| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piston pump for a low temperature liquid, which is designed for a high working pressure. <P>SOLUTION: A pump piston having a truncated conical piston top end is used. A valve head has an exit opening and a cavity corresponding to the piston top end. A discharge valve is arranged adjoining to the exit opening and intruding into a cylinder head. The piston top end is configured to penetrate the cavity region when the piston pump stroke is at the maximum. Since the piston top end is shaped to tightly fit the cavity of the valve head and completely intrudes the cavity region at the maximum piston stroke, a low temperature medium is always mechanically and completely eliminated from the valve head in each piston pump stroke. Further, since the discharge valve is arranged directly adjoining to the exit opening of the valve head and intruding into a sealed pressure pipe, no cavity is left in the pump working chamber where the low temperature medium can remain, and thereby, functional disorders due to a residual medium can be significantly decreased. <P>COPYRIGHT: (C)2012,JPO&INPIT |
