Claims:We claim:
1. A hand primer (50) for a fuel feed pump (20), said hand primer (50) comprises
? a hollow primer-body (52) with a first reduction-joint (55) at its first end for coupling said primer-body (52) with said fuel feed pump (20);
? a handle (54) attached to a second end of said primer-body (52), characterized in that
? said primer-body (52) and said first reduction-joint (55) are made as a single piece.
2. The hand primer (50) of claim 1, wherein the primer-body (52) and the first reduction-joint (55) are made of a first material.
3. The hand primer (50) of claim 2, wherein the first material is steel.
4. The hand primer (50) of claim 1, wherein the handle (54) is made of a plastic material, a steel and the like.
5. The hand primer (50) of claim 1, further comprises a second reduction-joint (56) at second end of said primer-body (52) for attaching said handle (54) with said primer-body (52).
6. The hand primer (50) of claim 5, wherein said second reduction-joint (56) comprises a thread for attaching with the handle (54).
7. The hand primer (50) of claim 5, wherein said second reduction-joint (56) comprises an O-ring for sealing the second end of the primer-body (52).
8. The hand primer (50) of claim 1, wherein the second reduction-joint (56) is made of a second material compatible to said material of the handle (54).
9. The hand primer (50) of claim 1, wherein said handle (54) comprises a connecting shaft (57) and a plunger (58).
10. The hand primer (50) of claim 9, wherein said handle (54) is fitted to the primer-body (52) through said second reduction-joint (56) such that the connecting shaft (57) and the plunger (58)reciprocate inside the primer-body (52). , Description:Field of the invention:
[0001] The invention relates to a hand primer for a fuel feed pump. More specifically, it relates to a hand-operated priming pump for the fuel feed pump used in fuel injection system.
Background of the invention:
[0002] Feed pump is attached to the fuel injection pump for supplying fuel from the fuel tank to the fuel injection pump. The fuel injection pump supplies pressurized fuel to the engine of a vehicle.
[0003] Hand primers are used in the fuel feed pumps for supplying fuel from the fuel tank to the fuel feed pump and the fuel injection pump, whenever the fuel supply fails due to air lock. For instance, when the fuel tank is completely empty, air enters to the fuel passages. This trapped air interrupts the supply of fuel even after refilling of the fuel to the tank. The hand primer is operated manually to release the trapped air and supply the fuel from the tank during such circumstances.
[0004] The conventional hand primer consists of a primer-body which is attached to the feed pump through a reduction joint. This reduction joint is attached to the primer-body by a threaded connection and a rubber washer. Additionally, a sealant glue is also being used over the threaded connection. This increases the number of components involved and also the operations. However, leakage of fuel can happen over this joint occasionally in case of insufficient tightening or improper application of sealant since this is a manual process resulting in increase in time and cost involved.
Brief description of the invention:
[0005] The invention discloses a hand primer for a fuel feed pump. The hand primer comprises a hollow primer-body with a first reduction-joint at its first end for coupling the primer-body with the fuel feed pump. A handle is attached to a second end of the primer-body. The handle is made of a plastic material, a steel and the like.
[0006] The primer-body and the first reduction-joint are made as a single piece. Further the primer-body and the first reduction-joint are made of a first material such as steel.
[0007] The hand primer further comprises a second reduction-joint at second end of the primer-body for attaching the handle with the primer-body. The second-reduction-joint comprises a thread for attaching with the handle. The second reduction-joint also comprises an O-ring for sealing the top end of the primer-body. Further, the second reduction-joint is made of a second material compatible to said material of the handle.
[0008] Further the handle comprises a connecting shaft and a plunger. The handle is fitted to the primer-body through the second reduction-joint such that the connecting shaft and the plunger reciprocate inside the primer-body.
Brief description of the accompanying drawings:
[0009] An embodiment of the invention is described with reference to the following accompanying drawings,
[00010] Fig. 1 shows a schematic diagram of a fuel injection system with a mechanically governed fuel injection pump in accordance with an embodiment of the invention;
[00011] Fig. 2 shows an expanded view of a fuel injection pump with a fuel feed pump in accordance with an embodiment of the invention; and
[00012] Fig. 3 illustrates schematic diagram of a hand primer in accordance with an embodiment of the invention.
Detailed description of the embodiments:
[00013] Fig. 1 shows a schematic diagram of a fuel injection system with a mechanically governed fuel injection pump in accordance with an embodiment of the invention. The fuel injection system 100 has a fuel tank 10 from which fuel is drawn by a fuel feed pump 20. The fuel feed pump 20 is part of a fuel injection pump 30. Fuel is supplied to the fuel injection pump 30 by the fuel feed pump 20 through a filter 25. Fuel is then supplied to an engine 40 by the fuel injection pump 30 through a high-pressure fuel line 35.
[00014] Fig. 2 shows an expanded view of a fuel injection pump with a fuel feed pump in accordance with an embodiment of the invention. The fuel injection pump 30 has a fuel feed pump 20. The fuel feed pump 20 can be screwed or attached by suitable means to the fuel injection pump 30. The figure 2 also shows an exploded perspective view of a hand primer 50. The hand primer 50 is attached to the fuel feed pump 20.
[00015] Sometimes, air gets locked in the fuel supply line between the fuel feed pump 20, a fuel injection pump 30 and the fuel supply line. As a result, fuel supply to the engine 40 is hindered. For example, whenever the fuel is completely empty in the fuel tank 10, air may get trapped in the fuel supply line. Even after the fuel is refilled in the fuel tank 10, the fuel supply to the engine 40 may be interrupted. Hence the hand primer 50 is used to manually purge out the trapped air and helps out in the fuel supply. The hand primer 50 has a hollow primer-body 52 and a handle 54. The handle 54 is unscrewed from the second reduction joint 56 of Fig.3 which is attached to the primer-body 52 and manually reciprocated to purge out the trapped air.
[00016] Fig. 3 illustrates schematic diagram of a hand primer in accordance with an embodiment of the invention. The hand primer 50 is also called as manually operated or hand operated priming pump 50. The hand primer 50 comprises a hollow primer-body 52. The primer-body 52 is shown with an inserted sleeve in the figure. The primer-body 52 has a first reduction-joint 55 at its first end for coupling it to the fuel feed pump 20. The handle 54 is attached to the primer-body 52 through the connecting rod 57 and the plunger 58 assembly at its second end. In an embodiment of the invention, the first end is a bottom end and the second end is the top end of the primer-body 52. The primer-body 52 and the first reduction-joint 55 are made as a single piece or as an integral body. Also, the primer-body 52 and the first reduction-joint 55 are made of a first material such as steel. Since the primer-body 52 and the first reduction-joint 55 are made as an integral piece, the need for threaded connection between the primer-body 52 and the first reduction-joint 55 is avoided. As a result, the chances of leakage over the connection joint are eliminated. Further, the need for applying a glue over the joint is avoided. Further need for a rubber gasket is eliminated. Also, operational cost and time are reduced considerably.
[00017] The primer-body 52 also comprises a second reduction-joint 56 at its second end for attaching the handle 54 with the primer-body 52. In an embodiment of the invention, the second reduction joint 56 can be press-fitted to the primer-body 52.
[00018] The second reduction-joint 56 comprises a thread for attaching the handle 54. Further an O-ring is provided in the second reduction-joint 56 for sealing the second end of the primer-body 52. The chances of fuel entering the second end of the primer-body 52 is less. Further the O-ring avoids the leakage of fuel through the second end.
[00019] In an embodiment of the invention, the handle 54 is made of plastic material to save cost. The second reduction joint 56 made of a second material such as PA66 (Poly Amide 66) material which is compatible with the material of the handle 54.
[00020] Alternatively, when the handle 54 is made of steel, the second reduction-joint 56 is also made of steel or a similar material compatible to that of the handle 54.
[00021] The handle 54 has a connecting shaft 57 and a plunger 58. The handle is fitted to the primer-body 52 through the second reduction joint 56 such that the connection shaft 57 and plunger 58 reciprocate inside the primer-body 52. That is, the plunger 58 can be reciprocated inside the primer-body 52 by a push-pull action using the handle 54 for purging out the air trapped inside the fuel supply line.
[00022] The hand primer 50 avoids the two-piece construction and threaded connections, hence simplifies the construction and reduces the required cost and time. Fuel leakage problem at the first end or the bottom end of the primer body 52 is prevented as the threaded connection is eliminated.
[00023] Further, the need for glue material and machining operations (for instance machining for external threading on the body 52 and the internal threading on reduction joint 55) is avoided. Further the rubber gasket is eliminated. The present invention enables the use of plastic handle 54, thereby further cost reduction is enabled.
[00024] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.