instrument pressure decreases (it should decrease slowly, not rapidly). This checks whether the air extraction system is unobstructed and leak-free.

b. Install the cloth funnel

Remove the rubber stopper from the large suction filter bottle, install the cloth funnel with a rubber ring, and tighten the funnel to prepare for the experiment.

3. Experimental Steps:

A. Cut a piece of medium-speed qualitative filter paper according to the inner diameter of the cloth funnel and lay it at the bottom of the funnel. Wet the filter paper and the filter paper with water. Place the cloth funnel on the suction filter bottle, start the vacuum pump, filter for one minute, remove the cloth funnel, wipe off the residual water at the lower opening with filter paper, and weigh (G1) accurate to 0.1 grams.

B. Pour gypsum slurry with standard diffusion water amount into the weighed cloth funnel. Use a T-shaped scraper to vertically rotate and level the slurry in the funnel, keeping the slurry thickness within (10±0.5) mm. Wipe off residual gypsum slurry on the inner wall of the cloth funnel and weigh (G2) accurate to 0.1 grams. The time interval from mixing to weighing should not exceed 5 minutes.

C. Place the weighed cloth funnel on the suction filter bottle and start the vacuum pump. Adjust the negative pressure to (53.33±0.67) kPa within 30 seconds. Filter for 20 minutes, then remove the funnel, wipe off residual water at the lower opening with filter paper, and weigh (G3) accurate to 0.1 grams.

Calculate the water retention rate R of the gypsum slurry according to formula (1), accurate to 1%.

...........................................(1)

Where:

R........ Water retention rate of gypsum slurry, unit: percentage (%)

W1........ Equals (G2 - G1), the mass of gypsum slurry, unit: grams

W2........ Equals (G2 - G3), the mass of water lost from the gypsum slurry, unit: grams

G1........ Mass of cloth funnel and filter paper, unit: grams

G2........ Mass of cloth funnel with slurry, unit: grams

G3........ Mass of cloth funnel with slurry after filtration, unit: grams

K......... Standard diffusion water amount of gypsum slurry, unit: grams

If the difference between two consecutive water retention rate measurements and their average value is not greater than 3%, take the average as the test water retention rate; otherwise, the test should be redone.

Precautions

1. The vacuum negative pressure must not exceed the gauge range to avoid damaging the gauge.

2. Leakage caused by valve core loosening.

3. Regularly replace vacuum pump oil.

4. The vacuum pump oil level must not be below the observation window line; add oil in time. Replace the oil promptly if it changes color.

Company Profile

Hebei Yinfeng Experimental Instrument Co., Ltd. is a high-tech enterprise dedicated to the research and development, production, and sales of experimental instruments. The company is headquartered in Hebei Province, relying on the strong industrial foundation and technological innovation resources in the Beijing Tianjin Hebei region. It is committed to providing high-precision and high reliability testing equipment and solutions for material testing, engineering quality control, scientific research experiments and other fields.

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We provide customers with full-process services ranging from pre-sale consultation, customized solution design, equipment installation and commissioning to after-sale technical support.

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Gypsum Water Retention Rate Tester

This instrument is developed based on the National Building Materials Industry Standard of the People's Republic of China "Plaster Gypsum" (JC/T517-2004) for determining the water retention rate of plaster gypsum. It can also be used for testing the water retention rate of cement and mortar. A vacuum absorption experimental device was designed, and the water retention rate measured by this device was compared with the traditional filter paper method. Factors affecting the water retention rate of plaster gypsum and testing conditions were analyzed. Experiments show that measuring the water retention rate under negative pressure aligns with the actual wall substrate conditions and is reliable. The measured water retention rate is comparable only under certain pressure conditions.

Email:

info@cnhblabequipment.com

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+86-15931715356

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Main Uses

Main Technical Parameters

Structural Features

Installation, Adjustment, and Experimental Operation Procedures

Precautions

Gypsum Water Retention Rate Tester