mechanical seal with low back pressure

例句：

1. 1. The mechanical seal in the pump is working perfectly.
   泵上的机械密封工作得非常好。
2. 2.The engineer designed a new type of mechanical seal to improve efficiency.
   工程师设计了一种新的机械密封，以提高效率。
3. 3. The manufacturer claims that their mechanical seal has a longer lifespan than other brands.
   制造商声称他们的机械密封比其他品牌有更长的使用寿命。