Face the radioactivity of stone products

Stone, the term has been associated with "radioactivity and radiation" in the previous period, and many consumers who want to use stone have been deterred by "stone radioactive". People who have used stone are still sitting on pins and needles and are often called. Where can I check the radioactivity of the stone? What if the home is covered with stone? The anxious meaning is overwhelming. What happens to the radioactivity of stone? Can I use it safely at home? In response to a series of questions, Associate Professor Hou Shengli of the Department of Applied Geophysics of China University of Geosciences answered the question. Only the stone that exceeds the standard is harmful. Prof. Hou analyzed that any substance in nature contains natural radioactive elements, but the content of radioactive elements in different substances is different. There are radioactive elements in the soil, water and even air in the surrounding environment. Non-stone building decoration materials such as cement, steel, bricks, and bricks all contain radioactive elements. Take bricks, which are made of clay and other materials. Clay is formed by the weathering of rocks. Clay and stone are all formed naturally. If the radioactive elements in clay are relatively high, then the whole body that has been fired The content of radioactive elements will also be correspondingly high, so it is incorrect to think that only the stone is radioactive and other materials are not radioactive. In the previous period, the Ministry of Public Health issued the “Standard for the Protection of Building Materials”, which imposes restrictions on the activity of natural radioactive elements in building materials to ensure safety in use. 80% of the stone can rest assured that in the indoor use which kind of stone is suitable for use in the home, how to choose the stone? Professor Hou said that as early as 1993, the National Building Material Bureau issued the "Classification Standards for Control of Radiological Protection of Natural Stone Products" to classify natural stone based on the level of radioactivity and classify natural stone into three categories: A, B, and C. Class A products can be used in any occasion. Class B products can be used in interior and exterior finishes and industrial facilities of buildings other than interior finishes. Class C standard stone can only be used as exterior finishes of buildings. From our test analysis of nearly 200 samples, 80% of the stone samples belong to Class A stone that can be used on any occasion. Among them, some of the stone's radioactive content is extremely low, even lower than the average cement floor, the brick's radioactive content, use this kind of stone in the room, can play a role in shielding, reduce the total indoor radiation, with environmental protection. Because some people lack the knowledge of radioactivity and formed some one-sided understanding, such as some people think that light-colored stone is less radioactive than dark stone, in fact, this is not absolute, and many dark-colored stones (such as red) have low levels of radioactivity. The standards set forth in Class A are lower than some light-colored stones, which can be demonstrated in the tests we have done. How to detect whether the indoor radioactivity exceeds the standard and how to detect whether the indoor material exceeds the standard is a concern for many people. According to Professor Hou, the conventional test methods are mainly indoor gamma spectrometry and radiochemical analysis. The samples to be tested are ground and sealed. The analysis cycle is about 20 days, and the long cycle analysis cost is also high. In view of this situation, under the support of the National Stone Quality Monitoring Center, the Department of Applied Geophysics of China University of Geosciences (Beijing) and the China Stone Industry Association jointly developed the first stone radioactive detector in China and related measurement methods and technologies. Certificate issued by Beijing Municipal Bureau of Quality and Technical Supervision. This kind of portable instrument can be brought to the scene for testing, without destroying the finished product, and can be directly tested on the finished product. The test range is up to 50×50 cm, and the detection time is short. Generally, it takes about 10 minutes to be measured. Finally, Professor Hou said that the home environment is a whole, as long as the radioactive index in this large environment reaches the standard, it will not affect the human body. Therefore, we must face up to the issue of “stone radiation” and do not blindly dismantle it because of concern about the excessive radioactivity of certain materials, causing unnecessary waste and trouble.
Don't forget to recommend this to friends posted on QQ/MSN (Jiangsu Construction Team, Xi'an 20 years experience in construction, consulting Q1057545818)

Cement decoration home

Chemical Industry Mass Flow Meter

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The meter can work with a pulse receiver(Count). The connection is as follows. The resistance value is up to the cable length & the max. input pulse frequency of receiver. Current 10mA is suitable for most receivers; however, you can reduce the resistance value when the cable is long. The max. current could be 50mA. Please use the fixed frequency output function to check if the cable length & resistance value is suitable.

Please check following items before operation, and operate according to relevant rules. a) If the meter is damaged during shipment and installation;
b) If the voltage is same as marked on nameplate;
c) If the fuse is correct;

d) If the meter is grounded properly.
e) If the Meter SN on the nameplate of sensor and transmitter are the same.
If everything is fine, please open all valves, make the pipeline full of liquid and then power on the meter for warm-up for 20min before operation. Finally, conduct zero calibration after first start, and shall do it again if the meter is moved to another site.
Preparation for zero calibration:
a) Power on the meter for approximately 20min for warm-up;
b) Run the process fluid through the sensor until the sensor temperature reaches the normal process operating temperature.
c) Close the shutoff valve downstream from the sensor.
d) Ensure that the sensor is filled with fluid and the process flow has completely stopped.


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