Patent · US Expired

Re-usable piston filter system

US5549816A · kind A · utility

30Cited by

16References

4Claims

0Family size

Assignee

Hach Company · US

Inventors

Daniel L. Harp · Loveland, US
Gary W. Johnson · Norwalk, US
Joe H. Myers · Pelham, US

Key dates

Filing date	Oct 31, 1995
Grant date	Aug 27, 1996
Priority date	—
Expiry date	Oct 31, 2015

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB01D33/0183
WIPO fieldChemical engineering
WIPO sectorChemistry

Abstract

A re-usable piston filter including an elongated tubular barrel member with a closed lower end and an open upper end, an elongated tubular piston member having an open upward end and a fluid-permeable lower end, and filter means detachably secured to the lower end of the piston. Downward movement of the piston in the barrel forces liquid in the barrel through the filter and into the tubular piston. An air valve in the barrel can be opened to enable the piston to be withdrawn from the barrel. The filter at the lower end of the piston can be changed or removed as desired.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.