Fresh water marine flushing system and method

Abstract

A system and method for controllably connecting a marine vessel's native fresh water network to its raw water network in order to flush the raw water network. The controllable connection is provided by a hydrostatic lock—which ensures that water can only flow in the direction from the fresh water network to the raw water network and never in the opposite direction. A system controller directs the fresh water flush cycle and other operations.

Having described my invention, I claim: 
     
         1 . A system for selectively reducing the salinity of water contained within a raw water network of a vessel, comprising:
 (a) a raw water inlet in a hull of said vessel, said raw water inlet connected to said raw water network;   (b) an engine, having a raw water pump connected to said raw water network, said raw water pump having a raw water pump inlet and a raw water pump outlet;   (c) said raw water pump inlet applying suction to said raw water network in order to draw raw water in through said raw water inlet, through said raw water network, and into said raw water pump;   (d) said raw water pump pressurizing said raw water and propelling said raw water out said raw water pump outlet;   (e) a fresh water tank;   (f) a fresh water pump having an inlet connected to said fresh water tank and an outlet connected to a hydrostatic lock feed line;   (g) a raw water network connection connecting to a hydrostatic lock outlet line;   (h) a hydrostatic lock including,
 (i) a fresh water flush valve connected to said hydrostatic lock feed line, said fresh water flush valve being normally closed but being openable in response to an electrical signal, 
 (ii) a check valve located between said fresh water flush valve and said hydrostatic lock outlet line, said check valve allowing flow from said fresh water flush valve to said hydrostatic lock outlet line but preventing flow in an opposite direction; 
   (i) a swing gate valve in said raw water network and proximate said raw water inlet, said swing gate valve being configured to close when a first pressure within said raw water network exceeds a second pressure in said raw water inlet; and   (j) said fresh water pump delivering a pressure sufficient so that when said fresh water flush valve is open and said raw water pump is operating said first pressure within said raw water network is above said second pressure in said raw water inlet.   
     
     
         2 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 1 , further comprising:
 (a) a system controller, operable to selectively open said fresh water flush valve;   (b) a salinity sensor located in said raw water network; and   (c) said salinity sensor being connected to said system controller.   
     
     
         3 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 2 , further comprising said system controller being operable to energize said pump and hold said fresh water flush valve open until a salinity measured by said salinity sensor drops below a defined threshold. 
     
     
         4 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 1  wherein said fresh water tank is a native fresh water tank used as a source for a sink in said vessel. 
     
     
         5 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 1 , further comprising:
 (a) a second engine having a second raw water pump connected to said raw water network, said second raw water pump having a second raw water pump inlet and a second raw water pump outlet;   (b) said second raw water pump also applying suction to said raw water network; and   (c) said swing gate valve being located between said raw water pump and said raw water inlet.   
     
     
         6 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 5 , wherein said connection between said hydrostatic lock outlet line and said raw water network lies between said raw water pump and said second raw water pump. 
     
     
         7 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 5 , wherein said connection between said hydrostatic lock outlet line and said raw water network is a tee. 
     
     
         8 . A system for selectively reducing the salinity of water contained within a raw water network of a vessel, comprising:
 (a) a first engine having a first raw water pump;   (b) a second engine having a second raw water pump,   (c) a raw water inlet in a hull of said vessel;   (d) a raw water network connecting said raw water inlet to said first raw water pump and said second raw water pump;   (e) a fresh water tank;   (f) a fresh water pump having an inlet connected to said fresh water tank and an outlet connected to a fresh water flush valve, said fresh water flush valve being normally closed but being openable in response to an electrical signal;   (g) a raw water network connection between said fresh water flush valve and said raw water network;   (h) a swing gate valve in said raw water network, said swing gate valve being located between said first raw water pump and said raw water inlet, between said second raw water pump and said raw water inlet, and between said raw water network connection and said raw water inlet;   (i) said swing gate valve being configured to close when a first pressure within said raw water network exceeds a second pressure in said raw water inlet; and   (j) said fresh water pump delivering a pressure sufficient so that when said fresh water flush valve is open and said first and second raw water pumps are operating said first pressure within said raw water network is above said second pressure in said raw water inlet.   
     
     
         9 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 8 , further comprising:
 (a) a first heat exchanger receiving raw water from said first raw water pump; and   (b) a second heat exchanger receiving raw water from said second raw water pump.   
     
     
         10 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 9 , further comprising:
 (a) a first raw water exit downstream of said first heat exchanger;   (b) a second raw water exit downstream of said second heat exchanger;   (c) a first salinity sensor proximate said first raw water exit;   (d) a second salinity sensor proximate said second raw water exit; and   (e) a system controller monitoring said first and second salinity sensors, said system controller being operable to selectively open said fresh water flush valve.   
     
     
         11 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 10 , said system controller being configured to hold open said fresh water flush valve until a first salinity measured by said first salinity sensor and a second salinity measured by said second salinity sensor both fall below a defined threshold. 
     
     
         12 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 11 , said system controller being configured to energize said fresh water pump until said first salinity and said second salinity fall below said threshold. 
     
     
         13 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 8 , further comprising a check valve located between said fresh water flush valve and said connection between said fresh water flush valve and said raw water network, said check valve said check valve allowing flow from said fresh water flush valve to said raw water network but preventing flow in an opposite direction. 
     
     
         14 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 8 , wherein said swing gate valve includes a reverse flow aperture permitting a small reverse flow even when said swing gate valve is closed. 
     
     
         15 . A system for flushing raw water contained within a raw water network of a vessel with fresh water, comprising:
 (a) a raw water inlet in a hull of said vessel, said raw water inlet connected to said raw water network;   (b) an engine, having a raw water pump connected to said raw water network, said raw water pump having a raw water pump inlet and a raw water pump outlet;   (c) said raw water pump inlet applying suction to said raw water network in order to draw raw water in through said raw water inlet, through said raw water network, and into said raw water pump;   (d) said raw water pump pressurizing said raw water and propelling said raw water out said raw water pump outlet;   (e) a fresh water tank;   (f) a fresh water pump having an inlet connected to said fresh water tank and an outlet connected to a fresh water flush valve;   (g) said fresh water flush valve selectively connecting said fresh water pump outlet to a raw water network connection;   (h) said fresh water flush valve being normally closed but being openable in response to an electrical signal;   (i) a swing gate valve in said raw water network and proximate said raw water inlet, said swing gate valve being configured to close when a first pressure within said raw water network exceeds a second pressure in said raw water inlet; and   (j) said fresh water pump delivering a pressure sufficient so that when said fresh water flush valve is open and said raw water pump is operating said first pressure within said raw water network is above said second pressure in said raw water inlet.   
     
     
         16 . The system for flushing raw water contained within a raw water network of a vessel as recited in  claim 15 , further comprising:
 (a) a first heat exchanger receiving raw water from said first raw water pump; and   (b) a second heat exchanger receiving raw water from said second raw water pump.   
     
     
         17 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 16 , further comprising:
 (a) a first raw water exit downstream of said first heat exchanger;   (b) a second raw water exit downstream of said second heat exchanger;   (c) a first salinity sensor proximate said first raw water exit;   (d) a second salinity sensor proximate said second raw water exit; and   (e) a system controller monitoring said first and second salinity sensors, said system controller being operable to selectively open said fresh water flush valve.   
     
     
         18 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 17 , said system controller being configured to hold open said fresh water flush valve until a first salinity measured by said first salinity sensor and a second salinity measured by said second salinity sensor both fall below a defined threshold. 
     
     
         19 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 18 , said system controller being configured to energize said fresh water pump until said first salinity and said second salinity fall below said threshold. 
     
     
         20 . The system for selectively reducing the salinity of water contained within a raw water network of a vessel as recited in  claim 15 , further comprising a check valve located between said fresh water flush valve and said connection between said fresh water flush valve and said raw water network, said check valve said check valve allowing flow from said fresh water flush valve to said raw water network but preventing flow in an opposite direction.