This kind of valve's working pressure is not bigger than 0.7 megabar generally, the nominal size is not bigger than 300 millimeters. 这种阀的工作压力一般不大于0.7兆帕,公称通径不大于300毫米。
The bar is a metric unit of pressure, but not part of the International System of Units (SI). It is exactly equal to 7005100000000000000♠100000Pa and is slightly less than the average atmospheric pressure on Earth at sea level.
The bar and the millibar were introduced by the British meteorologist William Napier Shaw in 1909, while he was the director of the Meteorological Office in London.