JP2019210878A - Piston pump device - Google Patents

Abstract

To provide a piston pump device capable of significantly suppressing discharge of a compressed body to the external even under large temperature drop and the like.SOLUTION: An intermediate portion (50) is disposed to tightly cover a projection port of a piston rod disposed between a piston pump main body and an actuator (60), and disposed on a basic portion-side end portion of the piston pump main body from an outer side, and gas supply mechanisms (71, 72, 74, 75) are disposed to supply a gas into the intermediate portion to increase an air pressure in the intermediate portion. Further exhaust gas adjustment mechanisms (74, 75, 80, 81) are disposed to adjust an exhaust condition amount of a gas exhausted from an exhaust passage (44) of the gas supplied to pressurize a seal portion (30) of the piston pump main body. Further a second seal portion (52) is disposed at a basic portion side of the intermediate portion to densify the intermediate portion and a rod portion (61).SELECTED DRAWING: Figure 4

Description

  The present invention is suitable for use when, for example, a cryogenic liquid having a very low boiling point such as liquefied natural gas is sucked into a cylinder liner by a piston, and is discharged at a high pressure by this piston and supplied to a supply object. The present invention relates to a piston pump device.

  Conventionally, diesel engines using liquefied natural gas as fuel have been used in vehicles and the like. However, in recent years, in low-speed diesel engines using heavy oil-based fuels, high-pressure natural gas is injected into the engine cylinders and burned in order to improve emissions environment performance by reducing emissions such as NOx and SOX. Development of a high-pressure gas injection type low-speed two-cycle diesel engine is underway. The high-pressure gas injection type low-speed two-cycle diesel engine is a relatively large diesel engine, and is generally used for ships and the like.

  On the other hand, in ships and the like, it is necessary to be able to arrange a liquefied gas supply device in a gas hazardous area, and therefore, development of a liquefied gas supply device excellent in safety is being promoted (for example, Patent Document 1). reference). In this liquefied gas supply device, a piston pump device is used as a boosting device for boosting and discharging low-temperature liquefied natural gas to a desired pressure and supplying the heated high-pressure liquefied natural gas to a heating device that vaporizes the gas. used.

  The piston pump body of this conventional piston pump device has the following configuration as shown in FIG. 7 (see, for example, Patent Document 1). The cylinder liner 103 in the cylinder 102 of the piston pump 101, the cylinder head chamber 104, the piston 105 inserted into the cylinder liner 103, the valve head 106 disposed in the cylinder head chamber 104, and the cylinder head 107 attached to the cylinder 102. Is disposed.

  The cylinder head chamber 104 is provided in the cylinder 102 between the cylinder liner 103 and the cylinder head 107. The piston 105 reciprocates in the cylinder liner 103 through a piston rod 112 or the like attached to the base of the piston 105 using an actuator or the like controlled by a controller (not shown) as a drive source. The cylinder 102 has a liquid fuel supply port 108, and low-temperature liquid fuel is guided into the cylinder head chamber 104 through the supply port 108 at a relatively low pressure.

  The liquid fuel pressurized from the piston 105 is discharged to the outside at a high pressure through the discharge port 109. A discharge passage 110 communicating with the discharge port 109 is formed in the cylinder head 107 in the axial direction. The cylinder liner 103 has a valve storage chamber 113 on the valve head 106 side, and the valve storage chamber 113 includes a valve plate (not shown) and a suction spring (not shown) that biases the valve plate toward the valve head 106 side. A valve is provided. The piston 105 has a plurality of piston ring grooves 118 formed on the outer periphery thereof, and a piston ring 119 is attached to each piston ring groove 118.

Further, the liquid fuel leaking from between the cylinder 102 and the cylinder liner 103 is returned to the liquid fuel supply side via the discharge ports 128 and 129, respectively. Further, the piston rod 112 described above is liquid-tight and air-tight with the cylinder 102 by a seal portion 121 made up of a plurality of rod packings disposed in the cylinder 102, and is connected via the discharge port 129 and the like. Thus, the liquid fuel on the supply side communicating therewith is prevented from leaking from between the cylinder 102 and the piston rod 112 to the outside. Further, nitrogen gas is supplied to the seal portion 121 from the outside and pressurized, so that the liquid fuel does not leak to the outside from between the cylinder 102 and the piston rod 112.

  The above-described seal portion 121 is configured by arranging a plurality of rod packings interposed between the cylinder 102 and the piston rod 112 in the axial direction. Each rod packing is formed of three tangentially divided ring segments or three spiral ring segments, and the rod packings are assembled in layers, for example, two in the axial direction. Thus, the above-described packing portions are formed.

Japanese Patent No. 5934409

  As described above, the seal portion 121 of the conventional piston pump body is composed of a plurality of rod packings, and each rod packing is composed of three tangential split ring segments or three spiral ring segments. These rod packings are assembled in layers, for example, two in the axial direction to form the above-described packing portions. Further, as described above, nitrogen gas is supplied from the outside to the seal portion 121 and pressurized, so that liquid fuel does not leak from between the cylinder 102 and the piston rod 112 to the outside.

  On the other hand, for example, in the case of a piston pump device used for pressurizing a cryogenic liquid, for example, a fluororesin composite material is often used as the material of the rod packing described above. This fluororesin composite material has a thermal expansion coefficient of about 10 times that of a metal material, is easily affected by temperature changes, and has extremely high rigidity under extremely low temperature conditions and is difficult to deform.

  For this reason, in the piston pump device for pressurizing the cryogenic liquid, each ring segment forming the rod packing contracts greatly due to a temperature drop accompanying operation, and the shape does not conform to the outer shape of the piston rod 112. It becomes extremely hard and difficult to deform.

  For this reason, each ring segment of the rod packing does not follow the outer peripheral portion of the piston rod 112 at an extremely low temperature, and liquid fuel (vaporized gas is included between the rod packing constituting the seal portion 121 and the piston rod 112. ) Leaks out of the discharge port on the base side of the piston rod 112 to the outside.

  On the other hand, since a special seal mechanism is not conventionally provided between the junction box connecting the piston pump body and the actuator and the actuator rod, the density is relatively low. For this reason, when the leakage of the liquid fuel from the discharge port on the base side of the piston rod 112 increases, the liquid fuel leaks from the gap between the junction box and the actuator rod and is released into the atmosphere as it is.

  On the other hand, a part of the liquid fuel leaking from between the rod packing and the piston rod 112 is released into the atmosphere as it is with the nitrogen gas that has been preloaded. However, if the amount of leakage of liquid fuel increases due to deformation or hardening of the rod packing due to temperature drop or the like, the amount of liquid fuel released into the atmosphere also increases. Further, in order to reduce the leakage amount of the liquid fuel from the rod packing to increase the pressure of the supplied nitrogen gas and cope with this, there arises a problem that a large amount of nitrogen gas is consumed.

  The present invention has been made to solve such problems, and it is intended to provide a piston pump device capable of significantly suppressing discharge of a fluid to be compressed to the outside even when there is a large temperature drop or the like. Let it be an issue.

  In order to solve the above-described problems, a piston pump device according to the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress a fluid to be compressed, and is coupled to the piston. And a piston rod that is inserted into the cylinder to reciprocate the piston in the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder to tightly seal between the piston rod and the cylinder. A pump body, an actuator rod connected to the piston rod of the piston pump body, and an actuator for reciprocating the piston in the cylinder via the piston rod, and a piston pump body disposed between the piston pump body and the actuator Remove the piston rod protrusion provided at the base end of the An intermediate portion tightly covered from lies in that a gas supply mechanism to increase the pressure in the intermediate portion by supplying gas to the intermediate portion. Here, the above-mentioned base side refers to the actuator side, and the below-mentioned tip side refers to the piston side of the piston pump body. The term “tight” refers to, for example, liquid tightness or air tightness. The same applies hereinafter.

  Thus, an intermediate portion is provided between the piston pump main body and the actuator, and is provided at the end of the piston pump main body on the base side to cover the projecting port of the piston rod and the rod portion from the outside. By providing a gas supply mechanism that supplies gas into the intermediate part to increase the atmospheric pressure in the intermediate part, the inside of the intermediate part is preloaded and leaks from the protruding port of the piston rod provided at the end on the base side of the piston pump body. The amount of leakage of the fluid to be compressed can be greatly reduced. Thereby, even if there is a large temperature drop or the like, it is possible to greatly suppress the release of the compressed fluid leaked from between the piston rod of the piston pump body and the cylinder to the atmosphere.

  In the above piston pump device, the gas supply mechanism includes a gas supply source that supplies gas, a pressure adjustment unit that adjusts the pressure of the gas supplied from the gas supply source, and supplies the pressure to the intermediate part, and a piston pump for the fluid to be compressed A pressure detection unit that detects supply pressure to the main body, and a controller that operates the pressure adjustment unit based on the supply pressure of the fluid to be compressed detected by the pressure detection unit to adjust the pressure of the gas supplied to the intermediate unit. It is desirable to provide.

  The pressure of the gas supplied for preload into the intermediate part is optimally adjusted according to the supply pressure of the fluid to be compressed to the piston pump body. As described above, the controller operates the pressure adjustment unit based on the supply pressure of the fluid to be compressed detected by the pressure detection unit, and adjusts the pressure of the gas supplied for preload into the intermediate unit, An optimal preload according to the supply pressure of the fluid to be compressed can be performed on the intermediate portion.

  In the above piston pump device, the controller desirably adjusts the pressure of the gas supplied to the intermediate portion to be higher than the supply pressure of the fluid to be compressed.

  From various verification experiments by the inventor, by increasing the pressure of the gas supplied for preload into the intermediate part higher than the supply pressure of the fluid to be compressed, the piston rod cylinder protruding from the piston pump body to the base side It has been found that the amount of compressed fluid leaking from the projecting port can be greatly reduced. Thereby, even if there is a large temperature drop or the like, it is possible to further greatly suppress the release of the compressed fluid leaking from between the piston rod and the cylinder of the piston pump body into the atmosphere.

Alternatively, in order to solve the above-described problem, a piston pump device of the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress a fluid to be compressed, and a piston. Connected and inserted into the cylinder to reciprocate the piston in the cylinder liner, and arranged between the piston rod and the cylinder to close the space between the piston rod and the cylinder and supply from the outside A piston pump body having a seal portion that is preloaded by the generated gas, an exhaust passage for exhausting the gas supplied to the seal portion of the piston pump body for pressurization, and the exhaust passage. And an exhaust adjustment mechanism for adjusting the exhaust state quantity of the gas exhausted from the exhaust passage.

  Thus, the piston pump is disposed between the piston rod and the cylinder so as to close the space between the piston rod and the cylinder and has a seal portion that is preloaded by the gas supplied from the outside. An exhaust passage for exhausting the gas supplied to the seal portion of the main body for pressurization to the outside, and an exhaust adjustment mechanism for adjusting the exhaust state amount of the gas exhausted from the exhaust passage disposed in the exhaust passage. By providing, the back pressure of the seal portion is optimally adjusted, and the leakage amount of the fluid to be compressed leaking from the seal portion to the outside can be greatly reduced.

  As a result, even if there is a large temperature drop, etc., the compressed fluid that passes through the seal part and leaks to the outside from the base side of the piston rod or into the gas for pressurization of the seal part and leaks from the exhaust passage. The release into the atmosphere can be greatly suppressed. Moreover, mass consumption of the pressurized gas can be suppressed.

  Furthermore, the seal part is generally constituted by a packing part in which a plurality of parts are arranged in the axial direction of the piston rod. In this case, each of the supply pressures of liquid fuel received by each packing part is It is extremely important to minimize the pressure difference acting on the packing portion in order to ensure the tightness and durability of the entire seal portion.

  According to the piston pump device of the present invention, by providing the discharge adjustment mechanism for adjusting the exhaust state quantity of the gas exhausted from the exhaust passage as described above, each packing of the supply pressure of the liquid fuel received by each packing portion is provided. The pressure difference acting on the portions can be reduced, respectively, and thereby the tightness and durability of the entire seal portion can be greatly improved.

  In the piston pump device, the exhaust adjustment mechanism includes an exhaust adjustment unit that adjusts an exhaust state quantity, a pressure detection unit that detects a supply pressure of the compressed fluid to the piston pump body, and a compressed fluid that is detected by the pressure detection unit. It is desirable to provide a controller that operates the exhaust adjustment unit based on the supply pressure.

  It is desirable that an exhaust state quantity such as an exhaust flow rate and an exhaust pressure of the pressurizing gas exhausted from the seal portion is adjusted according to a supply pressure of the fluid to be compressed to the piston pump body. As described above, the controller operates the exhaust adjustment unit based on the supply pressure of the fluid to be compressed detected by the pressure detection unit, thereby optimally adjusting the exhaust state quantity of the pressurized gas exhausted from the seal unit. be able to.

  In the piston pump device, the exhaust state amount is an exhaust flow rate of the gas, and the exhaust adjustment unit includes a flow control valve capable of adjusting the exhaust flow rate, and the flow control valve exhausts from the exhaust path to the outside. It is desirable to adjust the exhaust gas flow rate to be a predetermined amount. The exhaust state quantity is the exhaust pressure of the gas, and the exhaust adjustment unit includes a pressure control valve capable of adjusting the exhaust pressure, and the pressure control valve allows the exhaust gas to be exhausted to the outside from the exhaust path. It is desirable to adjust the exhaust pressure so that it becomes a predetermined pressure.

As described above, the exhaust adjustment unit is constituted by the flow rate control valve, the exhaust adjustment unit is constituted by the pressure control valve, or the exhaust adjustment unit is constituted by the flow rate control valve and the pressure control valve. The amount and / or the exhaust pressure can be adjusted optimally, whereby the preload of the seal portion is optimized, and the amount of leakage of the fluid to be compressed can be greatly reduced.

  In the piston pump device, it is preferable that the controller adjusts the exhaust adjustment mechanism so that the exhaust pressure of the gas is lower than the supply pressure of the fluid to be compressed.

  From various verification experiments by the inventor, the above-mentioned exhaust state quantity leaks from the seal portion of the piston pump body by adjusting the exhaust pressure of the preload gas in the seal portion to be lower than the supply pressure of the fluid to be compressed. It has been found that the leakage amount of the compressed fluid to be discharged can be greatly reduced. Thereby, even if there exists a big temperature fall etc., discharge | release to the exterior of a to-be-compressed fluid can be suppressed further reliably.

  Alternatively, in order to solve the above-described problem, a piston pump device of the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress a fluid to be compressed, and a piston. A piston rod that is connected and inserted into the cylinder to reciprocate the piston in the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder to close the space between the piston rod and the cylinder. A piston pump body having an actuator rod connected to the piston rod of the piston pump body and reciprocating the piston in the cylinder via the piston rod; and a piston rod or actuator protruding from the piston pump body to the base side From the actuator rod protruding to the tip side A rod portion disposed between the piston pump main body and the actuator and provided at the end of the piston pump main body on the base side, and an intermediate portion that covers the rod portion from the outside, There is provided a second seal portion disposed between the intermediate portion and the rod portion and on the base side of the intermediate portion to close the space between the intermediate portion and the rod portion.

  In this way, an intermediate portion is provided between the piston pump main body and the actuator, and covers the piston rod projecting port and the rod portion tightly from the outside provided at the end of the piston pump main body on the base side. It is compared with the related art by further including a second seal portion disposed between the intermediate portion and the rod portion and on the base side of the intermediate portion to close the space between the intermediate portion and the rod portion. It is possible to further increase the density on the base side of the intermediate portion, which has been considered to be low in density, and to increase the density of the entire intermediate portion. Therefore, even if there is a large temperature drop or the like, it is possible to greatly suppress the discharge of the compressed fluid leaking from between the piston rod and the cylinder of the piston pump body into the atmosphere.

  In the piston pump device, the second seal portion includes a seal ring made of a material having self-lubricating property, and a pressing member that presses the seal ring against the rod portion to close the space between the seal ring and the rod portion. It is desirable to provide.

  The seal ring made of a self-lubricating material has a relatively simple structure but provides sufficient slidability between the seal ring and the rod part even when it is oil-free. A very high density can be given between the two. Thereby, discharge | release to the atmosphere of the to-be-compressed fluid which leaked from between the piston rod and cylinder of a piston pump main body can further be prevented. In particular, since the seal ring is made of a self-lubricating material, it is not necessary to provide a special oil supply mechanism for the second seal portion. For this reason, it is inexpensive and easy to maintain.

As described above, the piston pump device according to the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress the fluid to be compressed, and is coupled to the piston and within the cylinder. A piston pump main body having a piston rod that is inserted into the cylinder liner and reciprocatingly moves the piston in the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder to tightly seal between the piston rod and the cylinder; An actuator rod is connected to the piston rod of the piston pump main body, and the piston is reciprocated in the cylinder via the piston rod, and is disposed between the piston pump main body and the actuator and is connected to the base end of the piston pump main body. An intermediate portion that covers the protruding opening of the piston rod provided in the portion from the outside; And a gas supply mechanism to increase the pressure in the intermediate portion by supplying gas to the intermediate portion.

  Alternatively, the piston pump device of the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress the fluid to be compressed, and is connected to the piston and inserted into the cylinder. A piston rod that reciprocates the piston in the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder so as to close the space between the piston rod and the cylinder and is preloaded by the gas supplied from the outside. A piston pump main body, an exhaust passage for exhausting gas supplied to the seal portion of the piston pump main body to the outside, and a gas disposed in the exhaust passage and exhausted from the exhaust passage. An exhaust adjustment mechanism for adjusting the exhaust state quantity.

  Alternatively, the piston pump device of the present invention includes a cylinder having a cylinder liner therein, a piston that is reciprocally inserted into the cylinder liner to compress the fluid to be compressed, and is connected to the piston and inserted into the cylinder. A piston pump main body having a piston rod for reciprocating the piston in the cylinder liner, and a seal portion disposed between the piston rod and the cylinder to tightly seal between the piston rod and the cylinder, and an actuator rod thereof Is connected to the piston rod of the piston pump body, and the piston is reciprocated in the cylinder via the piston rod, and the piston rod protruding from the piston pump body to the base side or the actuator rod protruding from the actuator to the tip side Rod part and piston An intermediate portion that is disposed between the main body and the actuator and that is provided at the end of the piston pump main body on the base side and covers the rod portion from the outside, and an intermediate portion between the intermediate portion and the rod portion. And a second seal portion disposed on the base side of the intermediate portion to close the space between the intermediate portion and the rod portion.

  Therefore, this piston pump device has an excellent effect that the discharge of the fluid to be compressed to the outside can be significantly suppressed even when there is a large temperature drop or the like.

It is an axial direction sectional view showing the piston pump main part of the piston pump device concerning the present invention. It is an axial sectional view showing a part of a piston pump main body, an intermediate part, and an actuator of a piston pump device according to the present invention. It is an axial sectional view which shows the seal part of the piston pump main body of FIG. FIG. 2 is a simplified diagram showing the piston pump device of FIG. 1. FIG. 5 is an axial sectional view showing a seal ring of the piston pump device of FIG. 4. FIG. 5 is a simplified diagram showing a piston pump device different from FIG. 4. It is an axial sectional view showing a piston pump body of a conventional piston pump device.

  An embodiment for implementing a piston pump according to the present invention will be described in detail with reference to FIGS. 1 to 6. FIG. 1 shows a piston pump main body 1 which is one of the components of the piston pump device of the present invention. FIG. 2 shows a part of the piston pump main body 1 of the piston pump device of the present invention and other components. A certain junction box (intermediate part) 50 and actuator 60 are shown.

  The piston pump device shown in FIGS. 1 and 2 is used for, for example, ships, and is used for a liquefied gas supply device of a high-pressure gas injection type low-speed two-cycle diesel engine that injects and burns high-pressure liquefied natural gas. Is done. Then, the supplied cryogenic liquid fuel (compressed fluid) is discharged to a desired pressure, and supplied to a heating device for heating and vaporizing the liquid fuel.

  As shown in FIG. 2, the present piston pump device is connected to the piston pump body 1 shown in FIG. 1 and the base side of the piston rod (rod portion) 12 of the piston pump body 1. A hydraulically driven actuator 60 having an actuator rod (rod portion) 61 for reciprocating in the cylinder liner 3 and a piston pump main body 1 and the actuator 60 are disposed between the piston pump main body 1 and the base side. The piston rod 12 projecting from the actuator 60 and the actuator rod 61 projecting from the actuator 60 toward the tip end side are formed from a junction box 50 that covers the connection portion from the outside in a liquid-tight and air-tight manner.

  The connection box 50 supports the piston pump body 1 and the actuator 60 coaxially. The piston rod 12 of the piston pump main body 1 and the actuator rod 61 of the actuator 60 are coupled within the connection box 50 and interlocked together.

  The liquid fuel pressurized by the piston 5 may leak from the projecting port 47 of the piston pump body 1 of the piston rod 12 projecting from the piston pump body 1 to the base side. The connection box 50 covers the projecting port 47 and the piston rod 12 from the outside in a liquid-tight and air-tight manner so that the liquid fuel leaking from the projecting port 47 is prevented from being discharged to the outside, that is, into the atmosphere as much as possible.

  As shown in FIG. 1, a piston pump body 1 includes a cylinder 2 having a cylinder liner 3 therein, a piston 5 inserted in the cylinder liner 3 so as to be capable of reciprocating in a liquid-tight and air-tight manner, and a tip of the cylinder 2. A cylinder head 7 which is liquid-tight and air-tightly attached to the part, a cylinder head chamber 4 which is a cavity defined between the cylinder liner 3 and the cylinder head 7 in the cylinder 2, and the cylinder head chamber 4. The valve head 6 is provided, and a plurality of suction passages 17 which are formed in the valve head 6 and communicate with the cylinder head chamber 4 and the cylinder liner 3 are disposed. The suction passages 17 are arranged at substantially equal intervals in the circumferential direction of the valve head 6.

  The cylinder head chamber 4 is provided in the cylinder 2 between the cylinder liner 3 and the cylinder head 7 so as to communicate over 360 ° in the circumferential direction. The piston 5 reciprocates in the cylinder liner 3 by the actuator 60 described above. The cylinder 2 has a liquid fuel supply port 8, and cryogenic liquid fuel is supplied into the cylinder head chamber 4 through the supply port 8 at a relatively low pressure.

The liquid fuel pressurized by the piston 5 is discharged outside at high pressure through the discharge port 9 of the cylinder head 7. A discharge passage 10 communicating with the discharge port 9 is formed in the cylinder head 7 in the axial direction. The cylinder liner 3 has a valve housing chamber 13 on the valve head 6 side. The valve housing chamber 13 includes a valve plate (not shown) and a pressure spring (not shown) for urging the valve plate toward the valve head 6. An intake valve is provided.

  The piston 5 has a plurality of piston ring grooves 18 formed on the outer periphery thereof, and a piston ring 19 is attached to each piston ring groove 18. Further, the tip of the piston 5 has a protrusion 16 that is formed with a smaller diameter than the piston 5 and protrudes toward the valve head 6. On the other hand, the liquid fuel leaking from between the cylinder 2 and the cylinder liner 3 is returned to the liquid fuel supply side via the discharge ports 28 and 29, respectively.

  The above-described piston rod 12 is liquid-tight and air-tight with the cylinder 2 by a seal portion 30 disposed in the cylinder 2, and is connected to the supply-side liquid fuel via, for example, the above-described discharge port 29. Is prevented from leaking from between the cylinder 2 and the piston rod 12 to the outside. The seal portion 30 is urged toward the base side by the coil spring 32 via the retainer 31 and is fixed in the cylinder 2.

  Further, nitrogen gas is supplied to the seal portion 30 from the outside through a nitrogen gas supply passage 43 formed in the cylinder 2 and is pressurized, so that liquid fuel is also supplied from between the cylinder 2 and the piston rod 12 to the outside. I try not to leak. A part of the liquid fuel leaking from the seal portion 30 is diluted with this pressurizing nitrogen gas and then exhausted from the piston pump main body 1 together with the nitrogen gas into the atmosphere through a nitrogen gas exhaust passage 44 described later. That is, since the discharged liquid fuel is diluted with nitrogen gas, explosion in the atmosphere is prevented.

  In the piston pump main body 1, the suction valve in the valve housing chamber 13 opens the outlet of the suction passage 17 during the suction stroke of the piston 5 and closes the outlet of the suction passage 17 during the compression stroke of the piston 5. The discharge valve 11 closes the discharge path 10 provided in the cylinder head 7 during the intake stroke of the piston 5 and opens the discharge path 10 during the compression stroke of the piston 5.

  The valve head 6 is provided with an outlet opening 21 communicating from the end surface on the cylinder liner 3 side to the discharge path 10 of the cylinder head 7, and the discharge valve 11 is disposed below the discharge path 10 of the cylinder head 7. . The discharge valve 11 has a plurality of inflow holes in the outer peripheral portion, but no inflow hole is formed in the tip portion on the cylinder liner 3 side, so that the tip portion is the outlet of the valve head 6 by the biasing force of the internal spring. The valve can be closed by coming into contact with the end face on the cylinder head 7 side in the vicinity of the opening 21.

  When the piston 5 begins to expand toward the valve head 6 during the compression stroke, the discharge valve 11 opens against the biasing force of the internal spring by the pressure of the liquid fuel from the cylinder liner 3 side. Further, when the piston 5 is fully extended, the discharge valve 11 is brought into contact with the end face on the cylinder head 7 side in the vicinity of the outlet opening 21 of the valve head 6 by the biasing force of the internal spring and is closed again.

  As shown in FIG. 3, the above-described seal portion 30 includes, for example, six annular packings that are arranged side by side in a layered manner in the axial direction and each has an inner peripheral portion that follows the outer peripheral portion of the piston rod 12. The portions 35 to 40 and the two spacers 41 and 42 are formed.

  Each packing part 35-40 is formed by combining a plurality of rod packings 45, 46, 53, and these rod packings 45, 46, 53 are coaxially stacked in a layered manner in the axial direction. The rod packings 45, 46, 53 are, for example, flat in the radial direction and formed in an annular shape so that the piston rod 12 can be inserted into the inner peripheral portion. It is formed of a resin composite material.

The two spacer portions 41 and 42 disposed so as to sandwich the packing portion 39 from both sides in the axial direction are annular annular passages 41a and 42a formed in the outer peripheral portion, and the annular passages 41a and 42a.
And a plurality of radial passages 41b and 42b which are drilled toward the inner periphery.

  The annular passage 42 a and the radial passage 42 b of the spacer portion 42 located on the base side of the piston pump main body 1 communicate with a nitrogen gas supply passage 43 formed through the cylinder 2, and nitrogen is passed through the nitrogen gas supply passage 43. Gas is supplied to the annular passage 42 a and the radial passage 42 b of the spacer portion 42.

  The nitrogen gas supplied to the annular passage 42a and the radial passage 42b of the spacer portion 42 first applies a back pressure to the packing portion 39 to preload it. The nitrogen gas leaked to the spacer portion 41 on the tip end side through the packing portion 39 preloads the packing portions 38 to 35 on the tip end side with respect to the spacer portion 41 by applying back pressure.

  On the other hand, the annular passage 41a and the radial passage 41b of the spacer portion 41 communicate with a nitrogen gas exhaust passage 44 that passes through the piston 5 and extends to the outside of the piston pump main body 1, and the nitrogen gas passes through the nitrogen gas exhaust passage 44 through the atmosphere. It is exhausted inside.

  That is, the packing parts 35 to 39 disposed on the tip part side of the spacer parts 41 and 42 are pressurized by nitrogen gas so that liquid fuel does not leak from the seal part 30 to the outside as much as possible. A part of the liquid fuel leaking from the packing part 38 on the tip side of the spacer part 41 is diluted with nitrogen gas exhausted through the nitrogen gas exhaust path 44 and then exhausted into the atmosphere.

  As shown in FIG. 4, a seal portion (second seal portion) 52 that makes the connection box 50 and the actuator rod 61 protruding from the actuator 60 liquid-tight and air-tight on the base side of the connection box 50 described above. Is disposed. As shown in FIG. 5, a seal groove 51 is cut in the circumferential direction on the connection box 50 side, and a seal portion 52 is disposed in the seal groove 51.

  The seal portion 52 includes a seal ring 53 made of, for example, a fluororesin composite material, and an O-ring (press) that presses the seal ring 53 against the actuator rod 61 to make the connection box 50 and the actuator rod 61 airtight and airtight. Member) 54.

  Thus, by providing the sealing portion 52 on the base side of the connection box 50 to make the connection box 50 and the actuator rod 61 protruding from the actuator 60 liquid-tight and air-tight, Airtightness can be further ensured. Accordingly, even if the rod packings 45, 46, 53 are deformed or hardened due to a large temperature drop or the like, the release of liquid fuel into the atmosphere can be reliably suppressed.

  In particular, the seal portion 50 is made of a material having sufficient slidability even without oil supply, that is, a seal ring 53 made of a fluororesin composite material as an example of a self-lubricating material, and the seal ring 53 as an actuator. By forming the O-ring 54 that presses against the rod 61 to make the seal ring 53 and the actuator rod 61 liquid-tight and air-tight, there is no need to provide a special oiling mechanism for the seal portion 50. Sufficient slidability can be imparted between 53 and the actuator rod 61.

  Further, the inside of the seal groove 51 is liquid-tight and air-tight by compression deformation of the O-ring 54 made of an elastic material. Thereby, between the junction box 50 and the actuator rod 61 which protrudes from the actuator 60, the liquid-tightness and airtightness which were remarkably superior than before can be provided.

That is, the seal portion 52 has a relatively simple structure of being composed of the seal ring 53 and the O-ring 54 as described above, but extremely high liquid-tightness and air-tightness between the connection box 50 and the actuator rod 61. And is inexpensive and easy to maintain. The sealing performance of the seal ring 53 is extremely high. The seal ring 53 may be formed of a more optimal material other than the above-described fluororesin composite material.

  On the other hand, the inside of the junction box 50 is preloaded with nitrogen gas as follows. In FIG. 4, a solid line indicates a nitrogen gas path, a broken line indicates an electric path, and a one-dot chain line indicates a liquid fuel path. As shown in FIG. 4, a nitrogen gas supply source (gas supply source) 71 and an electropneumatic regulator (pressure) that adjusts the pressure of the nitrogen gas supplied from the nitrogen gas supply source 71 and supplies the nitrogen gas into the junction box 50. Adjustment unit) 72, a pressure sensor (pressure detection unit) 74 for detecting the supply pressure P of the liquid fuel compressed by the piston pump body 1 to the piston pump body 1, and the supply of the liquid fuel detected by the pressure sensor 74 Based on the pressure P, a controller 75 that operates the electropneumatic regulator 72 to adjust the pressure of the nitrogen gas supplied into the connection box 50 is provided.

  The above-described pressure sensor 74 is disposed in a liquid fuel recovery path 73 that is returned to a liquid fuel tank (not shown) and recovered, and detects the supply pressure P of the liquid fuel in the recovery path 73. The controller 75 electrically controls the electropneumatic regulator 72 to adjust the pressure of the nitrogen gas supplied into the connection box 50 to a pressure slightly higher than the supply pressure P of the liquid fuel detected by the pressure sensor 74.

  As a result, the air pressure in the junction box 50 is increased, and the amount of liquid fuel leaking from the protrusion 47 of the piston rod 12 provided at the end on the base side of the piston pump body 1 is reduced. Accordingly, even if the rod packings 45, 46, 53 are deformed or hardened due to a large temperature drop or the like, the release of liquid fuel into the atmosphere is greatly suppressed. The junction box 50 has sufficient strength to withstand the pressurization by nitrogen gas.

  Thus, it is optimal that the pressure of the nitrogen gas supplied into the junction box 50 for preloading is adjusted according to the supply pressure P of the liquid fluid to the piston pump body 1. As described above, the controller 75 operates the electropneumatic regulator 72 based on the supply pressure P of the liquid fuel detected by the pressure sensor 74 to adjust the pressure of the nitrogen gas for preload, thereby supplying the liquid fuel. Optimal preloading of the junction box 50 according to the pressure P can be performed.

  On the other hand, as shown in FIG. 4, a flow rate control valve (exhaust adjustment unit) 80 is disposed in the nitrogen gas exhaust passage 44, and a predetermined amount of nitrogen gas pre-pressurized the seal unit 30 passes through the flow rate control valve 80. It is released inside. That is, the nitrogen gas is adjusted to an appropriate amount and exhausted to the atmosphere.

  In addition, an electropneumatic regulator (exhaust adjustment unit) 81 controlled by the controller 75 is disposed, and the electropneumatic regulator 81 includes nitrogen gas that has pressurized the nitrogen gas exhaust path 44 and the connection box 50 described above. Is connected to a nitrogen gas exhaust path 82.

  That is, based on the supply pressure P of the liquid fuel detected by the pressure sensor 74, the controller 75 is connected to the nitrogen gas exhausted from the seal portion 30 of the piston pump body 1 through the nitrogen gas exhaust path 44 and the nitrogen gas exhaust path 82. By appropriately adjusting the exhaust flow rate with the nitrogen gas exhausted from the box 50, the nitrogen gas exhausted into the atmosphere through the flow control valve 80 was adjusted to a pressure slightly lower than the supply pressure P of the liquid fuel. Later it is discharged into the atmosphere.

  Thereby, the back pressure of the packing part 38 of the seal part 30 is held at a predetermined pressure. Thereby, the back pressure with respect to the packing parts 35 to 39 is optimally maintained, and even if there is a large temperature drop or the like and the rod packings 45, 46, 53 are deformed or hardened, they pass through the nitrogen gas exhaust passage 44. The release of liquid fuel into the atmosphere is greatly suppressed.

  Here, as described above, since the nitrogen gas in the junction box 50 is adjusted to a pressure slightly higher than the supply pressure P of the liquid fuel, in the electropneumatic regulator 81, the nitrogen gas exhaust path extending from the junction box 50. Nitrogen gas from the 82 side flows into the nitrogen gas exhaust path 44 extending from the seal portion 30 of the piston pump body 1.

  As a result, the pressure of the nitrogen gas in the nitrogen gas exhaust passage 44 can be appropriately maintained, and the electropneumatic regulator 72 and the electropneumatic regulator 81 are exposed to an inert gas. Since only a certain nitrogen gas is used, corrosion hardly occurs and the durability of the electropneumatic regulators 72 and 81 is sufficiently secured.

  Here, in the packing parts 35-40 in which a plurality are arranged in the axial direction of the piston rod 12, the pressure acting on each packing part 35-40 of the supply pressure of the liquid fuel received by each packing part 35-40. Minimizing the difference as much as possible is extremely important for ensuring the liquid tightness, air tightness and durability of the rod packings 45, 46, 53, as well as the overall liquid tightness, air tightness and durability of the seal portion 30. Excessive exhaust from a specific point goes against it.

  As described above, by newly providing a mechanism for optimally adjusting the exhaust pressure of nitrogen gas used for pressurization into the atmosphere, each of the supply pressures of the liquid fuel received by the packing portions 35 to 40 The pressure difference acting on the packing parts 35 to 40 can be reduced, respectively, and the liquid tightness, air tightness and durability of the rod packings 45, 46 and 53 and the entire seal part 30 are remarkably improved.

  FIG. 6 shows a piston pump device different from that shown in FIG. Portions common to FIG. 4 are denoted by the same reference numerals.

  An electropneumatic relief valve (pressure control valve) 85 operated by a controller 75 is disposed in the nitrogen gas exhaust path 44 of nitrogen gas pre-pressurized with the above-described seal portion 30, and the nitrogen gas in the nitrogen gas exhaust path 44 is After being adjusted to a predetermined pressure through the electropneumatic relief valve 85, it is discharged into the atmosphere.

  That is, based on the liquid fuel supply pressure P detected by the pressure sensor 74, the controller 75 electrically controls the operation of the electropneumatic relief valve 85 to control the pressure of the nitrogen gas exhausted through the nitrogen gas exhaust path 44. Adjust optimally and directly. By using the electropneumatic relief valve 85 which is a pressure control valve, a simpler configuration than the piston pump device shown in FIG. 4 can be obtained.

  As a result, the preload of the seal portion 30 is optimized, and even when the rod packings 45, 46, 53 are deformed or hardened due to a large temperature drop or the like, the liquid fuel is greatly released into the atmosphere. It is suppressed. The rest is the same as the piston pump device shown in FIG.

  The above-described piston pump device is merely an example, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Piston pump main body 2 Cylinder 3 Cylinder liner 4 Cylinder head chamber 5 Piston 6 Valve head 7 Cylinder head 8 Supply port 9 Discharge port 10 Discharge path 11 Discharge valve 12 Piston rod (rod part)
13 Valve housing chamber 16 Protrusion 17 Suction passage 18 Piston ring groove 19 Piston ring 21 Exit opening 28, 29 Discharge port 30 Seal portion 31 Retainer 32 Coil springs 35-40 Packing portions 41, 42 Spacers 41a, 42a Annular passage 41b, 42b Radial passage 43 Nitrogen gas supply passage 44 Nitrogen gas exhaust passage 45, 46, 53 Rod packing 47 Projection port 50 Connection box (intermediate part)
51 Seal groove 52 Seal part (second seal part)
53 Seal ring 54 O-ring (Pressing member)
60 Actuator 61 Actuator rod (rod part)
71 Nitrogen gas supply source (gas supply source)
72 Electro-pneumatic regulator (pressure regulator)
73 Recovery path 74 Pressure sensor (pressure detector)
75 Controller 80 Flow control valve (exhaust adjustment part)
81 Electropneumatic regulator (pressure adjustment part)
82 Nitrogen gas exhaust passage 85 Electropneumatic relief valve (pressure control valve)
P Supply pressure

Claims (10)

  A cylinder (2) having a cylinder liner (3) therein, a piston (5) that is reciprocally inserted into the cylinder liner and compresses a fluid to be compressed, and is connected to the piston and within the cylinder A piston rod (12) that is inserted to reciprocate the piston in the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder to close the space between the piston rod and the cylinder. A piston pump body having (30), and an actuator (60) in which an actuator rod (61) is coupled to the piston rod of the piston pump body to reciprocate the piston in the cylinder via the piston rod. The piston pump is disposed between the piston pump body and the actuator. An intermediate part (50) that tightly covers the protrusion (47) of the piston rod provided at the end on the base side of the body from the outside, and a gas that supplies gas into the intermediate part to increase the air pressure in the intermediate part A piston pump device comprising a supply mechanism (71, 72, 74, 75).   The gas supply mechanism includes a gas supply source (71) for supplying the gas, and a pressure adjusting unit (72) for adjusting the pressure of the gas supplied from the gas supply source and supplying the pressure to the intermediate portion (50). And a pressure detector (74) for detecting the supply pressure (P) of the fluid to be compressed to the piston pump body (1), and the supply pressure of the fluid to be compressed detected by the pressure detector. The piston pump device according to claim 1, further comprising a controller (75) for operating the pressure adjusting unit to adjust the pressure of the gas supplied to the intermediate unit.   The controller (75) causes the pressure adjusting part (72) to adjust the pressure of the gas supplied to the intermediate part (50) to be higher than the supply pressure (P) of the compressed fluid. The piston pump device according to claim 2, wherein   A cylinder (2) having a cylinder liner (3) therein, a piston (5) that is reciprocally inserted into the cylinder liner and compresses a fluid to be compressed, and is connected to the piston and within the cylinder A piston rod (12) that is inserted to reciprocate the piston in the cylinder liner, and is disposed between the piston rod and the cylinder so as to close the space between the piston rod and the cylinder and externally. A piston pump main body (1) having a seal portion (30) preloaded by gas supplied from the exhaust, and exhaust for exhausting the gas supplied to the seal portion of the piston pump main body for pressurization to the outside A passage (44) and an exhaust adjustment mechanism (74, 75, which is disposed in the exhaust passage and adjusts an exhaust state amount of the gas exhausted from the exhaust passage) 0,81,85) and a piston pump apparatus characterized by comprising a.   The exhaust adjustment mechanism includes an exhaust adjustment unit (80, 81, 85) for adjusting the exhaust state quantity, and a pressure detection unit (74) for detecting a supply pressure (P) of the compressed fluid to the piston pump body. And a controller (75) for operating the exhaust adjustment unit based on the supply pressure of the fluid to be compressed detected by the pressure detection unit. .   The exhaust state quantity is an exhaust flow rate of the gas, and the exhaust adjustment unit includes a flow control valve (80) capable of adjusting the exhaust flow rate, and the flow control valve includes the exhaust passage (44). The piston pump device according to claim 5, wherein the exhaust flow rate of the gas exhausted to the outside is adjusted to a predetermined amount. The exhaust state quantity is an exhaust pressure of the gas, and the exhaust adjustment unit includes a pressure control valve (81, 85) capable of adjusting the exhaust pressure, and the pressure control valve includes the exhaust path ( The piston pump device according to claim 5 or 6, wherein the exhaust pressure of the gas exhausted to the outside from (44) is adjusted to a predetermined pressure.   The controller (75) causes the exhaust adjustment mechanism (74, 75, 80, 81, 85) to adjust so that the exhaust pressure of the gas is lower than the supply pressure (P) of the compressed fluid. The piston pump device according to any one of claims 5 to 7, wherein   A cylinder (2) having a cylinder liner (3) therein, a piston (5) that is reciprocally inserted into the cylinder liner and compresses a fluid to be compressed, and is connected to the piston and within the cylinder A piston rod (12) that is inserted to reciprocate the piston within the cylinder liner, and a seal portion that is disposed between the piston rod and the cylinder to close the space between the piston rod and the cylinder. (30) and an actuator rod (61) connected to the piston rod of the piston pump main body to reciprocate the piston in the cylinder via the piston rod (30) 60), and the piston rod or the axle projecting from the piston pump body toward the base side. A rod portion composed of the actuator rod protruding from the rotor to the tip end side, and a piston rod disposed between the piston pump body and the actuator and provided at an end portion on the base side of the piston pump body. An intermediate portion (50) that covers the projection port and the rod portion from the outside, and the intermediate portion and the rod portion that are disposed between the intermediate portion and the rod portion and on the base side of the intermediate portion. And a second seal portion (52) that closes the space between the piston pump device and the piston pump device.   The second seal portion (52) includes a seal ring (53) made of a self-lubricating material, and presses the seal ring against the rod portion to close the space between the seal ring and the rod portion. The piston pump device according to claim 9, further comprising a pressing member (54) to be moved.

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