Medical merchandising enterprises, as a important section of medical industry, connect two links of production and consumption, and play the indispensable role in medical circulation market.
When operated, the circulation sub allows a higher circulation rate to be established by opening a path to the annulus in the top section of the tool string.
循环接头在工作时在工具管柱的上段打开通向环形空间的通路，于是能够建立较大的循环流量。
3
Water level difference crossing Lianhuatang section reduced by circulation flow is one of the most important problem in flood control.