groove for grooved-hole joints是什么意思

用法例句

It also introduced the calculating method of expansion slot abd the instructions of how to use it.

介绍了载热体系统循环泵流量、扬程、净吸压力的计算方法及循环泵的类型;介绍了膨胀槽容量的计算方法及膨胀槽的使用方法。