JP4918605B2 - Booster pump for cryogenic fluid - Google Patents

Description

  The present invention relates to a low-temperature fluid booster pump that compresses and pressurizes a low-temperature fluid.

  2. Description of the Related Art Conventionally, a piston type pump having a piston ring in a piston head is known as a low pressure fluid pressure pump that compresses and pressurizes a low temperature (0 ° C. or lower) fluid (for example, hydrogen) (for example, non-patent). Reference 1).

Endo Takuya et al., “New Energy Vehicle”, Sankai-do, January 1995, p. 221-222

In addition, as a suction valve used in such a booster pump for low-temperature fluid, the pressure in the cylinder is negative (pressure lower than the pressure of the low-temperature fluid supplied to the cylinder (the low-temperature fluid before being compressed)). When it becomes, the thing which becomes an open state by the difference between the pressure in the cylinder and the pressure of the cryogenic fluid (in the atmospheric pressure state) supplied to the cylinder (such as a check valve (or check valve)) Are known.
However, in a booster pump for a low-temperature fluid equipped with such a suction valve, the suction valve is opened if the pressure in the cylinder does not fall below the pressure of the low-temperature fluid supplied to the cylinder (at atmospheric pressure). Therefore, there is a problem that the pump efficiency is lowered.
In addition, if the low-temperature fluid is gasified in the cylinder, the pressure in the cylinder is further increased, and it takes more time to open the suction valve, and the pump efficiency is further deteriorated. There was also a point.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a booster pump for low-temperature fluid that can improve pump efficiency.

The present invention employs the following means in order to solve the above problems.
The pressurizing pump for low-temperature fluid according to the present invention has a piston having a plurality of ring grooves formed on the outer peripheral surface, a plurality of piston rings arranged in the ring groove, and the piston and the piston ring formed therein. A cryogenic fluid booster pump comprising: a cylinder block accommodated in the cylinder, and a suction valve having a valve body that opens and closes a flow path of the cryogenic fluid that is sucked into the cylinder at 0 ° C. or less. And a biasing member for biasing the valve body in the opening direction and maintaining the valve body in an open state in a state where the pressure in the cylinder is equal to or slightly higher than the atmospheric pressure. Yes.
According to such a low-pressure fluid booster pump, the valve body is always urged by the urging means in the direction of opening the flow path into the cylinder (for example, upward in FIGS. 1 and 2). When the urging force of the urging means overcomes the force (force for closing the flow path) acting on the valve body, the flow path is opened. That is, in the intake stroke, even if the pressure in the cylinder is equal to or slightly higher than the atmospheric pressure, the valve body is lifted and the flow path is opened. When the piston moves backward toward the top dead center and the pressure in the cylinder becomes lower than the atmospheric pressure, a low-temperature fluid (in the atmospheric pressure state) flows into the cylinder. Thereby, the liquid quantity of the low temperature fluid which flows in (supplied) in a cylinder can be increased, and pump efficiency can be improved.
Further, since the valve body is always urged in the opening direction (for example, upward in FIGS. 1 and 2) by the urging means, the pressure in the cylinder is equal to or higher than the atmospheric pressure in the intake stroke. Even if it is slightly higher, the valve body can be reliably moved in the opening direction, and the flow path can be opened. Therefore, the flow path into the cylinder can be opened without increasing the pressure of the low-temperature fluid flowing into (supplied into) the cylinder, the apparatus can be simplified, and the manufacturing cost can be reduced. Can be planned.
Furthermore, according to such a booster pump for low-temperature fluid, the low-temperature fluid gasified in the dead volume in the cylinder can be discharged to the outside of the cylinder block through the joint of each piston ring. In the next (subsequently performed) suction stroke, the low-temperature fluid can be introduced without being affected by the dead volume, and the amount of the low-temperature fluid flowing (supplied) into the cylinder can be increased. Thus, the pump efficiency can be further improved.

  According to the present invention, there is an effect that the pump efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a principal part schematic longitudinal cross-sectional view which shows 1st Embodiment of the pressure | voltage rise pump for low temperature fluids by this invention, Comprising: (a) is a figure which shows the state in which a piston exists in the position of a top dead center, (b) is a piston. It is a figure which shows the state which is in the position of a bottom dead center. It is a figure which shows 2nd Embodiment of the pressure | voltage rise pump for cryogenic fluid by this invention, Comprising: (a) is a principal part schematic longitudinal cross-sectional view which shows the state in which a piston exists in the position of a top dead center, (b) is a piston below FIG. 3 is a schematic vertical sectional view of a main part showing a state at the position of a dead center, and FIG. It is a figure which shows 3rd Embodiment of the pressure | voltage rise pump for cryogenic fluids by this invention, Comprising: (a) is a principal part schematic longitudinal cross-sectional view which shows the state which has a piston in the position of a bottom dead center, (b) is (a). It is bb arrow sectional drawing of.

Hereinafter, a first embodiment of a booster pump for low-temperature fluid according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, a cryogenic fluid booster pump 10 according to this embodiment includes a piston 11, a piston rod (not shown), a cylinder block 12, and a suction valve 13 as main elements. It is.
The piston 11 is a member having a substantially cylindrical shape that is accommodated in a cylinder 12a formed inside the cylinder block 12 so as to be able to reciprocate. The piston 11 has a low-temperature fluid (for example, a lower end surface in FIG. 1) , Liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.) can be compressed.
A ring groove 11a is formed on the outer peripheral surface of the piston 11 (that is, the surface facing the inner peripheral surface (cylinder wall) of the cylinder 12a). A piston ring 14 made of (tetrafluoroethylene) is disposed.

The piston rod is a substantially rod-like member that has a circular shape in cross section, and has one end connected to the center of the other end surface of the piston 11 and the other end connected to a power transmission unit (not shown). .
The power transmission unit linearly reciprocates the piston rod in a vertical direction with a stroke of, for example, 2 mm by power from a drive source (not shown).

The cylinder block 12 is a member having a generally hollow cylindrical cylinder 12a therein. One end (lower end in FIG. 1) of the cylinder block 12 is an opening, and a suction valve 13 is provided in the opening. On the other hand, the other end of the cylinder block 12 is a closed portion except for a through hole (not shown) through which the piston rod passes, and a low temperature seal (not shown) is provided between the piston rod and the through hole. Is provided.
Further, a fluid outlet 15 is provided on the side surface of the cylinder block 12 (for example, the right side surface in FIG. 1) through which a low-temperature fluid compressed by one end surface of the piston 11 (pressure increased to about 1.3 MPa) flows out. A non-illustrated check valve (check valve) is provided downstream of the fluid outlet 15. This check valve opens when a fluid pressure of a predetermined pressure (for example, 1.2 MPa) or more is applied (applies), and closes when the fluid pressure becomes less than the predetermined pressure.

The intake valve 13 is configured with a valve body 16 and a valve casing 17 as main elements.
The valve body 16 includes a cylindrical rod 18 and a substantially frustoconical head 19 that is provided on one end side of the rod 18 and expands in diameter as the distance from the rod 18 increases.
On the other end portion (the lower end portion in FIG. 1) of the rod 18 is formed an enlarged diameter portion 20 whose flat one end surface is a spring receiving surface 20a.
A flat one end surface (upper end surface in FIG. 1) 19a of the head 19 is a pressure receiving surface against which a low-temperature fluid compressed by one end surface of the piston 11 is pressed, and a sheet is formed on the side surface along the circumferential direction. A surface 19b is formed.

  As shown in FIG. 1, the valve casing 17 is a member having a substantially T-shaped cross-sectional view, and a plurality (for example, eight (see FIG. 2C)) are provided on the outer peripheral portion along the circumferential direction. ) Is formed in the plate thickness direction (vertical direction in FIG. 1). Further, a valve seat 17b that matches the seat surface 19b of the head 19 is formed on one end surface (the upper end surface in FIG. 1) of the valve casing 17, and when the seat surface 19b is seated on the valve seat 17b. All of the outlet ends of the fluid inlet 17a are completely closed.

In the central portion of the valve casing 17 on the other end surface (lower end surface in FIG. 1) side, a slide that supports and supports the enlarged diameter portion 20 of the rod 18 and the shaft portion of the rod 18 (the portion other than the enlarged diameter portion 20). A recess 17c that accommodates the bearing 21, the spring (biasing member) 22 that urges the valve body 16 toward the piston 11 (the upper side in FIG. 1), and the spring receiver 23 is formed.
The slide bearing 21 is disposed between the outer peripheral surface of the shaft portion of the rod 18 and the inner wall surface of the recess 17c so as to be in contact with the outer peripheral surface of the shaft portion of the rod 18 and a part of the inner wall surface of the recess 17c. Yes. Further, one end surface (the lower end surface in FIG. 1) of the sliding bearing 21 is a receiving surface that comes into contact with the other end surface of the diameter-enlarged portion 20. One end surface of the sliding bearing 21 and the other end surface of the enlarged diameter portion 20 abut when the valve body 16 is pressed to the piston 11 side by the force of the spring 22 and moves to the piston 11 side by a predetermined distance, Thereby, the movement to the piston 11 side of the valve body 16 is restrained. The sliding bearing 21 also serves as a seal member that prevents the low-temperature fluid in the cylinder 12a from flowing into the recess 17c.

  A spring receiver 23 is provided (inserted) at one end of the recess 17c (the end opposite to the side where the sliding bearing 21 is disposed), and the spring receiving surface 20a of the enlarged diameter portion 20 is provided. A spring 22 is disposed between one end surface of the spring receiver 23 (the upper end surface in FIG. 1). The spring 22 biases the valve body 16 toward the piston 11 as described above. Therefore, when the force acting on the one end surface 19a of the head 19 (the force pressing the valve body 16 toward the spring 22) is smaller than the force of the spring 22, the state shown in FIG. When the force of the spring 22 cannot completely resist (cannot overcome) the force acting on the one end surface 19a of the head 19, all the outlet ends of the fluid inlet 17a are completely And the state shown in FIG. 1B is taken.

With the above configuration, in the low-temperature fluid booster pump 10 according to the present embodiment, the valve body 16 is pressed toward the piston 11 by the biasing force of the spring 22 in the suction process, and the seat surface 19b is separated from the valve seat 17b. All the outlet ends of the inflow port 17a are opened so that a low-temperature fluid in an atmospheric pressure state flows into the cylinder 12a (see FIG. 1A).
Further, in the compression stroke, the low temperature fluid compressed by the one end surface of the piston 11 acts on the one end surface 19a of the head 19, and when this force overcomes the urging force of the spring 22, the valve body 16 gradually moves into the valve casing. The seat surface 19b is seated on the valve seat 17b, and all the outlet ends of the fluid inlet port 17a are completely closed. Thereafter, the piston 11 further moves toward the head 19, whereby the low temperature fluid is further compressed between the one end surface of the piston 11 and the one end surface 19 a of the head 19, and the low temperature fluid becomes a desired pressure (for example, , About 1.3 MPa), the pressurized low temperature fluid is led out of the cylinder block 12 from the fluid outlet 15.

According to the cryogenic fluid booster pump 10 according to the present embodiment, the valve body 16 is always urged by the spring 22 in the opening direction (upward in FIG. 1), and the urging force of the spring 22 is applied to one end surface of the head 19. When the force acting on 19a is overcome, all of the outlet ends of the fluid inlet port 17a are opened. That is, in the intake stroke, even if the pressure in the cylinder 12a is equal to or slightly higher than the atmospheric pressure, the valve body 16 is lifted and all the outlet ends of the fluid inlet 17a are opened. Then, when the piston 11 moves backward toward the top dead center and the pressure in the cylinder 12a becomes lower than the atmospheric pressure, the low-temperature fluid (in the atmospheric pressure state) flows into the cylinder 12a. Thereby, the liquid quantity of the low-temperature fluid which flows in (supply) in the cylinder 12a can be increased, and pump efficiency can be improved.
Further, since the valve body 16 is always urged in the opening direction (upward in FIG. 1) by the spring 22, the pressure in the cylinder 12a is equal to or slightly higher than the atmospheric pressure in the intake stroke. The valve body 16 can be reliably moved in the opening direction, and all the outlet ends of the fluid inlet port 17a can be opened. Therefore, the fluid inlet 17a can be opened without increasing the pressure of the low-temperature fluid flowing (supplied) into the cylinder 12a, the apparatus can be simplified, and the manufacturing cost can be reduced. be able to.

A second embodiment of the cryogenic fluid booster pump according to the present invention will be described with reference to FIG.
The cryogenic fluid booster pump 30 in this embodiment is different from that in the first embodiment described above in that a suction valve 31 is provided instead of the suction valve 13. Since other components are the same as those in the above-described embodiment, description of these components is omitted here.
In addition, the same code | symbol is attached | subjected to the member same as 1st Embodiment mentioned above.

The intake valve 31 is configured with a valve body 32 and a valve casing 33 as main elements.
The valve body 32 is a ring-shaped (donut-shaped) plate-like member (see FIG. 2C) having an opening 32a having a circular shape in plan view at the center, and one end of the cylinder block 12 (the lower side in FIG. 2). And is slidable along the longitudinal direction (vertical direction in FIG. 2) of the cylinder block 12 in the recess 12b.
One end surface (upper end surface in FIG. 2) 32b of the valve body 32 is a pressure receiving surface against which a low-temperature fluid compressed by one end surface of the piston 11 is pressed, and the other end surface (lower end surface in FIG. 2) 32c. Is a seat surface and a spring receiving surface.

  As shown in FIG. 1, the valve casing 33 is a member that has a substantially convex shape in a cross-sectional view, and a plurality (for example, eight (see FIG. 2 (c))) of the outer peripheral portion along the circumferential direction. The fluid inlet 33a is formed in the plate thickness direction (vertical direction in FIG. 2). Further, a valve seat 33b that matches the seat surface (other end surface) 32c of the valve body 32 is formed on one end surface (the upper end surface in FIG. 2) of the valve casing 33, and the seat surface 32c is on the valve seat 33b. All the outlet ends of the fluid inflow port 33a are completely closed when seated on.

  Further, a spring receiver 34 is provided (inserted) on the inlet side of the fluid inlet 33 a (the other end surface side of the valve casing 33 (the lower end surface side in FIG. 2)). A spring (biasing member) 35 is disposed between the surface (the other end surface) 32c and one end surface (the upper end surface in FIG. 2) of the spring receiver 34. The spring 35 causes the valve body 32 to be a piston. Therefore, when the force acting on the one end face 32b of the valve body 32 (the force that presses the valve body 32 toward the spring 35) is smaller than the force of the spring 35, FIG. 2 (a), and the force of the spring 35 cannot completely resist (cannot overcome) the force acting on the one end surface 32b of the valve body 32. And all of the outlet ends of the fluid inlet 33a are completely closed. 2 (b) The force acting on the one end surface 32b of the valve body 32 changes the inner diameter of the opening 32a, and the pressure receiving surface (one end surface) 32b of the valve body 32 changes. It can be easily adjusted by changing the area.

With the above configuration, in the low-temperature fluid booster pump 30 according to the present embodiment, the valve body 32 is pressed toward the piston 11 by the urging force of the spring 35 in the suction process, and the seat surface 32c is separated from the valve seat 33b. All the outlet ends of the inflow port 33a are opened so that a low-temperature fluid in an atmospheric pressure state flows into the cylinder 12a (see FIG. 2A).
In the compression stroke, the low temperature fluid compressed by the one end surface of the piston 11 acts on the one end surface 32b of the valve body 32, and when this force overcomes the urging force of the spring 35, the valve body 32 gradually moves to the valve. The sheet surface 32c is seated on the valve seat 33b while being pressed toward the casing 33, and all the outlet ends of the fluid inlet 33a are completely closed. Thereafter, when the piston 11 further moves toward the valve body 32, the low-temperature fluid is further compressed between the one end surface of the piston 11 and the one end surface 32b of the valve body 32, so that the low-temperature fluid becomes a desired pressure. When pressurized (for example, about 1.3 MPa), the pressurized low-temperature fluid is led out of the cylinder block 12 from the fluid outlet 15.

  The operational effects of the cryogenic fluid booster pump 30 according to the present embodiment are the same as those of the first embodiment described above, and therefore the description thereof is omitted here.

A third embodiment of a booster pump for a cryogenic fluid according to the present invention will be described with reference to FIG.
The low-temperature fluid booster pump 40 according to this embodiment is configured so that the joint 42b of each piston ring is always located on the fluid outlet 15 side, as described above. Different from that. Since other components are the same as those in the above-described embodiment, description of these components is omitted here.
FIG. 3 shows a cryogenic fluid booster pump having the same configuration as the cryogenic fluid booster pump described in the second embodiment, which is the same as that of the first embodiment and the second embodiment described above. The same reference numerals are given to the members.

As shown in FIG. 3B, in each ring groove 41a of the piston 41 located on the side opposite to the fluid outlet 15 in the horizontal plane, along the longitudinal direction (vertical direction in FIG. 3A). A convex portion 41b is formed.
In addition, a convex portion is formed on the inner peripheral surface of each piston ring 42 accommodated in the ring groove 41a that faces the convex portion 41b (that is, the inner peripheral surface located on the side opposite to the fluid outlet 15 in the horizontal plane). A convex portion 42a is formed toward 41b.
Backup rings 43 are accommodated between the piston 41 and the piston ring 42, respectively. The backup ring 43 is a ring-shaped member having a joint on the side opposite to the fluid outlet 15 in the horizontal plane (that is, having a joint on the side opposite to the joint 42b of the piston ring 42), and one end surface of the joint Between the other end surface, the convex portion 41b formed in the ring groove 41a and the convex portion 42a of the piston ring 42 are positioned so that the piston ring 42 does not rotate with respect to the piston 42 and the backup ring 43 (that is, The joint 42b of each piston ring 42 is always located on the fluid outlet 15 side).

According to the booster pump 40 for low-temperature fluid according to the present embodiment, the joint 42b of each piston ring 42 is configured to be always located on the fluid outlet 15 side, and gasifies in the dead volume in the cylinder 12a. The low-temperature fluid that has been introduced is guided toward the other end side of the cylinder block 12 through the joint 42b of the piston ring 42, and is then guided to the outside of the cylinder block 12 from a gas outlet that is not shown.
As described above, in the low-temperature fluid booster pump 40 according to the present embodiment, the low-temperature fluid gasified in the dead volume in the cylinder 12 a is discharged to the outside of the cylinder block 12 through the joint 42 b of each piston ring 42. Therefore, in the next (subsequently performed) suction stroke, the cryogenic fluid can be introduced into the dead volume, and the amount of the cryogenic fluid flowing (supplied) into the cylinder 12a is increased. And pump efficiency can be further improved.
Other functions and effects are the same as those of the first embodiment and the second embodiment described above, and thus description thereof is omitted here.

In addition, this invention is not limited to the thing of embodiment mentioned above, It can deform | transform suitably as needed. For example, the piston ring 42 described in the third embodiment does not necessarily have to be configured so that the joints 42b of all the piston rings 42 face the fluid outlet 15, and at least the fluid outlet 15 It suffices that only the abutment 42b of the piston ring 42 that is close (the lowest position in FIG. 3) faces the fluid outlet 15 side.
Further, the opening / closing timing of the valve bodies 16 and 32 and the amount of the low temperature fluid flowing into the cylinder can be easily changed by adjusting the spring force (biasing force) of the springs 22 and 35.

DESCRIPTION OF SYMBOLS 10 Booster pump 11 for low temperature fluids Piston 11a Ring groove 12 Cylinder block 12a Cylinder 13 Suction valve 14 Piston ring 15 Fluid outlet 16 Valve body 22 Spring (biasing member)
30 Low Pressure Fluid Booster Pump 31 Suction Valve 32 Valve Body 35 Spring (Biasing Member)
40 Low Pressure Fluid Booster Pump 41 Piston 41a Ring Groove 42 Piston Ring 42b Joint

Claims (1)

A piston having a plurality of ring grooves formed on the outer peripheral surface, a plurality of piston rings arranged in the ring groove, and a cylinder block for accommodating these pistons and piston rings in a cylinder formed therein A low-temperature fluid booster pump comprising a suction valve having a valve body for opening and closing a flow path of a low-temperature fluid sucked into the cylinder at 0 ° C. or less,
There is provided an urging member for urging the valve body in the opening direction and maintaining the valve body in the open state in a state where the pressure in the cylinder is equal to or slightly higher than the atmospheric pressure. A booster pump for low temperature fluids.

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