JP2019157711A - Water feeding pump - Google Patents

Abstract

To provide a compact and inexpensive water feeding pump while avoiding water-based corrosion and damage of a compression spring for use in returning a plunger after discharging water to cause it to be returned back to a reference position.SOLUTION: A water feeding pump that is one preferred embodiment of this invention is provided with a pump case and a plunger to pressurize water to be discharged and discharge it by moving the plunger within the pump case to a discharge port side under utilization of pressure of hydraulic oil. The pump case comprises: a discharge water drain part for use in discharging water flowing down at a clearance between an outer peripheral surface of the plunger and an inner peripheral surface of the pump case; and a pneumatic spring for returning the plunger after discharging water to be discharged to a reference position before discharging water to be discharged by moving the plunger to the opposite side of the discharge port side of the pump case. The pneumatic spring is constituted in such a way that air of larger pressure than the inner pressure at the discharge water drain part is supplied to an air chamber enclosed by the outer peripheral surface of the plunger and the inner peripheral surface of the pump case at a lower position than the discharge water drain part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water injection pump.

  Conventionally, a fuel injection pump for injecting fuel into a cylinder is applied to a marine diesel engine mounted on a marine vessel. In general, a fuel injection pump includes a hollow cylindrical pump case and a plunger (piston) that can be reciprocated in the pump case. The plunger is placed on the discharge port side of the pump case using the pressure of hydraulic oil. By moving, the fuel is pressurized and discharged. The fuel discharged from the fuel injection pump is pumped through a pipe or the like to a fuel injection valve provided in the cylinder, and is injected from the injection port of the fuel injection valve into the combustion chamber in the cylinder.

  Further, as disclosed in, for example, Patent Document 1, the fuel injection pump includes a compression spring (coil spring) that biases the plunger on the side opposite to the discharge port side of the pump case. After the fuel is discharged as described above, the plunger moves in the direction in which the hydraulic oil is pushed out from the pump case by the urging force of the compression spring, and the original position before the fuel is discharged (hereinafter referred to as a reference position as appropriate). Return to).

JP 2017-31918 A

  By the way, in the field of ships, water technology has been proposed as one method for reducing nitrogen oxides (NOx) in exhaust gas discharged from marine diesel engines. In this water technology, by adding water to the combustion chamber in the cylinder, the combustion temperature of the fuel in the combustion chamber is lowered to reduce the NOx emission amount. In such water technology, water is usually injected into fuel before injection (fuel column existing in a fuel flow passage such as a fuel injection valve) or water is injected into the combustion chamber alone (injection). For this purpose, a hydraulically driven water injection pump using hydraulic oil pressure is applied.

  The hydraulically driven water injection pump can be simply configured by, for example, adopting the structure of the fuel injection pump described above and replacing the discharge target from fuel to water. However, in such a water injection pump, water remaining in the pump case may come into contact with the compression spring through a gap between the outer wall surface of the plunger and the inner wall surface of the pump case. In this case, the compression spring corrodes. There is a risk of damage. Even if the gap is sealed with a seal member, the plunger that reciprocates each time water is discharged repeatedly slides on the seal member, and if the seal member is worn or damaged, the seal of the gap may not be maintained. There is. For this reason, it is necessary to take measures to prevent corrosion and damage due to contact with water with respect to the compression spring for returning the plunger after discharging water to the reference position. For example, the corrosion of the compression spring can be prevented by taking measures such as using SUS as the material of the compression spring. However, in this case, the water injection pump main body becomes large, resulting in an increase in cost for the water injection pump. Furthermore, there exists a problem that the freedom degree of the arrangement space of a water injection pump falls.

  The present invention has been made in view of the above circumstances, and is small and inexpensive water injection while avoiding corrosion and damage due to water of a compression spring for returning a plunger after discharging water to a reference position. The object is to provide a pump.

  In order to solve the above-described problems and achieve the object, a water injection pump according to the present invention includes a pump case and a plunger provided in a reciprocating manner in the pump case, and utilizes the pressure of hydraulic oil. In the water injection pump that pressurizes and discharges water to be discharged in the pump case by moving the plunger toward the discharge port side of the pump case, the pump case includes an outer peripheral surface of the plunger and an inner portion of the pump case. By moving the drainage drain part for discharging water flowing down the gap between the peripheral surface and the plunger after discharging the water to be discharged to the side opposite to the discharge port side of the pump case, An air spring that returns to a reference position before discharging water to be discharged, and the air spring includes an outer peripheral surface of the plunger and an inner peripheral surface of the pump case. The air chamber located below the said drainage drain portion a space surrounded by, characterized in that it is constituted by supplying a large pressure of the air than the internal pressure of the drainage drain unit.

  Further, in the water injection pump according to the present invention, in the above invention, the pump case includes a hydraulic oil drain part for discharging hydraulic oil remaining in the pump case below the air chamber, The air chamber is located between the upper drainage drain portion and the lower hydraulic oil drain portion.

  Further, the water injection pump according to the present invention is the water injection pump according to the above-mentioned invention, provided between the drainage drain part and the air chamber, and a gap between an outer peripheral surface of the plunger and an inner peripheral surface of the pump case, and the air chamber. A first seal member that closes communication with the air chamber, a lower internal space that is provided below the air chamber and that is located below the air chamber in the internal space of the pump case, and the air And a second seal member that closes communication with the chamber.

  According to the present invention, there is an effect that it is possible to provide a small and inexpensive water injection pump while avoiding corrosion and damage due to water of the compression spring for returning the plunger after discharging water to the reference position. .

FIG. 1 is a schematic cross-sectional view showing a configuration example of a water injection pump according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention. FIG. 3 is a view for explaining the action of the air spring in the embodiment of the present invention.

  Hereinafter, preferred embodiments of a water injection pump according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment. Also, the drawings are schematic, and it should be noted that the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual ones. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included. Moreover, in each drawing, the same code | symbol is attached | subjected to the same component.

(Composition of water injection pump)
FIG. 1 is a schematic cross-sectional view showing a configuration example of a water injection pump according to an embodiment of the present invention. In this embodiment, the case where this water injection pump 10 inject | pours water in the fuel flow path of a marine diesel engine (not shown) is illustrated. The fuel flow passage of the marine diesel engine is a fuel flow passage from the discharge port of the fuel injection pump to the injection port of the fuel injection valve through the pipe, although not particularly shown. A fuel injection pump is a device that injects fuel through piping or the like to a fuel injection valve for injecting fuel into a cylinder of a marine diesel engine.

  The water injection pump 10 is a hydraulically driven water injection pump that discharges water using the pressure of hydraulic oil. As shown in FIG. 1, the pump water pump 10 includes a pump case 1, a plunger 6, a pump case 1, and a plunger 6. Seal rings 7 and 8 for closing the gap, a detection unit 9 for detecting the movement amount (lift amount) of the plunger 6, and a water supply unit 17 for supplying water into the pump case 1 are provided. The pump case 1 includes a drainage drain part 11, a hydraulic oil drain part 12, an air spring 13 that applies a biasing force to the plunger 6, an air chamber 14, an air flow path 15a for constituting the air spring 13, and And an air inlet / outlet 15b.

  The pump case 1 is, for example, a pump case having a hollow cylindrical shape, and is configured by combining a plurality of cylindrical members having a hollow cylindrical shape. In the present embodiment, the pump case 1 includes a discharge part 2, a mounting base part 3, a support part 4, and a discharge valve part 5, as shown in FIG.

  As shown in FIG. 1, the discharge part 2 is a hollow cylindrical member having an internal space in which the water piston part 6a of the plunger 6 can be accommodated so as to be able to reciprocate. The discharge part 2 has the space part enclosed by the lower end part of the discharge valve part 5 and the upper end part of the water piston part 6a among this internal space as the discharge chamber 2a. The discharge chamber 2a is a space for temporarily storing water to be discharged. Although not shown in particular, the discharge part 2 is connected with the support part 4 by connection members, such as a volt | bolt.

  The mounting portion 3 is a case portion for attaching the water injection pump 10 to hydraulic oil supply equipment (not shown) such as a pressure accumulating portion that accumulates hydraulic oil pressure. As shown in FIG. 1, the mounting base 3 is formed in, for example, a hollow cylindrical shape, and has a hydraulic oil chamber 3 a that is an internal space for receiving hydraulic oil for operating the plunger 6. The hydraulic oil chamber 3a is formed so as to accommodate the hydraulic oil piston portion 6b of the plunger 6 so as to be able to reciprocate. Although not particularly illustrated, the mounting base 3 is connected to the support 4 by a connecting member such as a bolt.

  The support part 4 is a case part for supporting the plunger 6 and the detection part 9 provided in the pump case 1. As shown in FIG. 1, the support portion 4 is formed in, for example, a hollow cylindrical shape, and includes a middle portion of the plunger 6 (in this embodiment, the lower portion of the water piston portion 6 a, the regulating portion 6 c and the force receiving portion 6 d). It has an internal space that can be reciprocally accommodated. The support portion 4 has a space portion located between the upper seal ring 7 and the lower seal ring 8 as an air chamber 14 in the internal space, and is positioned below the air chamber 14. A space portion is provided as the lower internal space 4a. The support portion 4 supports the plunger 6 so as to be slidable in the axial direction F1 through the seal rings 7 and 8 so that the restriction portion 6c and the force receiving portion 6d of the plunger 6 face the air chamber 14. Moreover, the support part 4 supports the detection part 9 so that the detection terminal of the detection part 9 may be accommodated in the lower internal space 4a.

  As shown in FIG. 1, the discharge valve portion 5 is attached to the upper end portion of the discharge portion 2 by fitting or the like. For example, the discharge valve portion 5 is formed in a hollow cylindrical shape, and includes a check valve 5a that communicates with the discharge chamber 2a of the discharge portion 2 and a discharge port 5b that communicates with the outlet side of the check valve 5a. The discharge valve portion 5 is provided with a water injection pipe (not shown) that leads to the discharge port 5b. The check valve 5a regulates the direction of water discharge by the water injection pump 10 to a predetermined direction (in FIG. 1, the direction from the discharge chamber 2a side to the discharge port 5b side), and prevents backflow of this water. The discharge port 5b guides the water discharged from the discharge chamber 2a through the check valve 5a into the water injection pipe.

  The plunger 6 is for pressurizing and discharging water to be discharged using the pressure of the hydraulic oil. As shown in FIG. 1, the plunger 6 is a columnar member constituted by a water piston portion 6a, a hydraulic oil piston portion 6b, a restricting portion 6c, a force receiving portion 6d, and a tapered portion 6e. It is provided in the case 1 so as to be able to reciprocate.

  The water piston portion 6a is a portion for pressurizing and discharging water to be discharged. The water piston portion 6a is provided on one end side (upper side in FIG. 1) of the plunger 6 in the axial direction F1. As shown in FIG. 1, the water piston portion 6 a is accommodated in the internal space of the pump case 1 that continues from the discharge portion 2 to the support portion 4, and is supported by the support portion 4 via the seal ring 7. The water piston portion 6a reciprocates in the axial direction F1 of the plunger 6 while sliding on the seal ring 7. At this time, the water piston 6a moves in the direction of compressing the discharge chamber 2a and pressurizes the water in the discharge chamber 2a (that is, water to be discharged) to be discharged. In the present embodiment, the upper end surface of the water piston portion 6a is a pressure surface that pressurizes water to be discharged.

  The hydraulic oil piston portion 6 b is a portion for receiving the pressure of the hydraulic oil that operates the plunger 6. The hydraulic oil piston portion 6b is provided on the other end side (lower side in FIG. 1) of the plunger 6 in the axial direction F1. As shown in FIG. 1, the hydraulic oil piston portion 6 b is accommodated in the internal space (hydraulic oil chamber 3 a) of the mounting base portion 3 so as to reciprocate in the axial direction F <b> 1 of the plunger 6. The hydraulic oil piston portion 6b receives the pressure of the hydraulic oil supplied to the hydraulic oil chamber 3a, and moves (rises) from the reference position Ps to the one end side in the axial direction F1 of the plunger 6 by the pressure of the hydraulic oil. In the present embodiment, the lower end surface of the hydraulic oil piston portion 6b is a pressure receiving surface that receives the pressure of the hydraulic oil. The hydraulic oil piston portion 6b moves (lowers) to the other end side in the axial direction F1 of the plunger 6 while pushing the hydraulic oil in the hydraulic oil chamber 3a to the hydraulic oil supply facility side, and returns to the reference position Ps.

  The reference position Ps is the original position of the plunger 6 before the water injection pump 10 discharges water. The plunger 6 reciprocates in the axial direction F1 starting from the reference position Ps. In the present embodiment, the reference position Ps is determined by, for example, the height position of the lower end surface of the plunger 6 (that is, the lower end surface of the hydraulic oil piston portion 6b).

  The restricting portion 6c, the force receiving portion 6d, and the tapered portion 6e are provided between the water piston portion 6a and the hydraulic oil piston portion 6b along the axial direction F1 of the plunger 6. As shown in FIG. 1, the restricting portion 6c is formed at the lower end of the water piston portion 6a so as to have an outer diameter larger than that of the water piston portion 6a. When the plunger 6 moves to the discharge port 5b side (the upper side in the axial direction F1) of the pump case 1, the restricting portion 6c moves to the discharge port 5b side of the plunger 6 by contacting the inner wall surface of the air chamber 14. Regulate the range.

  As shown in FIG. 1, the force receiving portion 6d is formed at the lower end of the restricting portion 6c so as to have an outer diameter larger than that of the restricting portion 6c. In the present embodiment, the upper edge portion of the force receiving portion 6 d is a portion that receives the urging force of the air spring 13. The force receiving portion 6d moves toward the discharge port 5b against the biasing force of the air spring 13 when the plunger 6 moves toward the discharge port 5b of the pump case 1. Further, when the plunger 6 returns to the reference position Ps, the force receiving portion 6d receives the urging force of the air spring 13 and moves to the reference position Ps side.

  As shown in FIG. 1, the taper portion 6e is formed between the force receiving portion 6d and the hydraulic oil piston portion 6b so that the outer diameter decreases and changes from the upper side to the lower side in the axial direction F1 of the plunger 6. The The taper portion 6 e is used for detection of the lift amount of the plunger 6 by the detection unit 9.

  The plunger 6 having the configuration as described above moves to the discharge port 5b side of the pump case 1 by using the pressure of the hydraulic oil by receiving the pressure of the hydraulic oil by the hydraulic oil piston portion 6b. Thereby, the plunger 6 pressurizes so that the water in the discharge chamber 2a may be discharged by the water piston part 6a. Further, the plunger 6 receives the urging force of the air spring 13 by the force receiving portion 6d, and moves to the side opposite to the discharge port 5b side using this urging force. Thereby, the plunger 6 pushes out the hydraulic oil in the hydraulic oil chamber 3a by the hydraulic oil piston portion 6b and returns to the reference position Ps.

  The seal rings 7 and 8 are seal members for closing a gap between the inner peripheral surface of the pump case 1 and the outer peripheral surface of the plunger 6 (hereinafter abbreviated as a gap in the pump case as appropriate). As shown in FIG. 1, the seal ring 7 (first seal member) is fitted into a recess formed along the inner peripheral surface of the support portion 4 of the pump case 1, for example. It is provided between the waste water collection part 11a) and the air chamber 14. Here, the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1 is an intermediate peripheral surface of the plunger 6 and the inner peripheral surface of the support portion 4 of the pump case 1 in the internal space of the pump case 1. It is continuous with the air chamber 14 which is a space surrounded by. The seal ring 7 blocks communication between the gap 18 in the pump case 1 and the air chamber 14. Thus, the seal ring 7 hermetically separates the gap 18 and the air chamber 14 in the pump case 1 at a position between the drainage drain portion 11 and the air chamber 14.

  Further, as shown in FIG. 1, the seal ring 8 (second seal member) is inserted into a recess formed along the outer peripheral surface of the force receiving portion 6 d of the plunger 6, for example, than the air chamber 14. Provided on the lower side. Here, the lower side of the air chamber 14 is continuous with the lower inner space 4 a in the support portion 4 of the pump case 1. The seal ring 8 closes communication between the lower inner space 4a and the air chamber 14. As a result, the seal ring 8 hermetically separates the lower internal space 4a facing the hydraulic oil drain portion 12 and the air chamber 14 as shown in FIG.

  The detection unit 9 is a device for detecting the lift amount of the plunger 6 in one discharge of water by the water injection pump 10. As shown in FIG. 1, the detection portion 9 is supported by the support portion 4 of the pump case 1 so as to face the tapered portion 6 e of the plunger 6. In the present embodiment, the pair of detectors 9 are arranged in the lower inner space 4a of the pump case 1 so as to face each other in the radial direction F2 of the plunger 6 with the tapered portion 6e interposed therebetween. The detection unit 9 detects (measures) the distance from the taper portion 6 e that changes due to the movement (lift) of the plunger 6. The lift amount of the plunger 6 is calculated based on the detected distance and the inclination angle of the tapered portion 6e. The lift amount is an example of the movement amount of the plunger 6 that moves in the direction of pressurizing the water to be discharged (upward in this embodiment) in one water discharge by the water injection pump 10.

  The drainage drain part 11 is for discharging water flowing down the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1. As shown in FIG. 1, the drainage drain part 11 is constituted by a drainage collection part 11 a and a drainage channel 11 b, and is provided at a site above the air chamber 14 of the pump case 1. The drainage collecting part 11a is connected to the support part 4 of the pump case 1 (in this embodiment, the joint between the discharge part 2 and the support part 4) so as to communicate with the gap 18 between the outer peripheral face of the plunger 6 and the inner peripheral face of the pump case 1. Boundary portion). The drainage collecting part 11 a collects water flowing down the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1. The drainage channel 11b is provided in the support unit 4 so as to communicate the drainage collection unit 11a with the outside of the pump case 1. Although not particularly shown, a drain pipe is connected to the outlet of the drain channel 11b. The drainage drain part 11 collects the water in the discharge chamber 2a that is not discharged from the water injection pump 10 but leaks from the discharge chamber 2a in the pump case 1 into the gap 18 and flows down the gap 18 in the drainage collection part 11a. Then, the collected water is discharged from the inside of the pump case 1 to the external water distribution pipe through the drainage channel 11b.

  The hydraulic oil drain portion 12 is for discharging the hydraulic oil remaining in the pump case 1. As shown in FIG. 1, the hydraulic oil drain part 12 is constituted by a hydraulic oil collecting part 12 a and a hydraulic oil discharge path 12 b and is provided in a lower part than the air chamber 14 of the pump case 1. The hydraulic oil collecting part 12a is provided at a predetermined part of the pump case 1 (in the present embodiment, a boundary part between the support part 4 and the mounting part 3) so as to communicate with the lower internal space 4a of the pump case 1. . The hydraulic oil collecting part 12a collects the hydraulic oil leaked from the hydraulic oil chamber 3a along the outer peripheral surface of the hydraulic oil piston part 6b to the lower inner space 4a. The hydraulic oil discharge path 12b is provided in the pump case 1 (the mounting base 3 in the present embodiment) so as to allow communication between the hydraulic oil collecting unit 12a and the outside of the pump case 1. Although not particularly shown, a hydraulic oil discharge pipe is connected to the outlet of the hydraulic oil discharge passage 12b. The hydraulic oil drain part 12 collects the hydraulic oil remaining in the lower internal space 4a of the pump case 1 without being pushed out from the water injection pump 10 among the hydraulic oil in the hydraulic oil chamber 3a. The discharged hydraulic oil is discharged from the pump case 1 to the external hydraulic oil discharge pipe through the hydraulic oil discharge passage 12b. In the present embodiment, the used hydraulic oil discharged to the hydraulic oil discharge pipe is discarded without being reused.

  The air spring 13 is used to apply an urging force that urges the plunger 6 toward the reference position Ps. As shown in FIG. 1, the air spring 13 is constituted by air in an air chamber 14 formed in the pump case 1. The air chamber 14 is a space surrounded by the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1, and is located below the drainage drain part 11 (for example, below the drainage collection part 11 a). In the present embodiment, the air chamber 14 is located between the upper drainage drain part 11 and the lower hydraulic oil drain part 12. The upper side of the air chamber 14 is closed by the seal ring 7, and the lower side of the air chamber 14 is closed by the seal ring 8. The air spring 13 is configured by supplying air having a pressure larger than the internal pressure of the drainage drain portion 11 to the air chamber 14. For example, when the internal pressure of the drainage drain part 11 is atmospheric pressure, 0.5 MPa of air is supplied to the air chamber 14. Such an air spring 13 applies the urging force to the force receiving portion 6 d of the plunger 6. The air spring 13 is configured so that the plunger 6 after discharging water to be discharged (that is, the plunger 6 after moving in the direction in which the discharge chamber 2a is compressed) is applied to the force receiving portion 6d by the biasing force of the pump case 1. It is moved to the opposite side to the discharge port 5b side. Thereby, the air spring 13 returns this plunger 6 to the reference position Ps before discharging water to be discharged.

  The pump case 1 (the support portion 4 in the present embodiment) is provided with an air flow path 15a and an air inlet / outlet 15b for taking air into and out of the air chamber 14. As shown in FIG. 1, an air pipe 16 is connected to a portion of the pump case 1 where the air inlet / outlet 15 b is formed. The air flow path 15a communicates the air chamber 14 and the air pipe 16 via the air inlet / outlet 15b. The air inlet / outlet 15b is configured by an opening member having a small opening dimension such as an orifice. The air inlet / outlet 15b allows the air in and out of the air chamber 14 and the air pipe 16 through the air flow path 15a while maintaining the pressure of the air in the air chamber 14 (that is, the air pressure of the air spring 13) at a predetermined value or more. enable. In the present embodiment, the pressure of the air in the air chamber 14 is larger than the internal pressure of the gap 18 in the pump case 1 that leads to the drainage drain part 11 and the internal pressure of the lower internal space 4 a that leads to the hydraulic oil drain part 12. .

  The water supply part 17 is for supplying water into the discharge chamber 2a of the pump case 1, and is provided in the pump case 1 so as to communicate with the discharge chamber 2a. Water to be discharged is supplied from the water supply unit 17 to the discharge chamber 2a through a pipe of a water tank (not shown). The discharge chamber 2a is supplied (supplemented) with water to be discharged through the water supply unit 17 each time the water injection pump 10 discharges water.

(Operation of water injection pump)
FIG. 2 is a diagram for explaining the operation of the water injection pump according to the embodiment of the present invention. In this embodiment, the water injection pump 10 pressurizes and discharges water to be discharged in the pump case 1 by moving the plunger 6 to the discharge port 5b side of the pump case 1 using the pressure of the hydraulic oil. .

  Specifically, as shown in FIG. 2, the water injection pump 10 is in a state (state 1) in which the plunger 6 is positioned at the reference position Ps in a stage before discharging water. At this time, water to be discharged is supplied to the discharge chamber 2 a of the pump case 1 through the water supply unit 17. Thereby, the discharge chamber 2a is in a state filled with water to be discharged. The air chamber 14 is supplied with air having a pressure equal to or higher than a predetermined value from the air pipe 16 through the air inlet / outlet 15b and the air flow path 15a. Thus, an air spring 13 that urges the plunger 6 toward the reference position Ps is formed in the air chamber 14.

  Subsequently, when the water injection pump 10 discharges water, the hydraulic oil is supplied to the hydraulic oil chamber 3a of the pump case 1 through a control valve (not shown) of the hydraulic oil supply facility. The plunger 6 receives the pressure of the hydraulic oil in the hydraulic oil chamber 3a by the hydraulic oil piston portion 6b, and moves to the discharge port 5b side of the pump case 1 using the pressure of the hydraulic oil (the axial direction shown in FIG. 1). Rise to F1). At this time, the plunger 6 slides the outer peripheral surface of the water piston portion 6 a on the seal ring 7 on the inner peripheral surface of the pump case 1 and slides the seal ring 8 of the force receiving portion 6 d on the inner peripheral surface of the pump case 1. The air spring 13 moves against the urging force of the air spring 13 applied to the force receiving portion 6d. Thereby, the plunger 6 pressurizes water (water to be discharged) in the discharge chamber 2a with the water piston portion 6a (for example, pressurizes to about 15 MPa). The pressurized water to be discharged pushes the check valve 5a to flow to the discharge port 5b, and flows from the discharge port 5b into the fuel flow passage (not shown) of the marine diesel engine through the water injection pipe (not shown). Injected. Such water discharge by the water injection pump 10 is performed during the period when the hydraulic oil is supplied to the hydraulic oil chamber 3a, that is, the plunger 6 moves using the pressure of the hydraulic oil to add water in the discharge chamber 2a. Continued for the duration of pressure. By discharging this water, columnar fuel and columnar water are alternately present along the fuel flow path. As a result, it becomes possible to inject fuel and water into the cylinder of the marine diesel engine in layers.

  With the movement of the plunger 6 described above, the air spring 13 is pressed by the force receiving portion 6d. At this time, the high-pressure air constituting the air spring 13 flows out from the air chamber 14 to the air pipe 16 through the air flow path 15a and the air inlet / outlet 15b. The plunger 6 is moved from the reference position Ps to the lift position P1 (state 2). The movement amount (lift amount) of the plunger 6 is detected by the detection unit 9. Further, the movement of the plunger 6 is restricted by the contact between the restricting portion 6 c and the air chamber 14.

  Thereafter, when the supply of the hydraulic oil into the hydraulic oil chamber 3a is stopped, the water discharge by the water injection pump 10 is completed. At this time, air having a pressure equal to or higher than a predetermined value is supplied to the air chamber 14 again from the air pipe 16 through the air inlet / outlet 15b and the air flow path 15a. The air spring 13 constituted by the air supplied into the air chamber 14 applies a biasing force toward the reference position Ps to the force receiving portion 6d, thereby moving the plunger 6 toward the reference position Ps. The plunger 6 uses the urging force of the air spring 13 to transfer the hydraulic oil in the hydraulic oil chamber 3a (the hydraulic oil after being used for discharging the water) from the hydraulic oil chamber 3a to the outside of the pump case 1 (hydraulic oil). It moves toward the reference position Ps from the lift position P1 while pushing out to the supply equipment side). As a result, the plunger 6 releases the compression (water pressurization) of the discharge chamber 2a by the water piston portion 6a, and at the reference position Ps before the water is discharged as in state 1 shown in FIG. Return. The discharge chamber 2a is supplied with water to be discharged through the water supply unit 17, and thus the discharge chamber 2a returns to the state filled with the water to be discharged.

(Action of air spring)
FIG. 3 is a view for explaining the action of the air spring in the embodiment of the present invention. In the present embodiment, as described above, the air spring 13 applies a biasing force to the force receiving portion 6d of the plunger 6, thereby moving the plunger 6 to the side opposite to the discharge port 5b side of the pump case 1. To return to the reference position Ps. In addition to this action, the air spring 13 prevents water flowing down the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1 from the discharge chamber 2a from being mixed with the hydraulic oil in the pump case 1. .

  Specifically, as shown in FIG. 3, an air spring 13 is configured in the air chamber 14 by supplying air having a pressure equal to or higher than a predetermined value. The air pressure of the air spring 13 is larger than the internal pressure of the drainage drain part 11. That is, the air pressure of the air spring 13 is larger than the internal pressure of the gap 18 in the pump case 1 that communicates with the drainage collecting part 11a and the drainage channel 11b of the drainage drain part 11. The air pressure of the air spring 13 is larger than the internal pressure of the hydraulic oil drain part 12. That is, the air pressure of the air spring 13 is larger than the internal pressure of the lower internal space 4a in the pump case 1 that communicates with the hydraulic oil collecting portion 12a and the hydraulic oil discharge passage 12b of the hydraulic oil drain portion 12.

  As shown in FIG. 3, the upper side of the air chamber 14 is closed by the seal ring 7, and the lower side of the air chamber 14 is closed by the seal ring 8. The upper seal ring 7 separates the gap 18 in the pump case 1 and the air chamber 14 in a liquid-tight (preferably air-tight) manner at a position below the drainage drain portion 11. The lower seal ring 8 separates the lower inner space 4a of the pump case 1 and the air chamber 14 in a liquid-tight (preferably air-tight) manner at a position above the hydraulic oil drain portion 12.

  Here, in the pump case 1, a part of the water to be discharged supplied into the discharge chamber 2 a (see FIG. 1) is not discharged from the discharge chamber 2 a and the inside of the pump case 1. There is a case where the air leaks into the gap 18 with the peripheral surface. The water 19 leaking into the gap 18 in the pump case 1 flows down through the gap 18 toward the air chamber 14 as shown in FIG. The flow of water 19 in the gap 18 is normally blocked by the action of the upper seal ring 7. As a result, the water 19 in the gap 18 flows into the drainage collecting portion 11a without entering the air chamber 14, and is discharged outside the pump case 1 through the drainage channel 11b. That is, in the pump case 1, the water 19 in the gap 18 does not pass through the air chamber 14 and does not flow into the lower internal space 4 a. Therefore, if the water 19 in the gap 18 does not come into contact with the detection unit 9 facing the lower inner space 4a, it mixes with the hydraulic oil in the hydraulic oil drain unit 12 or the hydraulic oil in the hydraulic oil chamber 3a. There is nothing.

  If the upper seal ring 7 is worn or damaged by sliding of the plunger 6 or the like, the upper seal ring 7 may not be able to block the water 19 flowing down the gap 18 in the pump case 1. Even in such a case, the air spring 13 can block the flow of the water 19 in the gap 18 by the air pressure, and can push the water 19 from the gap 18 toward the drainage collecting part 11a. In this way, the air spring 13 prevents the water 19 in the gap 18 from passing through the air chamber 14 and flowing into the lower internal space 4a. As a result, it is possible to prevent the detection unit 9 from coming into contact with the water 19 and fail, and to prevent the water 19 from being mixed into the hydraulic oil in the pump case 1. Even when the lower seal ring 8 is damaged by the sliding of the plunger 6 or the like, the air spring 13 prevents the hydraulic oil from entering the air chamber 14 from the lower inner space 4a by the air pressure. be able to. Also in this case, the air spring 13 can prevent the hydraulic oil in the pump case 1 and the water 19 from being mixed.

  As described above, in the water injection pump 10 according to the embodiment of the present invention, the water 19 flowing down the gap 18 between the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1 in the pump case 1 is discharged. The air chamber 14 surrounded by the outer peripheral surface of the plunger 6 and the inner peripheral surface of the pump case 1 is formed at a position lower than the drainage drain portion 11 to be operated, and the internal pressure of the drainage drain portion 11 is formed in the air chamber 14. The air spring 13 is configured by supplying air of a higher pressure, and the plunger 6 after discharging the water to be discharged is moved to the reference position Ps before discharging the water to be discharged by the biasing force of the air spring 13. To return to.

  For this reason, even if it does not use compression springs, such as a coil spring, the water injection pump which can return the plunger moved to the discharge outlet side to discharge water to the standard position before movement can be constituted simply. . As a result, it is not necessary to take measures against corrosion and damage to the compression springs conventionally used to return the plunger after discharging water to the reference position, and a small and inexpensive water injection pump can be provided.

  Further, the air spring 13 is constituted by air having a pressure larger than the internal pressure of the drainage drain part 11. For this reason, even if the seal ring 7 provided on the upper side of the air chamber 14 is damaged, the water 19 flowing down the gap 18 in the pump case 1 leading to the drainage drain portion 11 is supplied to the air pressure of the air spring 13. Can be blocked by. Thereby, it is possible to prevent the water 19 in the gap 18 from passing through the air chamber 14 and flowing into the lower internal space 4a of the pump case 1. As a result, it is possible to prevent a situation in which equipment such as the detection unit 9 facing the lower internal space 4a comes into contact with the water 19 and break down, and to prevent a situation in which the water 19 is mixed into the hydraulic oil in the pump case 1. Can do.

  Moreover, in the water injection pump 10 which concerns on embodiment of this invention, the hydraulic oil drain part for discharging | emitting the hydraulic oil which remains in the pump case 1 in the position below the air chamber 14 in the pump case 1 12 is provided so that the air chamber 14 is located between the upper drainage drain portion 11 and the lower hydraulic oil drain portion 12. For this reason, it is possible to prevent the water 19 flowing down the gap 18 in the pump case 1 from passing through the air chamber 14 and entering the hydraulic oil drain portion 12 by the air pressure of the air spring 13. Thereby, even if the seal rings 7 and 8 provided above and below the air chamber 14 are damaged, it is possible to prevent the water 19 from being mixed into the hydraulic oil in the hydraulic oil drain portion 12.

  In addition, in the water injection pump 10 according to the embodiment of the present invention, the seal ring 7 that closes the communication between the gap 18 in the pump case 1 and the air chamber 14 is provided between the drainage drain portion 11 and the air chamber 14. A seal ring 8 that closes communication between the lower inner space 4 a of the pump case 1 and the air chamber 14 is provided below the air chamber 14. For this reason, the gap 18 and the air chamber 14 in the pump case 1 can be separated in a liquid-tight (preferably air-tight) manner by the upper seal ring 7 at a position below the drainage drain part 11, and the hydraulic oil drain The lower inner space 4a and the air chamber 14 of the pump case 1 can be separated in a liquid-tight (preferably air-tight) manner by the lower seal ring 8 at a position above the portion 12. As a result, the air spring 13 having an air pressure of a predetermined value or more can be easily configured in the air chamber 14.

  In the above-described embodiment, the seal rings 7 and 8 are provided above and below the air chamber 14, but the present invention is not limited to this. For example, the water 19 flowing down the gap 18 in the pump case 1 may be blocked by the air pressure of the air spring 13 without using the seal rings 7 and 8.

  In the above-described embodiment, the case where the used hydraulic oil discharged from the hydraulic oil drain portion 12 to the hydraulic oil discharge pipe is discarded without being reused is exemplified. However, the present invention is limited to this. Is not to be done. For example, the used hydraulic oil discharged from the hydraulic oil drain unit 12 to the hydraulic oil discharge pipe may be reused as hydraulic oil that is collected in a tank or the like to operate hydraulically driven equipment such as the water injection pump 10. Good.

  Further, the present invention is not limited by the above-described embodiment, and the present invention includes a configuration in which the above-described constituent elements are appropriately combined. In addition, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Pump case 2 Discharge part 2a Discharge chamber 3 Mounting base part 3a Hydraulic oil chamber 4 Support part 4a Lower internal space 5 Discharge valve part 5a Check valve 5b Discharge port 6 Plunger 6a Water piston part 6b Hydraulic oil piston part 6c Control part 6d Force receiving portion 6e Taper portion 7, 8 Seal ring 9 Detection portion 10 Water injection pump 11 Drain drain portion 11a Drain collection portion 11b Drain passage 12 Hydraulic oil drain portion 12a Hydraulic oil collection portion 12b Hydraulic oil discharge passage 13 Air spring 14 Air chamber 15a Air flow path 15b Air inlet / outlet 16 Air piping 17 Water supply part 18 Clearance 19 Water F1 Axial direction F2 Radial direction P1 Lift position Ps Reference position

Claims (3)

A pump case and a plunger provided in the pump case so as to be capable of reciprocating, and by moving the plunger toward the discharge port side of the pump case by using the pressure of hydraulic oil, a discharge target in the pump case In a water injection pump that pressurizes and discharges water,
The pump case is
A drainage drain portion for discharging water flowing down the gap between the outer peripheral surface of the plunger and the inner peripheral surface of the pump case;
An air spring that returns the reference position before discharging the water to be discharged by moving the plunger after discharging the water to be discharged to the side opposite to the discharge port side of the pump case;
With
The air spring is a space surrounded by the outer peripheral surface of the plunger and the inner peripheral surface of the pump case, and is located below the drainage drain part, and has an air pressure higher than the internal pressure of the drainage drain part. A water injection pump configured to supply air of high pressure. The pump case includes a hydraulic oil drain portion for discharging hydraulic oil remaining in the pump case below the air chamber.
The water injection pump according to claim 1, wherein the air chamber is located between the upper drainage drain portion and the lower hydraulic oil drain portion. A first seal member provided between the drainage drain portion and the air chamber, and closing a communication between the air chamber and a gap between an outer peripheral surface of the plunger and an inner peripheral surface of the pump case;
A second seal member provided below the air chamber and blocking communication between the air chamber and a lower inner space located below the air chamber in the inner space of the pump case; ,
The water injection pump according to claim 1, further comprising:

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