The Emergency Sensor Light is specially designed for ceiling Mounted emergency lighting and with Microwave Sensor. from 12inch 18W to 18inch 36W. Dimmable lighting, Waterproof and Dustproof avialable. Widely using for Office and Household. Automatically light at once when buildings main power outage. It is more than 3 hours emergency time. When Main power is on, it use as an normal sensor lighting Led Emergency Sensor Light,Emergency Light Sensor,Microwave Sensor Emergency Light,Emergency Sensor Light Foshan Nai An Lighting Electric Co.,ltd , https://www.twinspotlights.com
Leakage of the valve there are two main reasons, one is the internal leakage; the second is leakage. The main reason that the valve produces internal leakage is that the seal pair is deformed at a low temperature. When the media temperature drops to make the material phase change caused by the volume change, the original grinding precision of the sealing surface warpage caused by low temperature sealing bad. We have DN250 valve low temperature test, the medium is liquid nitrogen (-196 ℃) Butterfly material 1Cr18Ni9Ti (no low temperature treatment) found that the sealing surface warpage deformation of about 0.12mm, which is the main cause of internal leakage. Newly developed butterfly valve from the plane seal to cone seal. The valve seat is an oblique cone oval sealing surface, and the butterfly valve is mounted on the circular seal ring is composed of flexible seal. Seal ring can float radially within the disc groove. When the valve is closed, the elastomeric seal first comes into contact with the minor axis of the elliptical sealing surface. As the valve stem rotates, the sealing ring is pushed inwardly forcing the elastomeric ring into contact with the longer axis of the bevel, eventually causing the elastomeric sealing ring All contact with the elliptical sealing surface. Its sealing is achieved by the elastic ring deformation. Therefore, when the valve body or disc deformation occurs at low temperature, it will be compensated by the elastic sealing ring without leakage and jamming. When the valve is opened, the elastic deformation immediately disappears, basically no relative friction in the opening and closing process, so long service life. Valve leakage causes: First, the valve and the pipe flange connection, due to the connection padding, connecting bolts, and connectors at low temperature shrinkage between the material is not synchronized with the resulting slack and lead to leakage. Therefore, we change the way of connecting the valve body and the pipeline from the flange connection to the welding structure, so as to avoid the low-temperature leakage. The second is the stem and packing leaks. Most of the general valve filling F4, because of its good self-lubricating properties, small friction coefficient (friction coefficient of steel f = 0.05 ~ 0.1), but also has unique chemical stability, it has been widely used. However, F4 also has shortcomings, first, cold tendency; Second, the linear expansion coefficient, resulting in shrinkage at low temperatures lead to leakage, resulting in a lot of ice at the valve stem, so that the valve open failure. Developed for this reason, the use of self-shrinking seal structure of low-temperature butterfly valve that is the use of large expansion coefficient F4 features, through the gap to reach the room temperature, low temperature can be sealed.