Liquid filter system

A liquid filter system for use with a waste water treatment plant comprising two filters, each filter having a housing, a filter screen mounted in the housing to provide a space between the filter and the housing, an inlet in one end of the housing through which water enters the screen and is filtered through the walls of the screen into the annular space, a filtered water outlet in the housing, a second outlet in the other end of the housing through which unfiltered water flows out of the housing, a flow line connecting the filtered water outlets of both filters together and to a common filtered water line, a pressure regulator in the common filtered water flow line to limit the pressure of the filtered water provided by the system, and a restriction in the second outlet in the housing of the first filter to restrict the flow of unfiltered water from the first filter to maintain the pressure of the filtered water sufficient for a portion of the filtered water to flow into the annular space between the filter screen and the housing of the second filter to backwash the filter screen in the second filter, and means for alternating the flow of water to the filters to alternately backwash each filter as the other is filtering the waste water.

In a sewage treatment system including a septic tank for receiving the sewage initially and through bacterial action reducing the BOD of the effluent as it leaves the tank, the improvement comprising a filter system downstream of the tank through which the effluent flows to filter a sufficient amount of solids out of the effluent to reduce the BOD of the effluent, the filter system comprising two filters, each having a housing and a filter medium located in the housing through which the effluent flows in one direction to be filtered before entering the irrigation system, a distributing valve assembly for alternating the flow of effluent from one to the other of the filters, an effluent discharge line connected to each filter to carry filtered effluent to a line connected to the irrigation system, a pressure regulator in the line to the irrigation system to create a back pressure in the line from the filters to cause a portion of the effluent from the filtering filter to flow through the filter medium of the non-filtering filter and backwash the non-filtering filter.

A filter system for use with a waste water treatment plant to reduce the solids in and the BOD of the effluent from the plant comprising two filters, each filter having a housing, a filter screen mounted in the housing to provide a space between the filter and the housing, an inlet in one end of the housing through which water enters the screen and is filtered through the walls of the screen into the annular space, a filtered water outlet in the housing, a second outlet in the other end of the housing through which unfiltered water flows out of the housing, a flow line connecting the filtered water outlets of both filters together and to a common filtered water line, a pressure regulator in the common filtered water flow line to limit the pressure of the filtered water provided by the system, and a restriction in the second outlet in the housing of the first filter to restrict the flow of unfiltered water from the first filter to maintain the pressure of the filtered water sufficient for a portion of the filtered water to flow into the annular space between the filter screen and the housing of the second filter to backwash the filter screen in the second filter, and means for alternating the flow of water to the filters to alternately backwash each filter as the other is filtering the waste water to reduce the solids in and the BOD of the effluent.

In a sewage treatment system including a septic tank for receiving the sewage initially and through bacterial action reducing the BOD of the effluent as it leaves the tank, the improvement comprising a filter system downstream of the tank through which the effluent flows to filter a sufficient amount of solids out of the effluent to reduce the BOD of the effluent, the filter system comprising two filter assemblies, each having a housing and a filter medium located in the housing through which the effluent flows in one direction to be filtered, a distributing valve assembly for alternating the flow of effluent from one to the other of the filter assemblies, an effluent discharge line connected to each filter assembly, a pressure regulator in the line to the irrigation system to create a back pressure in the effluent discharge line from the filters to cause a portion of the effluent from the filtering filter to flow through the filter medium of the non-filtering filter and backwash the non-filtering filter.