Cryogenic pump

Abstract

The present invention relates to a cryogenic pump in which a filling fluid of the same type as a transfer fluid is provided in an inner space to flow to the left and right of a slider. The cryogenic pump according to the present invention includes: a cylindrical main casing (10) having a flow space (12) formed therein; a slider (30) provided inside the main casing (10) and configured to slidingly move inside the main casing (10); a pair of cylinders (20, 20') having an inner diameter smaller than the inner diameter of the main casing (10) and extending stepwise symmetrically at both sides from both ends of the main casing (10); a pair of pistons (40, 40') extending at both sides from both ends of the slider (30) and configured to slidingly move inside the pair of cylinders (20, 20'); a stator (35) provided outside the slider (30) and forcing the slider (30) to move by means of magnetic force; inlets (50, 50') and outlets (60, 60') that are formed on one side of the pair of cylinders (20, 20') and serve as entrance and exit passages for the transfer fluid, wherein the transfer fluid (T) flowing through the inlets (50, 50') and the outlets (60, 60') is formed of the same fluid as the filling fluid (C) filled inside the main casing (10). The present invention is advantageous in that it is unnecessary to maintain airtightness inside the pump.

Description

cryogenic pump

[0001] The present invention relates to a cryogenic pump, and more particularly, to a cryogenic pump in which a filling fluid of the same type as a transport fluid is provided in an internal space and flows to the left and right of a slider.

[0002] Cryogenic pumps pressurize and transport cryogenic fluids such as oxygen, nitrogen, argon, hydrocarbons, and natural gas (LNG) in liquid or gaseous states. Cryogenic pumps are increasingly being used in industry. For example, hydrogen vehicles store high-pressure hydrogen in storage tanks and use it as fuel, receiving it from hydrogen refueling stations similar to conventional gasoline and gasoline refueling stations. Therefore, hydrogen refueling stations need to be equipped with cryogenic pumps capable of generating high pressure to move hydrogen from a central storage facility to the vehicle's storage tank.

[0003] Conventional cryogenic reciprocating pumps use a mechanical crank drive to pump cryogenic fluids by horizontally reciprocating pistons. However, the mechanical nature of this method generates frictional heat during the drive, and this heat is transferred to the fluid, reducing pumping efficiency.

[0004] Additionally, conventional cryogenic pumps provide a structure in which the plunger part of the linear motor is surrounded by a vacuum can to prevent heat of the ambient air at room temperature from being transferred to the fluid through the pump.

[0005] However, there was a problem in that some of the fluid could flow into the sliding room through the gap between the piston and plunger of the linear motor, and since no other parts other than the plunger part were equipped with separate heat shielding means, it was impossible to prevent the heat of the outside air from invading other parts of the linear motor.

[0006] To improve this, Korean Patent No. 10-1766010 discloses a reciprocating piston electromagnetic pump in which coils that generate magnetic fields are independently installed on the outer periphery of the cylinder in a number corresponding to the length of the cylinder to generate an independent magnetic field, and the reciprocating movement distance and movement speed of the piston within the cylinder can be freely controlled.

[0007] However, this Korean Patent No. 10-1766010 still had the disadvantage of not being able to effectively block external heat intrusion because the entire pump was not shielded in a vacuum state like conventional cryogenic pumps.

[0008] Accordingly, Korean Patent No. 10-2382040 discloses a cryogenic dual reciprocating pump that provides a structure in which most of a linear motor is surrounded by a vacuum layer to isolate the cryogenic fluid to be pumped from the outside air, thereby blocking heat penetration into the cryogenic fluid, and improving pumping efficiency through a dual piston.

[0009] However, even in these cryogenic pumps, the cryogenic fluid being pumped and the working fluid (gas) filling the pump are different, requiring sealing to separate the two. Furthermore, this sealing often fails to function properly, particularly after prolonged use.

[0010] Accordingly, the purpose of the present invention is to solve the problems of the prior art as described above, and to provide a cryogenic pump in which the cryogenic transport fluid to be pumped and the filling fluid filled inside the pump are made of the same material.

[0011] In addition, the purpose of the present invention is to provide a cryogenic pump that fundamentally blocks heat conduction between the outside air and the cryogenic fluid by vacuum insulation.

[0012] According to the features of the present invention for achieving the above-described purpose, the cryogenic pump (1) according to the present invention comprises: a cylindrical main casing (10) having a flow space (12) formed therein; a slider (30) provided inside the main casing (10) and configured to slide and flow inside the main casing (10); a pair of cylinders (20, 20') having an inner diameter smaller than the inner diameter of the main casing (10) and extending symmetrically from both ends of the main casing (10) in steps; a pair of pistons (40, 40') extending from both ends of the slider (30) to both ends and configured to slide and flow inside the pair of cylinders (20, 20'); a stator (35) provided on the outside of the slider (30) and forcing the slider (30) to flow by magnetic force; It has a configuration including an inlet (50, 50') and an outlet (60, 60') formed on one side of the pair of cylinders (20, 20') and serving as an inlet and outlet passage for the transport fluid; the transport fluid (T) flowing through the inlet (50, 50') and outlet (60, 60') is characterized in that it is the same fluid as the filling fluid (C) filled inside the main casing (10).

[0013] The above slider (30) is characterized by having an orifice (34) formed through which a filling fluid (C) filled inside the main casing (10) moves.

[0014] The above orifices (34) are characterized in that a plurality of them are formed at equal intervals on the slider (30).

[0015] The above main casing (10) is further characterized by being provided with a gas discharge port (80) that guides the discharge of gas inside the main casing (10).

[0016] The above gas discharge port (80) is further characterized by having an opening / closing valve that opens / closes depending on the pressure inside the main casing (10).

[0017] The cryogenic pump according to the present invention has the following effects.

[0018] First, in the present invention, the cryogenic transport fluid to be pumped and the fill fluid filling the pump are made of the same material. Therefore, even if the fill fluid inside the pump and the external transport fluid mix, no problems arise, eliminating the need for efforts to maintain sealing between components.

[0019] Furthermore, the present invention eliminates the need for a gap seal between the piston and the cylinder, and the slider is provided with an orifice through which the filling fluid can flow. Therefore, the slider, driven by the stator, facilitates movement, thereby reducing the need for power supply or motor load for generating electromagnetic force.

[0020] In addition, the present invention forms a vacuum space of a predetermined size on the outside of the main casing and the cylinder by forming a vacuum casing further on the outside. Therefore, there is an advantage in that heat conduction between the outside air and the cryogenic fluid is fundamentally blocked by vacuum insulation.

[0021] Fig. 1 is a cross-sectional view showing the configuration of a preferred embodiment of a cryogenic pump according to the present invention.

[0022] Figure 2 is a cross-sectional view taken along line AA of Figure 1.

[0023] Hereinafter, the cryogenic pump according to the present invention will be described in detail with reference to the attached drawings.

[0024] FIG. 1 illustrates a configuration of one embodiment of a cryogenic pump according to the present invention in a sectional view, and FIG. 2 illustrates an AA sectional view (side sectional view) of the cryogenic pump illustrated in FIG. 1.

[0025] As shown in these drawings, the cryogenic pump (1) according to the present invention is composed of a cylindrical main casing (10) having a flow space (12) formed therein, a slider (30) that slides and flows inside the main casing (10), a pair of cylinders (20, 20') that extend symmetrically from both ends of the main casing (10) to each other in steps, a pair of pistons (40, 40') that extend from both ends of the slider (30) to each other and slide and flow inside the pair of cylinders (20, 20'), a stator (35) that is provided on the outside of the slider (30) and forces the slider (30) to flow by magnetic force, and an inlet (50, 50') and an outlet (60, 60') that serve as entrance and exit passages for the transported fluid.

[0026] The above main casing (10) may be formed in a cylindrical shape with left and right sides open, and a flow space (12) in which the slider (30) flows is formed inside the main casing (10). A filling fluid (C) may be filled in the flow space (12).

[0027] The above fluid space (12) can be divided into a left space (12') formed on the left side of the slider (30) and a right space (12") formed on the right side, as shown, and the sizes of the left space (12') and the right space (12") change in inverse proportion to each other by the left and right movement of the slider (30).

[0028] The above slider (30) is provided inside the main casing (10) as shown, and may have a cylindrical shape with a predetermined thickness. The slider (30) can slide left and right inside the main casing (10) by the stator (35).

[0029] A pair of cylinders (20, 20') may be provided on both left and right ends of the above main casing (10).

[0030] The above pair of cylinders (20, 20') may be composed of a left cylinder (20) formed on the left side of the main casing (10) and a right cylinder (20') formed on the right side of the main casing (10).

[0031] As shown, the above pair of cylinders (20, 20') have an inner diameter smaller than the inner diameter of the main casing (10) and can be formed to extend in steps symmetrically from both ends of the main casing (10) to both sides.

[0032] Meanwhile, a pair of pistons (40, 40') having a thin cylindrical shape may be further provided on the left and right sides of the slider (30).

[0033] The above pair of pistons (40, 40') are formed to extend from the left and right ends of the slider (30) to both left and right sides as shown, and are installed so as to be able to slide and move inside the above pair of cylinders (20, 20').

[0034] Specifically, as illustrated, the pair of pistons (40, 40') may be composed of a left piston (40) formed to extend to the left from the left end of the slider (30), and a right piston (40') formed to extend to the right from the right end of the slider (30).

[0035] It is preferable that the pair of pistons (40, 40') have an outer diameter smaller than the outer diameter of the slider (30), and that the outer diameter size of the pair of pistons (40, 40') be formed to have a size smaller than the inner diameter size of the pair of cylinders (20, 20').

[0036] A shaft (32, 32') may be further provided between the slider (30) and the piston (40, 40'). The shaft (32, 32') is a connecting member for fixing the piston (40, 40') to the slider (30), and may be composed of a left shaft (32) provided between the slider (30) and the left piston (40), and a right shaft (32') provided between the slider (30) and the right piston (40').

[0037] The above shaft (32, 32') may be made entirely or partially of an insulating material to block the heat generated by the left-right linear movement of the slider (30) from being conducted to the piston (40, 40').

[0038] A stator (35) is provided on the outside of the slider (30). The stator (35) is preferably installed so as to have a diameter larger than the outer diameter of the slider (30) and to surround the outside of the slider (30).

[0039] The above stator (35) can force the slider (30) to move left and right by magnetic force.

[0040] Specifically, one of the slider (30) and the stator (35) is equipped with a permanent magnet in whole or in part, and the other is equipped with a conductive coil such as copper or a high temperature superconductor (HTS) coil to operate as an electromagnet. Accordingly, the polarity of the electromagnetic field between the slider (30) and the stator (35) periodically changes depending on changes in the voltage or frequency applied to the electromagnet, causing the slider (30) to move left and right.

[0041] At least one inlet (50, 50') and one outlet (60, 60') may be formed on the left or right sides of the pair of cylinders (20, 20') above. The inlet (50, 50') and outlet (60, 60') above serve as passages that guide the transport fluid (T) to flow into or out of the pump (1) according to the present invention.

[0042] Specifically, as shown, inlets (50, 50') are formed on the left and right sides of the pair of cylinders (20, 20'), respectively. The inlets (50, 50') can be divided into a left inlet (50) provided on the left side of the left cylinder (20), and a milk inlet (50') provided on the right side of the right cylinder (20').

[0043] The above discharge ports (60, 60') may be formed perpendicular to the above inlets (50, 50'), and are preferably formed at the ends of the left and right cylinders (20, 20') as shown. That is, the above discharge ports (60, 60') may be formed by a left discharge port (60) formed near the end (left end) of the left cylinder (20), and a right discharge port (60') formed near the end (right end) of the right cylinder (20').

[0044] Accordingly, the left outlet (60) and the right outlet (60') can be selectively opened and closed by the left and right cylinders (20, 20') according to the left and right movement of the slider (30).

[0045] In the present invention, for convenience, the fluid flowing by the pump (1) is referred to as the 'transport fluid (T)', and the fluid filled inside the main casing (10) is referred to as the 'filling fluid (C)'.

[0046] The transport fluid (T) flowing through the inlet (50, 50') and outlet (60, 60') may be composed of the same fluid as the filling fluid (C) filled inside the main casing (10).

[0047] In this way, if the filling fluid (C) and the transport fluid (T) are composed of the same fluid, no problem occurs even when the filling fluid (C) and the transport fluid (T) are mixed with each other, so there is no need to strictly maintain sealing between the cylinder (20, 20') and the piston (40, 40').

[0048] And the filling fluid (C) filled inside the main casing (10) can be configured to flow left and right of the slider (30). Accordingly, an orifice (34) that serves as a passage for the filling fluid (C) filled inside the main casing (10) can be formed through the slider (30) to pass through left and right.

[0049] As shown, the above orifices (34) can be formed in multiple numbers on the left and right sides of the slider (30) at equal intervals.

[0050] A vacuum case (70) spaced apart at a predetermined interval may be further provided on the outside of the main casing (10) and cylinder (20, 20').

[0051] The above vacuum case (70) may have a cylindrical shape with an outer diameter larger than the outer diameter of the main casing (10) and cylinder (20, 20') as shown, and may be formed in steps.

[0052] Accordingly, a predetermined space is formed between the vacuum case (70) and the main casing (10) and the cylinder (20, 20'). Since this space can be formed by vacuum, it is called a vacuum space (72). The vacuum space (72) prevents the main casing (10) and the cylinder (20, 20') from coming into direct contact with the outside air, thereby blocking heat transfer.

[0053] As shown, a stator casing (35') may be further provided in the central portion of the vacuum case (70). The stator casing (35') may serve to surround and protect the outer side of the stator (35).

[0054] The above main casing (10) may further be provided with a gas discharge port (80) that guides the discharge of gas inside the main casing (10).

[0055] As shown, the above gas discharge port (80) is connected to the flow space (12) formed inside the main casing (10), and serves as a passage for discharging the gas remaining inside the flow space (12) to the outside of the pump (1).

[0056] The above gas discharge port (80) may further be provided with an opening / closing valve (not shown) that opens / closes depending on the pressure inside the main casing (10). That is, when a large amount of gas accumulates inside the flow space (12) and the pressure rises above a certain set pressure, a valve that automatically opens to allow the gas to be discharged to the outside may be provided.

[0057] Meanwhile, one end of the main casing (10) may be further provided with a supplementary pipe (not shown) and a supplementary valve to supplement the filling fluid (C) inside the main casing (10) when it is insufficient.

[0058] In a pump (1) having such a configuration, when the slider (30) moves left and right by the stator (35), the transport fluid (T) introduced through the left and right inlets (50, 50') selectively flows through the left and right outlets (60, 60'), and as the slider (30) moves left and right, the filling fluid (C) inside the main casing (10) moves back and forth between the left space (12') and the right space (12") through the orifice (34), thereby ensuring smooth flow of the slider (30).

[0059] The scope of the present invention is not limited to the embodiments exemplified above, and many other modifications based on the present invention will be possible for those skilled in the art within the technical scope described above.

Claims

1. A cylindrical main casing (10) with a fluid space (12) formed inside; A slider (30) provided inside the main casing (10) and sliding inside the main casing (10); A pair of cylinders (20, 20') having an inner diameter smaller than the inner diameter of the main casing (10) and extending in steps symmetrically from both ends of the main casing (10) to both sides; A pair of pistons (40, 40') extending from both ends of the above slider (30) to both sides and slidingly moving inside the pair of cylinders (20, 20'); A stator (35) provided on the outside of the slider (30) and forcing the slider (30) to move by magnetic force; It has a configuration including an inlet (50, 50') and an outlet (60, 60') which are formed on one side of the above pair of cylinders (20, 20') and serve as an inlet and outlet passage for the transport fluid; A cryogenic pump characterized in that the transport fluid (T) flowing through the inlet (50, 50') and outlet (60, 60') is the same fluid as the filling fluid (C) filled inside the main casing (10).

2. In the first paragraph, the slider (30) has: A cryogenic pump characterized in that an orifice (34) is formed through the main casing (10) to serve as a passage for filling fluid (C) to be filled inside the main casing.

3. In the second paragraph, the orifice (34) is A cryogenic pump characterized in that a plurality of sliders (30) are formed at equal intervals.

4. In the third paragraph, in the main casing (10), A cryogenic pump characterized by further comprising a gas discharge port (80) for guiding the discharge of gas inside the main casing (10).

5. In the fourth paragraph, in the gas outlet (80), A cryogenic pump characterized in that it further comprises an opening / closing valve that opens / closes according to the pressure inside the main casing (10).

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