PLATE HEAT EXCHANGER WITH AUXILIARY FLUID CBRCUIT

TECHNICAL FIELD

[0001] The present invention relates to heat exchangers and more specifically concerns a plate heat exchanger comprising a plurality of heat exchange plates including various fluid supply channels and discharge channels arranged through the plurality of heat exchange plates. At least one conduit heat exchanger is connected to extend at least partially through one or more of the fluid discharge channels or the supply channels.

BACKGROUND [0002] Typical plate heat exchangers may accommodate a first fluid acting as a cooling media and multiple second fluids acting as a hot media. Plate heat exchangers are commonly used to cool machinery lubricating oil, engine jacket cooling water, and other fluids. Currently, in order to add an additional fluid circuit to an existing plate heat exchanger, one must add a series of blocking plates and appropriately configured heat exchange plates to the existing plate heat exchanger unit, adding both space and weight to the unit. This can be detrimental to engine mounted units, and may be cost prohibitive. There exists a need to add a fluid circuit to a plate heat exchanger without reconfiguring the plate package or significantly adding to the size or weight of the plate heat exchanger.

PRIOR ART

[0003] WO 2005/054758 Al discloses a heat exchange device including a plate heat exchanger, wherein the plate heat exchanger includes a plate package of heat transfer plates, which are arranged to form between the plates first passages for a heat transfer medium to be cooled and second passages for a cooling agent. The heat exchanger device includes a fixed conduit extending into an inlet channel for the cooling agent. The conduit forms part of the evaporator circuit of a refrigeration system.

SUMMARY

[0004] A plate heat exchanger is provided having an auxiliary fluid circuit. The auxiliary fluid circuit is particularly suitable for after cooling or pre-heating fluids used in a machinery arrangement. A plate heat exchanger of the type typically known in the art has a first fluid (cooling media) supply channel and a first fluid discharge channel running through the heat plate package. The plate heat exchanger also has at least one second fluid (hot media) supply channel and at least one second fluid discharge channel running through the heat plate package. The invention further comprises the addition of one or more auxiliary fluid heat exchange circuits including a conduit heat exchanger adapted to fit inside either the first fluid supply or discharge channels when acting as an after cooler, or the second fluid supply or discharge channel when acting as a pre-heater.

[0005] In some implementations a plate heat exchanger is provided comprising a plurality of heat exchange plates including two end plates; a first liquid supply port through one of the end plates and in communication with a first liquid supply channel through the plurality of heat exchange plates; a first liquid discharge port connected through one of the end plates and in communication with a first liquid discharge channel through the plurality of plates; at least one second liquid supply port connected through one of the end plates and in communication with a second liquid supply channel through the plurality of plates; at least one second liquid discharge port connected through one of the end plates and in communication with a second liquid discharge channel through the plurality of plates; and a conduit heat exchanger fixedly connected to one of the end plates and in communication with either the first fluid supply channel, the first fluid discharge channel, the second fluid supply channel, or the second fluid discharge channel, the conduit heat exchanger further comprising. The conduit heat exchanger can comprise a conduit having a supply and return; a flange for fixedly connecting to a port on the end plate; a supply connection extending outwardly from the flange and in communication through the flange with the supply of the conduit; and a return connection extending outwardly from the flange and in communication through the flange with the return of the conduit.

[0006] In another implementation the plate heat exchanger can comprise a conduit that extends from a flange connection into a first liquid discharge channel, a first liquid supply channel, a second liquid discharge channel, or a second liquid supply channel.

[0007] In a further implementation the conduit heat exchanger cools a fluid flowing through the conduit. In yet another implementation the conduit heat exchanger warms a fluid flowing through the conduit.

[0008] In some implementations the plate heat exchanger further comprises a pipe connected to either a first liquid discharge port, a first liquid supply port, a second liquid discharge port, or a second liquid supply port, wherein a conduit heat exchanger is connected to the pipe. In other implementation the plate heat exchanger further comprises a strainer connected to the pipe, wherein the conduit heat exchanger is connected to the strainer. The conduit can extend through the pipe but not into either the first liquid discharge channel, the first liquid supply channel, the second liquid discharge channel, or the second liquid supply channel.

[0009] In another implementation a plate heat exchanger is provided comprising a plurality of heat exchange plates including two end plates; a first liquid supply port through one of the end plates and in communication with a first liquid supply channel through the plurality of heat exchange plates; a first liquid discharge port connected through one of the end plates and in communication with a first liquid discharge channel through the plurality of plates; at least one second liquid supply port connected through one of the end plates and in communication with a second liquid supply channel through the plurality of plates; at least one second liquid discharge port connected through one of the end plates and in communication with a second liquid discharge channel through the plurality of plates; an end plate port through one of the end plates, the end plate port being in communication with either the first liquid discharge channel, the first liquid supply channel, the second liquid discharge channel, or the second liquid supply channel; and a conduit heat exchanger fixedly connected to the end plate port. The conduit heat exchanger further can further comprise a conduit having a supply and return; a flange for fixedly connecting to a

port on the end plate; a supply connection extending outwardly from the flange and in communication through the flange with the supply of the conduit; and a return connection extending outwardly from the flange and in communication through the flange with the return of the conduit.

[0010] hi some implementations the conduit heat exchanger further comprises a sacrificial anode. The conduit and flange can include titanium, copper-nickel alloy, stainless steel, bronze, or alloy C-276.

[0011] m other implementation a fluid flows through the conduit, the fluid servicing a ship's propulsion equipment, maneuvering equipment or auxiliary equipment. The fluid can comprise diesel oil, fuel oil, machinery lubrication oil, hydraulic fluid, oil purification supply or return oil, fresh water, sea water, black water, grey water, potable water, or waste water.

[0012] In still another implementation a plate heat exchanger is provided comprising a plurality of heat exchange plates including two end plates; a first liquid supply port through one of the end plates and in communication with a first liquid supply channel through the plurality of heat exchange plates; a first liquid discharge port connected through one of the end plates and in communication with a first liquid discharge channel through the plurality of plates; a second liquid supply port connected through one of the end plates and in communication with a second liquid supply channel through the plurality of plates; at second liquid discharge port connected through one of the end plates and in communication with a second liquid discharge channel through the plurality of plates; a third liquid supply port connected through one of the end plates and in communication with a third liquid supply channel through the plurality of plates; at third liquid discharge port connected through one of the end plates and in communication with a third liquid discharge channel through the plurality of plates; an end plate port through one of the end plates, the end plate port being in communication with either the first liquid discharge channel, the first liquid supply channel, the second liquid discharge channel, the second liquid supply channel; the third liquid discharge channel or the third liquid supply channel; and a conduit heat exchanger fixedly connected to the end plate port. The conduit heat

exchanger can further comprise a conduit having a supply and return; a flange for fixedly connecting to a port on the end plate; a supply connection extending outwardly from the flange and in communication through the flange with the supply of the conduit; and a return connection extending outwardly from the flange and in communication through the flange with the return of the conduit.

[0013] In another implementation the conduit extends from a flange into any of a first liquid discharge channel, a first liquid supply channel, a second liquid discharge channel, a second liquid supply channel, a third liquid discharge channel, or a third liquid supply channel.

[0014] In some implementations the plate heat exchanger can include two or more conduit heat exchangers. At least one of the two or more conduit heat exchangers can cool a fluid. At least one of the two or more conduit heat exchangers can warm a fluid.

[0015] Plate heat exchangers having a conduit heat exchanger servicing an auxiliary fluid, circuit, as further disclosed below, provide for cost, space and weight savings over current solutions for adding a fluid circuit to a plate heat exchanger. The plate heat exchanger contemplated herein presents advantages over the prior art by utilizing the previously unused space in either the first fluid flow channels or the second fluid flow channels, similar to placing a shell-and-tube heat exchanger within the fluid flow channels of a traditional plate-type heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 discloses a schematic exploded view of an embodiment of a plate heat exchanger device according to the invention.

[0017] FIG. 2 discloses a side view of an embodiment of a conduit heat exchanger of the plate heat exchanger device according to the invention.

[0018] FIG. 3 discloses a side view of an embodiment of a conduit portion of the heat exchanger device according to the invention.

[0019] FIG. 4 discloses a side view of another embodiment of a conduit portion of the heat exchanger device according to the invention.

[0020] FIG. 5 discloses a top view of an embodiment of a plate heat exchanger device according to the invention.

[0021] FIG. 6 discloses a schematic exploded view of an embodiment of a multicircuit plate heat exchanger device according to the invention.

[0022] FIG. 7 discloses a top view of an embodiment of a multi-circuit plate heat exchanger of the device according to the invention.

[0023] FIG. 8 discloses a schematic exploded view of another embodiment of a plate heat exchanger device according to the invention.

[0024] FIG. 9 discloses a schematic exploded view of an after-cooler embodiment of a plate heat exchanger device according to the invention.

[0025] FIG. 10 discloses a schematic exploded view of a pre-cooler embodiment of a plate heat exchanger device according to the invention.

DETAILED DESCRIPTION

[0026] Plate heat exchangers are commonly used as lubricating-oil coolers and engine jacket water coolers, though they may also commonly be used to cool a variety of other fluids. As shown in Fig. 1, a plate heat exchanger 10 consists of the front end plate 13, the heat transfer plates 12 forming heat plate package 11, the back end plate 14, one or more tie bolts 15, and the carrier rail 16. The inlet and the outlet for the cooling fluid, such as seawater or cooling tower water, and the heat exchange medium, such as lubricating oil or engine jacket water, may be on the same end plate of the plate heat exchanger, for example, front end plate 13. Alternatively, the cooling fluid and heat exchange media (hot fluid) may enter and discharge from opposite ends of the heat exchanger unit, for example, fluid supply entering the unit through front end plate 13 and discharging through back end plate 14. Various other combinations and arrangements of supply and discharge are known in the art.

[0027] The cooling media is separated from one or more hot fluids by the heat exchange plates 12. Each plate 12 contains a gasket (not shown) that fits into grooves pressed in the plate and in the nozzle ports. The gasket prevents the two fluids from mixing. The gasket may be vented to the atmosphere to permit leaks to be readily detected. The heat exchange plates 12 are sandwiched between the front end plate 13 and the back end plate 14 by tie bolts 15. The plurality of heat exchanger plates together form plate package 11. The tie-bolts 15 may include screw-threads and the plate package 11 may, therefore, be compressed by nuts 17 threaded on to the tie-bolts 15. The number of tie-bolts 15 employed typically varies depending on the specific design and application of the plate heat exchanger 10, as is known in the art.

Alternatively, the plates 12 together with the end plates 13 and 14 may be brazed to a plate package where the braze joints keep the plate package together and maintain the required pressure needed for the assembly.

[0028] Plate heat exchangers involve at least two fluids, a first fluid acting as a cold or cooling media, and a second fluid as the hot media. Additional fluids may also be served by the plate heat exchanger depending on the heat load and heat transfer requirements of the fluids involved. For example, a plate heat exchanger may use a cooling agent, such as raw water, to service two separate hot media, such as one circuit of lube oil, and a second circuit of engine jacket water.

[0029] The heat transfer in a plate heat exchanger is primarily accomplished with heat exchange plates 12. Heat exchange plates 12 may vary in design, as is commonly known in the art, and typically include a thin sheet of metal precision pressed into corrugated patterns or chevrons. The corrugation pattern, depth, shape and angle are specific to individual manufacturers.

[0030] Each heat exchange plate 12 also includes a first liquid supply port 26, a first liquid discharge port 27, and at least a second liquid supply port 28 and a second liquid discharge port 29. As can be seen in Figs. 1 and 5, when heat exchange plates 12 are arranged together to form heat plate package 11, the first liquid supply ports 26 of each plate form a first liquid supply channel 36 through the heat plate package 11.

Similarly, first liquid discharge channel 37, second liquid supply channel 38, and second liquid discharge channel 39 are formed through heat plate package 11.

[0031] The flow paths of the first liquid and second liquid may vary according to the design of the plate heat exchanger. In an implementation, the supply and discharge of the first and second liquids may flow through the front end plate 13. As such, front end plate 13 includes first liquid supply port 46, first liquid discharge port 47, second liquid supply port 48, and second liquid discharge port 49. Additionally, an inspection or access port may be provided on back end plate 14. Fig. 1 illustrates back end port 57 arranged to provide access to first liquid discharge channel 37 through back end plate 14. Alternatively, an inspection or access port similar to back end port 57 may be arranged to provide access to any of the supply or discharge channels running through heat plate pack 11 , such as first liquid supply channel 36, second liquid supply channel 38 or second liquid discharge channel 39. Those skilled in the art will appreciate that an access port may be arranged on either front end plate 13 or back end plate 14 depending on the supply and discharge arrangements of the fluids involved.

[0032] Those skilled in the art will appreciate that any number of fluid channels may be formed in heat plate package 11. Additional fluid channels may be added to existing heat plate exchangers by adding a partition plate and the appropriate number of properly configured heat exchange plates 12 as are required for the additional heat load as well as properly configured end plates. This process, however, requires reconfiguration of the plate package, adds additional weight and bulk to the plate heat exchanger, and may be cost prohibitive.

[0033] In one implementation, a conduit heat exchanger 100 is configured to fit into, for example, either first liquid supply channel 36, first liquid discharge channel 37, second liquid supply channel 38, or second liquid discharge channel 39, thereby allowing for the inclusion of an additional heat exchange fluid circuit without the aforementioned additional heat exchange plates to the plate heat exchanger unit. By utilizing the previously unused space in the fluid flow channels of the plate heat

exchanger unit, the current invention provides an economical and space saving solution for cooling or heating particular fluids as described in more detail below.

[0034] As shown in Fig. 2, conduit heat exchanger 100 includes U-tube conduit 110 having a conduit supply portion 114, conduit bend 116, and conduit return portion 118. U-tube conduit 110 secures to connecting flange 102 by fixing supply portion 114 through flange supply port 104 and return portion 118 to flange return port 108. Extending outwardly from supply port 104 is supply connection 124. Supply connection 124 is configured to be connected to an auxiliary fluid supply source line 134. Also extending outwardly from flange return port 108 is return connection 128. Return connection 128 is configured to be connected to an auxiliary fluid return service line 138. Connections 124 and 128 to auxiliary fluid lines 134 and 138 may be by any conventional means including brazing, welding, flexible connection, quick-release connection, threaded connection, or the like.

[0035] Referring to Fig. 3, U-tube conduit 110 may alternatively include surface- enlarging features, for instance in the forms of extensions 111, which are provided on the conduit supply portion 114 and conduit return portion 118. Extensions 111 extend substantially radially outwardly from U-tube conduit 110. Variations of extensions 111 are commonly known in the art and contemplated herein. It is also possible to achieve a surface enlarging effect on U-tube conduit 110 in other ways, for instance through embossing of the surface of the conduit portions 114, 116, and 118. Such surface enlarging features allow for more efficient heat transfer between the liquid surrounding the U-tube conduit 110 and the fluid flowing through U-tube conduit 110. Alternatively, Fig. 4 depicts conduit portion 110 constructed with an extended path which is significantly longer than double the distance between connecting flange 102 and conduit bend portion 116.

[0036] Conduit heat exchanger connecting flange 102 is further configured to secure over a port on front end plate 13 or back end plate 14. For example, connecting flange 102 may be secured to first liquid discharge port 47, or back end port 57. Securing connecting flange 102 to a port on front end plate 13 or back end plate 14 may be by any conventional means including welding, brazing, bolting, or

the like. Flange 102 may also be secured to a port on front end plate 13 or back end plate 14 by threading flange 102 and receivable threading the port on front end plate 13 or back end plate 14. A gasket may be included between flange 102 and around the port on front end plate 13 or back end plate 14 to ensure the first or second liquid of heat exchanger 10 does not leak through the connection between flange 102 and end plate 13 or 14.

[0037] In an implementation to provide cooling to the auxiliary fluid flowing through conduit heat exchanger 100, conduit heat exchanger 100 is connected to end plate port 57 so as to be in communication with either first fluid discharge channel 37 or first fluid supply channel 36, such that U-tube conduit 110 extends substantially into either first fluid discharge channel 37 (as shown in Fig. 5) or first fluid supply channel 36 (not shown). The first fluid typically serves as the cold or cooling media in the plate heat exchanger. The first fluid is often fresh water, sea water, raw water, or cooling tower water, but may be any other fluid suitable for the requirement of the machinery arrangement involved.

[0038] In operation of an embodiment utilizing an auxiliary fluid cooling circuit, an auxiliary fluid flows from the auxiliary fluid supply line 134 through supply connection 124 into conduit supply portion 114 and returns through conduit return portion 118 through return connection 128 and into auxiliary fluid return line 138. U- tube 110, being located in first fluid discharge channel 37, is surrounded by the cooling media of the first fluid and heat transfer occurs between the warmer auxiliary fluid and the cooler first fluid. The auxiliary fluid may be any fluid suitable for the typical machinery arrangement involved including but not limited to; diesel oil, fuel oil, machinery lubrication oil, hydraulic fluid, purification system supply or return oil, cargo oil, cargo fluid, fresh water, sea water, black water, grey water, potable water, waste water, or any other liquid servicing a particular machinery arrangement.

[0039] In an alternate arrangement (not shown) to provide warming to the auxiliary fluid flowing through conduit heat exchanger 100, conduit heat exchanger 100 is connected to end plate port 57 so as to be in communication with either second fluid discharge channel 39 or second fluid supply channel 38, such that U-tube

conduit 110 extends substantially into either second fluid discharge channel 39 or second fluid supply channel 38. The second fluid typically serves as the hot media in the plate heat exchanger. The second fluid may be any fluid suitable for the requirement of the machinery arrangement involved, including, but not limited to machinery lube oil, jacket cooling water, other fresh water, hydraulic fluid, cargo fluid, or any other heated fluid.

[0040] hi operation of such an alternative arrangement utilizing an auxiliary fluid warming circuit, an auxiliary fluid flows from the auxiliary fluid supply line 134 through supply connection 124 into conduit supply portion 114 and returns through conduit return portion 118 through return connection 128 and into auxiliary fluid return line 138. U-tube 110, being located in second fluid discharge channel 39 or second fluid supply channel 38, is surrounded by the hot media of the second fluid and heat transfer occurs between the warmer second fluid and the cooler auxiliary fluid. The auxiliary fluid may be any fluid suitable for the typical machinery arrangement involved including but not limited to; diesel oil, fuel oil, machinery lubrication oil, hydraulic fluid, purification system supply or return oil, cargo oil, cargo fluid, fresh water, sea water, black water, grey water, potable water, waste water, or other liquid.

[0041] Because U-tube conduit 110 and parts of connection flange 102 of conduit heat exchanger 100 are immersed and surrounded by either the first fluid or second fluid of a typical heat exchanger, U-tube conduit 110 may include a sacrificial anode such as zinc. Additionally, U-tube conduit 110 and connection flange 102 are made of any material suitable for immersion in either fresh or salt water, or other liquids such as lube oil, cargo oil, fuel oil, black, grey or waste water, cargo fluid, or hydraulic fluid. Materials suitable for the manufacture of U-tube conduit 110 and connection flange 102 include materials comprising titanium, titanium alloys, copper- nickel alloys, bronze and bronze alloys, stainless steal, or nickel-molybdenum- chromium alloys, such as C-276.

[0042] In another implementation, depicted in Fig. 6 and 7, multi-circuit plate heat exchanger 600, accommodates a first fluid cooling media, a second fluid hot

media, and a third fluid hot media. The arrangement of multi-circuit plate heat exchanger 600 is similar to the plate heat exchangers described above, but includes an additional hot fluid circuit and illustrates the supply and discharge of the third fluid through the back end plate.

[0043] Multi-circuit plate heat exchanger 600 includes front end plate 613, two or more heat exchange plates 612, partition plate 609 and back end plate 614. Front end plate 613 includes first fluid supply port 646, first fluid discharge port 647, second fluid supply port 648 and second fluid discharge port 649. Back end plate 614 includes third fluid supply port 650 and third fluid discharge port 651. Partition plate 609 is configured to allow the first fluid cooling media to flow through the partition plate to the remaining plate heat exchangers as is commonly known in the art.

[0044] Heat exchanger plates 612 are configured to receive the first fluid through first fluid supply port 636 and discharge the first fluid through first fluid discharge port 637. The second fluid flows into heat exchanger plates 612 through second fluid supply port 638 and discharges through second fluid discharge port 639. The third fluid flows into heat exchanger plate 612 through third fluid supply port 640 and discharges through third fluid discharge port 641 (not shown).

[0045] When heat exchanger plates 612 are assembled into heat plate package 611, first fluid supply ports 636 form first fluid supply channel 626 in plate package 611 and are aligned with first fluid supply port 646 on front end plate 613. Similarly; first fluid discharge ports 637 form 'first fluid discharge channel 627 and are aligned with first fluid discharge port 647 on front end plate 613; second fluid supply ports 638 form second fluid supply channel 628 and are aligned with second fluid supply port 648 on front end plate 613; second fluid discharge ports 639 form second fluid discharge channel 629 and are aligned with second fluid discharge port 649 on front end plate 613; third fluid supply ports 640 form third fluid supply channel 630 and are aligned with third fluid supply port 650 on back end plate 614; and third fluid discharge ports 641 (not shown) form third fluid discharge channel 631 and are aligned with third fluid discharge port 651 on back end plate 614. One or more tie

bolts 615 may be used to compress the end plates and heat plate package, as previously described and known in the art.

[0046] Back end plate 614 may be fitted with a first fluid access port 687 configured to align with and be in communication, for example, with first fluid discharge channel 627. In an arrangement to provide after cooling to an auxiliary fluid, conduit heat exchanger 680, similar to the conduit heat exchanger previously described, is connected to fit in and through first fluid access port 687 and extend at least partially into first fluid discharge channel 627. hi operation, as the relatively warm auxiliary fluid flows through conduit heat exchanger 680, heat is transferred to the relatively cool first fluid discharging through first fluid discharge channel 627 and flowing around conduit heat exchanger 680. Alternatively, first fluid access port may be positioned on back end plate 614 to align with first fluid supply channel 626. Back end plate 614 may also be configured with multiple access ports, for example, one access port aligned with first fluid discharge channel 627 and a second access port aligned with first fluid supply channel 626.

[0047] hi another implementation, plate heat exchanger 10 includes supply and discharge pipes for the first fluid (cooling media) and the second fluid (hot media). As depicted in Fig. 8, first fluid discharge pipe 767 is connected by known means to first fluid discharge port 47 on front end plate 13. Conduit heat exchanger 100 may be connected to first fluid discharge pipe 767 via a flange, end plate, or strainer 768 as is known in the art. After conduit heat exchanger 100 is connected to first fluid supply pipe 767, U- tube conduit 110 may extend through first fluid discharge pipe 767, through first fluid discharge port 47 and into first fluid discharge channel 27. Alternatively U-tube conduit 110 may extend into first fluid discharge pipe 767 without extending into first fluid discharge channel 27. Similarly, conduit heat exchanger 100 may be connected to supply and discharge pipes associated with first fluid supply and second fluid supply and discharge ports.

[0048] Those skilled in the art will appreciate that one or more conduit heat exchangers may be fitted to a plate heat exchanger in order to provide one or more cooling or heating circuits to a plate heat exchanger without reconfiguration of the

plate pack. For example, a conduit heat exchanger may be fitted to the cooling media discharge circuit and a conduit heat exchanger may be fitted to the hot media supply circuit, as discussed above, thereby resulting in an implementation with both an after- cooling and pre-heating arrangement.

Example 1

[0049] In a practical example of an implementation, and referring to Fig. 9, a plate heat exchanger is used to cool engine lube oil and after-cool engine diesel oil. Seawater is used as the first fluid cooling medium. Cold seawater enters heat plate heat exchanger 200 through seawater supply port 246 and flows through sea water supply channel 226, which is in communication with heat plates 212. After flowing through heat plates 212, the relatively warm seawater flows through seawater discharge channel 227, and exits plate heat exchanger 200 through seawater discharge port 247. Hot engine lube oil lube enters plate heat exchanger 200 through lube oil supply port 248 and flows through lube oil supply channel 228, which is in communication with heat plates 212. As hot lube oil flows through heat plates 212 heat flows from the hot lube oil to the cold seawater. The now relatively cooler engine lube oil flows out of heat plates 212, through the lube oil discharge channel and exits plate heat exchanger 200 through lube oil discharge port 249.

[0050] Conduit heat exchanger 300 is fixedly connected through back end port 257 and is in communication with seawater discharge channel 227. Diesel oil coming from the diesel engine fuel injectors is preferably cooled before returning to the diesel service tank or holding tank. In accordance with one preferred embodiment of the present invention, hot diesel fuel oil flows through diesel return line 270 and into conduit heat exchanger 300 through conduit heat exchanger supply connection 324. As the hot diesel oil flows through U-tube conduit 310 heat is released from the relatively cool sea water flowing around and past U-tube conduit 310 in sea water discharge channel 227. The cooler diesel oil then flows out of U-tube conduit 310 through conduit heat exchanger discharge connection 328 and into diesel oil return line 271 for return to the diesel oil service tank or holding tank.

[0051] In similar implementations, other fluids may be cooled through conduit heat exchanger 300 of plate heat exchanger 200, including: fluids from a ship's propulsion machinery such as main and auxiliary propulsion diesels; maneuvering machinery such as hydraulic thrusters, steering gear, and windlass equipment; and a ship's auxiliary equipment such as ship's service and emergency diesel generators, service and auxiliary boilers, evaporators, oil purifiers, cargo transfer equipment, and the like. Specific fluids that may be after cooled in accordance with the present invention include: diesel oil, fuel oil, machinery lubrication oil, hydraulic fluid, purification system supply or return oil, cargo oil, cargo fluid, fresh water, sea water, black water, grey water, potable water, waste water, or any other liquid servicing a particular machinery arrangement.

Example 2

[0052] In a practical example of an implementation, and referring to Fig. 10, a plate heat exchanger is used to cool engine lube oil and pre-heat evaporator feed water. Seawater is used as the first fluid cooling medium. Cold seawater enters heat plate heat exchanger 200 through seawater supply port 246 and flows through seawater supply channel 226, which is in communication with heat plates 212. After flowing through heat plates 212, the relatively warm seawater flows through seawater discharge channel 227, and exits plate heat exchanger 200 through seawater discharge port 247. Hot engine lube oil lube enters plate heat exchanger 200 through lube oil supply port 248 and flows through the lube oil supply channel, which is in communication with heat plates 212. As hot lube oil flows through heat plates 212 heat flows from the hot lube oil to the cold sea water. The now relatively cooler but still warm engine lube oil flows out of heat plates 212, through lube oil discharge channel 229 and exits plate heat exchanger 200 through lube oil discharge port 249.

[0053] Conduit heat exchanger 400 is fixedly connected through back end port 257 and is in communication with lube oil discharge channel 229. Evaporator feed water is preferably pre-heated before it flows into the evaporator. In accordance with one aspect of the present invention, cold evaporator feed water flows through evaporator feed water supply line 470 and into conduit heat exchanger 400 through

conduit heat exchanger supply connection 424. As the cold evaporator feed water flows through U-tube conduit 410, heat is released from the relatively hot lube oil flowing around and past U-tube conduit 410 in lube oil discharge channel 229. The warmed evaporator feed water then flows out of U-tube conduit 410 through conduit heat exchanger discharge connection 428 and into evaporator feed water supply line 271, and ultimately into the ship's evaporator.

[0054] In similar implementations, other fluids may be pre-heated through conduit heat exchanger 400 of plate heat exchanger 200, including: fluids used in a ship's propulsion machinery such as main and auxiliary propulsion diesels; maneuvering machinery such as hydraulic thrusters, steering gear, and windlass equipment; and a ship's auxiliary equipment such as ship's service and emergency diesel generators, service and auxiliary boilers, evaporators, oil purifiers, cargo transfer equipment, and the like. Specific fluids that may be pre-heated in accordance with the present invention include: diesel oil, fuel oil, machinery lubrication oil, hydraulic fluid, purification system supply or return oil, cargo oil, cargo fluid, fresh water, seawater, black water, grey water, potable water, waste water, or any other liquid servicing a particular machinery arrangement.

[0055] Those skilled in the art will appreciate that the various aspects of the present invention may be applied to any number of engineering arrangements, are not limited to the marine or shipboard environment, and may be applied, for example, to power generation applications utilizing cooling tower water as the cooling medium. Other applications may include, without limitation, pasteurization and food preparation processes, chemical and petroleum manufacturing and processing, pharmaceutical processing, and other industrial or engineering applications requiring an efficient, low cost addition of a fluid circuit to a plate heat exchanger.

[0056] The foregoing description is intended to illustrate various aspects of the present invention. It is not intended that the examples presented herein limit the scope of the present invention. The invention now being fully described, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the appended claims.