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US 5,334,309 AGranted
Filter units
AssigneePall Corporation
InventorsDavid J. Huggett, Jamie Collard
Life of this patent
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AssigneePall Corporation
InventorsDavid J. Huggett, Jamie Collard
Estimating the term…
A filter unit comprises a housing containing a filter element. The housing includes an inlet for fluid and an inlet passage which passes fluid to the filter element. An outlet passage conveys filtered fluid from the element to an outlet to the housing. The inlet passage includes a valve which can close the inlet passage. When this happens, a by-pass valve opens and connects the inlet to the housing direct to the housing outlet. An anti-backflow valve is provided in the outlet passage to prevent fluid passing back down the outlet passage to the filter element. The filter element can then be changed. A re-pressurization valve is provided to pass fluid to the element while the inlet passage is still closed and a vent port vents air from the element during this re-pressurization. Once re-pressurization is complete, the vent port and the re-pressurization valve are closed and the inlet valve opened so that filtration recommences.
A filter unit comprising a housing including a bowl, a filter element disposed in the bowl, means defining an inlet passage leading through the housing to the bowl for passage thereto of fluid to be filtered, means defining an outlet passage for filtered fluid leading through the housing from the bowl, an anti-backflow valve in the outlet passage, means defining a by-pass passage extending through the housing between a first point in the inlet passage and second point on the outlet passage on a downstream side of the anti-backflow valve, an inlet valve provided in the inlet passage between the first point and the filter element and operable to open or close the inlet passage, a by-pass valve which operates to open the by-pass passage when the inlet passage is closed for replacement of the filter element in the bowl and to close the by-pass passage when the inlet passage is open to re-direct fluid to the filter element, means defining a pressurization passage in the housing between the by-pass passage and a point on the inlet passage between the inlet valve and the bowl, and a repressurization valve provided in the housing and which is normally closed but operates to open the repressurization passage to pass fluid from the by-pass passage to the bowl with the inlet valve closed.
A filter unit comprising:
A filter unit comprising:
Dependencies are inferred from the claim text.