The pipe cap (4) includes a column pipe cap body and a circular arc top cap (41) which are integratedly formed.

The amplification tube GroupWare’s are made up of tube cap and amplification tube.

At least one opening is set on the pipe cap (4).

A top pipe cap for a slag dropping pipe of a boiler fixedly mounted on the top end of the slag dropping pipe (5) comprises supporting componets, a connecting componet and a pipe cap (4).

The top pipe cap for slag dropping pipe of the boiler can slow down the falling speed of the slag.

The present invention also provides a wash-free PCR amplification tube used for direct gene detection, which includes a reaction tube, the tube is made up of tube cap and tube body.

A riser hat (50) is used to prevent a wash liquid from entering the riser and the liquid downcomer.

One end of each supporting feet is connected with the top pipe wall of the slag dropping pipe (5), the other end is connected with the pipe cap (4) by the connecting component.

The abrasion caused by the slag on the slag dropping pipe (5) and the pipe cap (4) can be reduced.

And the clogging of the slag dropping pipe by large size slag is also avoided.