Liquid circuit

Abstract

A liquid circuit for filtering a liquid, comprising a liquid storage vessel ( 10 ), a liquid pump ( 17 ), a consumer or user device ( 14 ), a filter element ( 23 ) and a controller ( 24 ). A heated liquid can be supplied at least partly to the filter element ( 23 ). The liquid circuit may be used in liquid systems in which a liquid, such as water, oil or fuel, is filtered and at least part of the liquid is returned to the storage vessel ( 10 ). The liquid is pumped in the liquid circuit from the storage vessel ( 10 ) by the pump ( 17 ) through lines ( 11, 13, 15, 16 ), filtered by filter element ( 23 ) and supplied to the consumer device ( 14 ). Excess liquid not required by the consumer device ( 14 ) is returned through liquid return line ( 15 ) to the controller ( 24 ) which directs the liquid either to the filter element ( 23 ) or the storage vessel ( 10 ), depending on the liquid temperature. The controller ( 24 ) and the filter element ( 23 ) are arranged in a common housing ( 18 ) having connectors for an unfiltered liquid inlet ( 19 ), a filtered liquid outlet ( 20 ), a liquid return ( 21 ) and a liquid outlet ( 22 ). The connectors ( 19, 20, 21 ) fixed to the housing enable rapid and simple assembly of the liquid circuit.

1 . A liquid circuit comprising a liquid storage vessel, a liquid pump, a consumer device, a filter element having an unfiltered liquid side and a filtered liquid side, and a controller with a temperature detection unit for determining the temperature of a liquid in the liquid circuit; said controller comprising a valve, responsive to the temperature of the liquid, for returning excess liquid not needed by the consumer device at least partially to the filter element; wherein said filter element and said controller are integrated into a common liquid filter system comprising a housing having an unfiltered liquid inlet communicating with the unfiltered liquid side of the filter element, a filtered liquid outlet communicating with the filtered liquid side of the filter element, a liquid return which communicates with the controller, and a liquid outlet which communicates with the controller; said liquid storage vessel being connected to the unfiltered liquid inlet by an unfiltered liquid line; said filtered liquid outlet being connected to the consumer device by a filtered liquid line; said consumer device being connected to the liquid return by a liquid return line, and said liquid outlet being connected to the storage vessel by a liquid drain line; wherein the controller is connected by a connection line to the unfiltered side of the filter element, and the temperature detection unit is arranged between the liquid storage vessel and the consumer device.  
   
   
       2 . A liquid circuit according to  claim 1 , wherein said liquid return line is a fuel return line of a fuel injection system.  
   
   
       3 . A liquid circuit according to  claim 1 , wherein the temperature detection unit is arranged on the unfiltered side of the filter element.  
   
   
       4 . A liquid circuit according to  claim 1 , wherein the temperature detection unit is arranged on the filtered side of the filter element.  
   
   
       5 . A liquid circuit according to  claim 1 , wherein the temperature detection unit is arranged on the liquid return line or on the liquid drain line.  
   
   
       6 . A liquid circuit according to  claim 1 , wherein said housing is constructed of a first, container part and a second, cover part, and said controller is positioned in the cover part, and said filter element is positioned in the container part.  
   
   
       7 . A liquid circuit according to  claim 1 , wherein the temperature detection unit is mechanically connected to the valve.  
   
   
       8 . A liquid circuit according to  claim 1 , further comprising a ventilation device positioned in the liquid filter system.  
   
   
       9 . A liquid circuit according to  claim 1 , further comprising means for withdrawing a second liquid separated from a first liquid in said filter system.  
   
   
       10 . A liquid circuit according to  claim 9 , wherein said first liquid is diesel fuel, said second liquid is water, and said means for withdrawing comprises a water discharge screw.  
   
   
       11 . A liquid circuit according to  claim 1 , further comprising a liquid heater integrated into the liquid filter system.  
   
   
       12 . A liquid circuit according to  claim 1 , further comprising a check valve arranged downstream from the controller.  
   
   
       13 . A liquid circuit according to  claim 1 , further comprising an overpressure valve for releasing excess liquid pressure from the filter system.  
   
   
       14 . A liquid circuit according to  claim 13 , wherein said overpressure valve is arranged downstream from the controller.  
   
   
       15 . A liquid circuit according to  claim 6 , wherein the cover part is attached to the container part in a liquid-tight manner with screws.  
   
   
       16 . A liquid circuit according to  claim 1 , wherein the liquid filter system is interposed in a fuel injection system of a diesel, internal combustion engine.