CA1120355A - Double walled fuel line - Google Patents
Double walled fuel lineInfo
- Publication number
- CA1120355A CA1120355A CA000363267A CA363267A CA1120355A CA 1120355 A CA1120355 A CA 1120355A CA 000363267 A CA000363267 A CA 000363267A CA 363267 A CA363267 A CA 363267A CA 1120355 A CA1120355 A CA 1120355A
- Authority
- CA
- Canada
- Prior art keywords
- tube
- fuel
- bore
- annular space
- fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Fuel-Injection Apparatus (AREA)
Abstract
DOUBLE WALLED FUEL LINE
ABSTRACT OF THE DISCLOSURE
A double walled fuel line for use with fuel injection engines including first and second, nominally concentric tubes having an annular space therebetween. Both of the tubes are bendable on conventional tube bending equipment and the inner-most tube mounts fittings for connection into a fuel injec-tion system. An additional fitting associated with the outer-most tube establishes fluid communication to the annular space between the tubes for venting leaking fuel.
ABSTRACT OF THE DISCLOSURE
A double walled fuel line for use with fuel injection engines including first and second, nominally concentric tubes having an annular space therebetween. Both of the tubes are bendable on conventional tube bending equipment and the inner-most tube mounts fittings for connection into a fuel injec-tion system. An additional fitting associated with the outer-most tube establishes fluid communication to the annular space between the tubes for venting leaking fuel.
Description
11;~035~
eACKGROUND OF l'HE INVENTI ON
This invention relates to fuel lines for use in fuel injection systems to interconnect a fuel pump and an injection nozzle.
Fuel injec~ion pumps employed in fuel injection systems generate extremely high hydraulic pressures which may range upwardly from several thousand pounds per square inch.
The pressures are generated in pulse form to direct fuel from the pump through fuel lines to injection nozzles, typically associated with engines or the like. Because of rapid cycling and/or vibration associated with the power plant with which the injection system may be used, there may be a tendency for fittings to loosen and/or conduits to fracture under the pressures involved.
In the case of either, fuel spillage will occur and such spillage is particularly undesirable where the engine is operating in an enclosed area and/or substantially unattended thereby causing combustible vapors to form and/or permitting a sizable accumulation of fuel to occur in an area where it is unlikely to be discovered.
To avoid such difficulties, it has been suggested to provide double walled fuel lines so that if the fuel carrying conduit ruptures, lost fuel will be captured by an outer conduit to prevent leakage. This approach eliminates leakage due to fuel line rupture but does not prevent leakage due to loosening of interengaging parts which are intended to be sealed.Moreover, heretofore, this approach has been practiced using rigid, precisely dimensioned, unbendable pipes or the like, thereby making it extremely difficult to route fuel lines from an injection pump to an injection nozzle.
11~035S
SUMMARY OF THE INVENTION
According to one feature of the present invention, there is provided a double-walled fluid pressure line comprising a first tube having opposed ends, axially oppositely directed, radially outwardly facing sealing surfaces on the ends of the first tube; a pair of washers one on each end of the first tube disposed just axially inwardly of the respective sealing surface; a pair of nuts one on each end of the first tube and rotatable thereon, the nuts housing respective ones of the washers and the sealing surfaces; a second tube nominally concentrically disposed around the first tube in spaced relation thereto to define an elongate annular space, characterized in that at least one of the washers has a greater radius than the corresponding sealing surface and an axially extending passage extending therethrough; the axially extending passage providing a path for fluid, leaking in use from between the corresponding sealing surface and a complementary surface of a part to which the corresponding end of the first tube is coupled, from the leak to a port venting the annular space.
Thus, any fuel leaking from the inner tube into the outer tube is returned safely to the source this minimizing the danger of fluid pressure build up in the fuel line. Furthermore, if the leak is only small the line can continue to function whilst returning excess, leaking, fuel to the source.
The fuel source may comprise a reservoir or tank alone or may include a fluid pump as well in which case the outer tube may return fuel to the low pressure side of the pump or to the reservoir or tank.
11;~0355 Preferably, the supply line is bendable, the inner tube being deformable into a required configuration and the outer tube being resilient to allow it to flex around bends in the inner tube to maintain an open return path to the source.
Other features and advantages will become apparent from the following specification taken in connection with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic view of an engine plant;
Fig. 2 is an axial sectional view of one fuel supply line;
Fig. 3 is an enlarged view of one end of the fuel line; and Fig. 4 is a sectional view illustrating a typical relationship of the components of the inventive fuel line when bent.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Fuel lines made according to the invention are intended to be utilized, for example, with an engine 10 supplied with fuel from a tank 12. The tank 12 has a conduit 14 extending to a conventional fuel injection pump 16 which, in turn, provides fuel under pressure and in pulse form in a desired sequence to a plurality of fuel lines 18, to be described, which convey the fuel to conventional fuel injection nozzles 20 associated with the engine 10. As will be seen, the fuel lines 18 are double walled and are provided with means which direct leaking fuel to a conduit 24 by which it may be returned to the tank 12 or, alternatively, to the input of the injection pump 16, or to an alarm 28.
lhe fuel lines 18 are adapted to so return leaked fuel if the fuel leakage occurs either due to rupture or to leakage at the fittings.
With the foregoing in mind, one embodiment of a fuel line made according to the invention will be described in greater detail with reference to Figs. 2-4, inclusive.
The fuel line includes a first, elongated, metallic rigid tube 30 which has a wall thickness sufficient to withstand the high pressures generated by the pump 16. lhe precise wall thickness will depend upon the inner diameter of the tube 30 which, in turn, will be dependent upon the pressures generated as well as fuel delivery requirements and are well known in the art, forming no part of the present invention. In the overwhelming majority of cases,i such criteria will result in the tube 30, while rigid, being bendable by conventional tube bending equipment.
Each end of the tube 30 is provided with a seallng surface 32 which, as illustrated, is frusto-conical such that the two surfaces 32 are opposed from each other and oppositely axially directed. They also face radially outwardly. The surfaces 32 are formed integrally on the tube 30 after other components to be described are assembled thereon. In the usual case, the surfaces 32 will be formed by cold forming as swaging. Just axially )355 inwardly of each of the surfaces 32 is a shoulder 34, also cold formed, against which a sealing washer 36 is abutted. The washers 36 will typically be formed of steel or iron and will not deteriorate upon exposure to petroleum products.
It will be observed from Fig. 3 that each sealing washer 36 extends radially outwardly from the radially outer extent 38 of each sealing surface 32 for purposes to be seen.
The respective ends of the tube 30 are provided with nuts 40 and 41, each having an external hex head configuration (not shown) for conventional tightening purposes. The nut 40 has an interior threaded surface 42 by which the same may be affixed to a male fitting associated with either the pump 16 or nozzle 20, the male member being provided with a sealing surface that will mate with the sealing surface 32 at the associated end of the tube 30.
Oppositely of the threaded surface 42 is a radially inwardly directed shoulder 44 for purposes to be seen and intermediate the surface 42 and the shoulder 44, the nut 40 receives and houses both the associated washer 36 and the sealing surface 32.
The nut 41 is provided with a similar threaded surface 46 for capturing a threaded male member having a sealing surface designed to seal against the sealing surface 32 at the associated end 11;~0355 of the tubing 30 as well as a radially inwardly directed shoulder 48 which abuts the washer 36 at the associated tubing end with the intermediate portion of the nut hoùsing both the washer 36 and the sealing surface 32.
Axially inwardly of the shoulder 48 is an enlarged diameter bore 50. The end of the nut 41 remote from the internally threaded end 46 is of reduced diameter, as shown at 52, and is received within an enlarged diameter bore 54 within a fitting 56. A radially outwardly opening, peripheral groove 58 in the nut 41 receives an annular seal 60 to establish a seal at the interface between the fitting 56 and the nut 41.
The bore 54 extends to a reduced diameter bore 62 within the fitting 56. As illustrated, the tube 30 extends through both bores 62 and 50 and is of lesser diameter than either. Two radially directed ports 64 are provided with threads (not shown) and extend to the reduced diameter bore 62. One of the ports 64 is adapted to be connected to the conduit 24 of pump 16, or alarm 28, while the other will typically be provided with a removable plug for purposes to be seen.
The right-hand end of the fitting 56 is provided with a threaded, reduced diameter section 66 which receives the nut 68 of a conventional compression fitting.
A second, elongated, metal, rigid tube 70, bendable with conventional tube bending equipment, has an end 72 extending through the nut 68 and into the 11;~035S
reduced diamter bore 62. A conventional sealing sleeve 74 is disposed on the end 72 and within the nut 68 to partially enter the bore 62 as well. Consequently, upon tightening of the nut 68, the sleeve 74 sealingly engages both the outer diameter of the second tube 70 and the flared end 75 of the bore 62. The outer diameter of the tube 70 is just slightly less than the diameters of the bores 50 and 62. Thus, both the nut 41 and the fitting 56 may telescope onto the tube 70 to expose the ends of the tube 30 to allow forming of the surfaces 32 and shoulders 34.
Moreover, the tube 70 is circular in cross section as is the tube 30 and haæ an inner diameter greater than the outer diameter of the tube 30 and is nominally concentrically diæposed about the tube 30.
Because of the relationship of inner and outer diameters, an elongated, annular space 76 exists between the tubes 30 and 70. The end of the tube 70 remote from the end 72 is flared slightly as at 78 and is in abutment with the sealing washer 36 associated with the nut 40.
As a consequence of the foregoing, it will be appreciated that when the nuts 40 and 41 are secured to male members in the fuel injection system and the nut 68 is tightened, the ends of the tube 70 will be sealed to the tube 30 so that any rupture of the tube 30 will result in leaking fuel being directed to the annular space 76 to flow therethrough to the bore 62 and then via one of the ports 64 to the conduit 24 and ~.
11~0355 activate the alarm 28. The presence of fuel in the annular space 76 of any of tne lines may be visually observed by removing the plugs (not shown) associated with the other of the ports 64 to assist in determining the leaky line.
In order to direct leaking fuel due to looseness of interengaging sealing surfaces 32 to the conduit 24, one or both of the washers 36 may be provided with a small passage 80, as seen in Fig. 3.
The passage 80 extends generally axially through the washer 36 to establish fluid communication between the annular space 76 and a point radially outwardly of the radially outwardmost extent 38 of the sealing surfaces 34. Thus, any leaking fuel traveling along the surfaces 32 will ultimately reach the passage 80 to be directed to the conduit 24.
In order to provide a fuel line that is bendable on conventional tube bending equipment, the tube 70 is provided with a relatively thin wall. In most cases, the wall thickness will be on the order of about l mm. or less and, in a highly preferred embodiment, wherein the outer diameter of the tube 70 is slightly less than 0.4 inch, will be about 0.7 mm.
The tube 70 may be formed of steel or other similar materials.
Fig. 4 illustrates a typical cross section taken through the tubes 30 and 70 intermediate their ends after being bent by tube bending equipment. The surface 100 of the tube 70 engaged by the tool tends to flatten and immediately adjacent thereto, the 11;~0355 surface bulges as at 102 on opposite sides of the tube 70. The tube 30 is substantially nondistorted and is engaged at opposite sides by the tube 70. However, areas 10~ in the vicinity of the bulges 102 remain open as part of the annular space 76 to allow the flow of fuel to the conduit 24 in the manner previously described.
Thus, it will be appreciated that a fuel line made according to the invention ensures against fuel spillage due to either rupture of the main fuel line or leakage at sealed connections. It also provides the significant advantage of being bendable with conventional tube bending equipment without fear of blocking the flow path to the return line, thereby allowing easy installation without requiring precisely fitted pipes of the like.
A highly significant feature of the invention is the absence of interengaging structure extending between the tubes 30 and 70 within the annular space ~O 76. If such structure were present, deformation such as illustrated in Fig. 4 during bending of the fuel line would not occur, but rather, the structure would tend to collapse the first, thereby decreasing its fuel carrying capacity and interfering with proper operation of the injection system.
From the foregoing, it will be appreciated then that the invention provides a highly useful double walled fuel line for use with fuel injection systems.
eACKGROUND OF l'HE INVENTI ON
This invention relates to fuel lines for use in fuel injection systems to interconnect a fuel pump and an injection nozzle.
Fuel injec~ion pumps employed in fuel injection systems generate extremely high hydraulic pressures which may range upwardly from several thousand pounds per square inch.
The pressures are generated in pulse form to direct fuel from the pump through fuel lines to injection nozzles, typically associated with engines or the like. Because of rapid cycling and/or vibration associated with the power plant with which the injection system may be used, there may be a tendency for fittings to loosen and/or conduits to fracture under the pressures involved.
In the case of either, fuel spillage will occur and such spillage is particularly undesirable where the engine is operating in an enclosed area and/or substantially unattended thereby causing combustible vapors to form and/or permitting a sizable accumulation of fuel to occur in an area where it is unlikely to be discovered.
To avoid such difficulties, it has been suggested to provide double walled fuel lines so that if the fuel carrying conduit ruptures, lost fuel will be captured by an outer conduit to prevent leakage. This approach eliminates leakage due to fuel line rupture but does not prevent leakage due to loosening of interengaging parts which are intended to be sealed.Moreover, heretofore, this approach has been practiced using rigid, precisely dimensioned, unbendable pipes or the like, thereby making it extremely difficult to route fuel lines from an injection pump to an injection nozzle.
11~035S
SUMMARY OF THE INVENTION
According to one feature of the present invention, there is provided a double-walled fluid pressure line comprising a first tube having opposed ends, axially oppositely directed, radially outwardly facing sealing surfaces on the ends of the first tube; a pair of washers one on each end of the first tube disposed just axially inwardly of the respective sealing surface; a pair of nuts one on each end of the first tube and rotatable thereon, the nuts housing respective ones of the washers and the sealing surfaces; a second tube nominally concentrically disposed around the first tube in spaced relation thereto to define an elongate annular space, characterized in that at least one of the washers has a greater radius than the corresponding sealing surface and an axially extending passage extending therethrough; the axially extending passage providing a path for fluid, leaking in use from between the corresponding sealing surface and a complementary surface of a part to which the corresponding end of the first tube is coupled, from the leak to a port venting the annular space.
Thus, any fuel leaking from the inner tube into the outer tube is returned safely to the source this minimizing the danger of fluid pressure build up in the fuel line. Furthermore, if the leak is only small the line can continue to function whilst returning excess, leaking, fuel to the source.
The fuel source may comprise a reservoir or tank alone or may include a fluid pump as well in which case the outer tube may return fuel to the low pressure side of the pump or to the reservoir or tank.
11;~0355 Preferably, the supply line is bendable, the inner tube being deformable into a required configuration and the outer tube being resilient to allow it to flex around bends in the inner tube to maintain an open return path to the source.
Other features and advantages will become apparent from the following specification taken in connection with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic view of an engine plant;
Fig. 2 is an axial sectional view of one fuel supply line;
Fig. 3 is an enlarged view of one end of the fuel line; and Fig. 4 is a sectional view illustrating a typical relationship of the components of the inventive fuel line when bent.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Fuel lines made according to the invention are intended to be utilized, for example, with an engine 10 supplied with fuel from a tank 12. The tank 12 has a conduit 14 extending to a conventional fuel injection pump 16 which, in turn, provides fuel under pressure and in pulse form in a desired sequence to a plurality of fuel lines 18, to be described, which convey the fuel to conventional fuel injection nozzles 20 associated with the engine 10. As will be seen, the fuel lines 18 are double walled and are provided with means which direct leaking fuel to a conduit 24 by which it may be returned to the tank 12 or, alternatively, to the input of the injection pump 16, or to an alarm 28.
lhe fuel lines 18 are adapted to so return leaked fuel if the fuel leakage occurs either due to rupture or to leakage at the fittings.
With the foregoing in mind, one embodiment of a fuel line made according to the invention will be described in greater detail with reference to Figs. 2-4, inclusive.
The fuel line includes a first, elongated, metallic rigid tube 30 which has a wall thickness sufficient to withstand the high pressures generated by the pump 16. lhe precise wall thickness will depend upon the inner diameter of the tube 30 which, in turn, will be dependent upon the pressures generated as well as fuel delivery requirements and are well known in the art, forming no part of the present invention. In the overwhelming majority of cases,i such criteria will result in the tube 30, while rigid, being bendable by conventional tube bending equipment.
Each end of the tube 30 is provided with a seallng surface 32 which, as illustrated, is frusto-conical such that the two surfaces 32 are opposed from each other and oppositely axially directed. They also face radially outwardly. The surfaces 32 are formed integrally on the tube 30 after other components to be described are assembled thereon. In the usual case, the surfaces 32 will be formed by cold forming as swaging. Just axially )355 inwardly of each of the surfaces 32 is a shoulder 34, also cold formed, against which a sealing washer 36 is abutted. The washers 36 will typically be formed of steel or iron and will not deteriorate upon exposure to petroleum products.
It will be observed from Fig. 3 that each sealing washer 36 extends radially outwardly from the radially outer extent 38 of each sealing surface 32 for purposes to be seen.
The respective ends of the tube 30 are provided with nuts 40 and 41, each having an external hex head configuration (not shown) for conventional tightening purposes. The nut 40 has an interior threaded surface 42 by which the same may be affixed to a male fitting associated with either the pump 16 or nozzle 20, the male member being provided with a sealing surface that will mate with the sealing surface 32 at the associated end of the tube 30.
Oppositely of the threaded surface 42 is a radially inwardly directed shoulder 44 for purposes to be seen and intermediate the surface 42 and the shoulder 44, the nut 40 receives and houses both the associated washer 36 and the sealing surface 32.
The nut 41 is provided with a similar threaded surface 46 for capturing a threaded male member having a sealing surface designed to seal against the sealing surface 32 at the associated end 11;~0355 of the tubing 30 as well as a radially inwardly directed shoulder 48 which abuts the washer 36 at the associated tubing end with the intermediate portion of the nut hoùsing both the washer 36 and the sealing surface 32.
Axially inwardly of the shoulder 48 is an enlarged diameter bore 50. The end of the nut 41 remote from the internally threaded end 46 is of reduced diameter, as shown at 52, and is received within an enlarged diameter bore 54 within a fitting 56. A radially outwardly opening, peripheral groove 58 in the nut 41 receives an annular seal 60 to establish a seal at the interface between the fitting 56 and the nut 41.
The bore 54 extends to a reduced diameter bore 62 within the fitting 56. As illustrated, the tube 30 extends through both bores 62 and 50 and is of lesser diameter than either. Two radially directed ports 64 are provided with threads (not shown) and extend to the reduced diameter bore 62. One of the ports 64 is adapted to be connected to the conduit 24 of pump 16, or alarm 28, while the other will typically be provided with a removable plug for purposes to be seen.
The right-hand end of the fitting 56 is provided with a threaded, reduced diameter section 66 which receives the nut 68 of a conventional compression fitting.
A second, elongated, metal, rigid tube 70, bendable with conventional tube bending equipment, has an end 72 extending through the nut 68 and into the 11;~035S
reduced diamter bore 62. A conventional sealing sleeve 74 is disposed on the end 72 and within the nut 68 to partially enter the bore 62 as well. Consequently, upon tightening of the nut 68, the sleeve 74 sealingly engages both the outer diameter of the second tube 70 and the flared end 75 of the bore 62. The outer diameter of the tube 70 is just slightly less than the diameters of the bores 50 and 62. Thus, both the nut 41 and the fitting 56 may telescope onto the tube 70 to expose the ends of the tube 30 to allow forming of the surfaces 32 and shoulders 34.
Moreover, the tube 70 is circular in cross section as is the tube 30 and haæ an inner diameter greater than the outer diameter of the tube 30 and is nominally concentrically diæposed about the tube 30.
Because of the relationship of inner and outer diameters, an elongated, annular space 76 exists between the tubes 30 and 70. The end of the tube 70 remote from the end 72 is flared slightly as at 78 and is in abutment with the sealing washer 36 associated with the nut 40.
As a consequence of the foregoing, it will be appreciated that when the nuts 40 and 41 are secured to male members in the fuel injection system and the nut 68 is tightened, the ends of the tube 70 will be sealed to the tube 30 so that any rupture of the tube 30 will result in leaking fuel being directed to the annular space 76 to flow therethrough to the bore 62 and then via one of the ports 64 to the conduit 24 and ~.
11~0355 activate the alarm 28. The presence of fuel in the annular space 76 of any of tne lines may be visually observed by removing the plugs (not shown) associated with the other of the ports 64 to assist in determining the leaky line.
In order to direct leaking fuel due to looseness of interengaging sealing surfaces 32 to the conduit 24, one or both of the washers 36 may be provided with a small passage 80, as seen in Fig. 3.
The passage 80 extends generally axially through the washer 36 to establish fluid communication between the annular space 76 and a point radially outwardly of the radially outwardmost extent 38 of the sealing surfaces 34. Thus, any leaking fuel traveling along the surfaces 32 will ultimately reach the passage 80 to be directed to the conduit 24.
In order to provide a fuel line that is bendable on conventional tube bending equipment, the tube 70 is provided with a relatively thin wall. In most cases, the wall thickness will be on the order of about l mm. or less and, in a highly preferred embodiment, wherein the outer diameter of the tube 70 is slightly less than 0.4 inch, will be about 0.7 mm.
The tube 70 may be formed of steel or other similar materials.
Fig. 4 illustrates a typical cross section taken through the tubes 30 and 70 intermediate their ends after being bent by tube bending equipment. The surface 100 of the tube 70 engaged by the tool tends to flatten and immediately adjacent thereto, the 11;~0355 surface bulges as at 102 on opposite sides of the tube 70. The tube 30 is substantially nondistorted and is engaged at opposite sides by the tube 70. However, areas 10~ in the vicinity of the bulges 102 remain open as part of the annular space 76 to allow the flow of fuel to the conduit 24 in the manner previously described.
Thus, it will be appreciated that a fuel line made according to the invention ensures against fuel spillage due to either rupture of the main fuel line or leakage at sealed connections. It also provides the significant advantage of being bendable with conventional tube bending equipment without fear of blocking the flow path to the return line, thereby allowing easy installation without requiring precisely fitted pipes of the like.
A highly significant feature of the invention is the absence of interengaging structure extending between the tubes 30 and 70 within the annular space ~O 76. If such structure were present, deformation such as illustrated in Fig. 4 during bending of the fuel line would not occur, but rather, the structure would tend to collapse the first, thereby decreasing its fuel carrying capacity and interfering with proper operation of the injection system.
From the foregoing, it will be appreciated then that the invention provides a highly useful double walled fuel line for use with fuel injection systems.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A double-walled fluid pressure line comprising a first tube having opposed ends, axially oppositely directed, radially outwardly facing sealing surfaces on the ends of the first tube; a pair of washers one on each end of the first tube disposed just axially inwardly of the respective sealing surface; a pair of nuts one on each end of the first tube and rotatable thereon, the nuts housing respective ones of the washers and the sealing surfaces; a second tube nominally concentrically disposed around the first tube in spaced relation thereto to define an elongate annular space, characterized in that at least one of the washers has a greater radius than the corresponding sealing surface and an axially extending passage extending therethrough; the axially extending passage providing a path for fluid, leaking in use from between the corresponding sealing surface and a complementary surface of a part to which the corresponding end of the first tube is coupled, from the leak to a port venting the annular space.
2. A line according to claim 1, characterized in that one end of the second tube is captured within one of the nuts in substantial abutment with the associated washer which is substantially sealed to the first and second tubes, and the other end of the second tube being sealed to a fitting associated with the other of the nuts; the port being provided in the fitting; a bore in the fitting of larger cross-section than the first tube receiving the first tube and the second tube other end, the port extending to the bore to establish fluid communication between the port and the annular space for venting any fluid leaking into the annular space.
3. A line according to claim 2, characterized in that the first tube has a wall thickness sufficient to withstand high internal pressure and yet be bent on conventional tube bending equipment; and the second tube has a relatively thin wall so as to be bendable with the first tube on conventional tube bending equipment.
4. A line according to claim 3, characterized in that the fitting includes two ports each extending to the bore, one arranged to be connected to a vent for the annular space and the other being arranged to be selectively opened or closed to enable inspection to determine whether fluid is in the annular space.
5. A line according to claim 4, characterized in that a sealing sleeve is provided on the second tube other end engaging an end of the bore, a further nut on the second tube other end being screwed to the fitting about the bore to cause the sleeve to seal the bore to the second tube other end, the other end of the bore having an enlarged diameter partially receiving the other nut, and an annular seal sealing the interface of the bore and the other nut.
6. A line according to claim 5, characterized in that the annular space is free from structure extending between the tubes along substantially the length thereof.
7. A fluid fuel supply system including a double walled fluid pressure line according to claim 6.
8. A fluid fuel supply system according to claim 7, having a fuel source, characterized in that the inner tube of the line is connected to the source to receive fuel therefrom and that the port is separately connected back to the source to return any fuel passing into the second tube back to the source.
9. A fluid fuel supply system according to claim 8, in which the source comprises a reservoir and a pump, characterized in that the port is connected to one end of a pipe, the other end of the pipe being connected to the reservoir, the line being connected directly to the pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000363267A CA1120355A (en) | 1977-12-07 | 1980-10-24 | Double walled fuel line |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/858,226 US4149568A (en) | 1977-12-07 | 1977-12-07 | Double walled fuel line |
| US858,226 | 1977-12-07 | ||
| CA317,475A CA1099165A (en) | 1977-12-07 | 1978-12-06 | Double walled fuel line |
| CA000363267A CA1120355A (en) | 1977-12-07 | 1980-10-24 | Double walled fuel line |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1120355A true CA1120355A (en) | 1982-03-23 |
Family
ID=27166003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363267A Expired CA1120355A (en) | 1977-12-07 | 1980-10-24 | Double walled fuel line |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1120355A (en) |
-
1980
- 1980-10-24 CA CA000363267A patent/CA1120355A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |