KR20220012153A - Reciprocal pump using linear motor - Google Patents

Abstract

The present invention relates to a cryogenic reciprocating pump using a linear motor. By adopting an electromagnetic type linear motor instead of a mechanical method such as a crank, the heat generated by pumping friction is minimized. By providing a structure that surrounds most of the linear motor with a vacuum layer, a cryogenic fluid to be pumped is isolated from the outside air, thereby blocking intrusion of heat into the cryogenic fluid. The reciprocating pump using a linear motor includes a cylinder assembly and a linear motor.

Description

Reciprocating pump using a linear motor {RECIPROCAL PUMP USING LINEAR MOTOR}

The present invention relates to a cryogenic reciprocating pump using a linear motor. By adopting an electromagnetic type linear motor instead of a mechanical method such as a crank, heat generation due to pumping friction is minimized, while most of the linear motor is surrounded by a vacuum layer. It relates to a cryogenic reciprocating pump that blocks heat penetration into the cryogenic fluid by isolating the cryogenic fluid to be pumped from the outside air by providing it.

Cryogenic pumps transport cryogenic fluids such as liquid or gaseous oxygen, nitrogen, argon, hydrocarbons and natural gas (LNG) under pressure.

Cryogenic pumps are increasingly used in industry. For example, a hydrogen vehicle stores high-pressure hydrogen in a storage tank and uses it as fuel, and receives hydrogen from a hydrogen charging station similar to a conventional gasoline and gasoline charging station.

The hydrogen filling station needs to be equipped with a cryogenic pump capable of generating a high pressure of, for example, 700 bar gauge or more, in order to move hydrogen from the central storage to the storage tank of the hydrogen vehicle. This is to compress as much hydrogen as possible according to the limited size of the storage tank and supply it to the storage tank, and when hydrogen is supplied at a high pressure of 700 bar gauge or more, it may be stored in the storage tank in the form of liquid or gas.

Cryogenic reciprocating pumps are used to store cryogenic fluids, particularly hydrogen or helium in liquid or gaseous state, into storage tanks. A conventional cryogenic reciprocating pump pumps a cryogenic fluid by horizontally reciprocating a piston using a mechanical crank drive. At this time, due to the characteristics of the mechanical method, frictional heat is generated during the driving process, and the generated heat is transferred to the fluid, thereby reducing the pumping efficiency.

In addition, the conventional cryogenic pump provides a structure surrounding the plunger part of the linear motor with a vacuum can in order to prevent the heat of the outside air at room temperature from being conducted to the fluid through the pump (thourgh).

However, a part of the fluid may flow into the sliding room through the gap between the piston and the plunger of the linear motor, but other parts other than the plunger part do not have a separate heat shielding means. You can't stop the heat from invading.

Korean Patent No. 10-1766010 discloses that the number of coils that are disposed on the outer periphery of the cylinder to generate a magnetic field are independently installed in the number corresponding to the length of the cylinder to generate an independent magnetic field, and the reciprocating distance and movement of the piston within the cylinder Disclosed is a reciprocating piston electromagnetic pump capable of freely controlling the speed.

However, Korea Patent Registration No. 10-1766010 does not shield the entire pump in a vacuum state like a conventional cryogenic pump, so it still has a disadvantage in that it cannot effectively block external heat intrusion.

Korea Patent No. 10-1766010 (2017.08.01, registered)

An object to be solved by one embodiment of the present invention is to provide a cryogenic reciprocating pump that prevents heat intrusion into a cryogenic fluid by minimizing frictional heat caused by pumping operation.

An object to be solved by one embodiment of the present invention is to provide a cryogenic reciprocating pump that fundamentally blocks heat conduction between the outside air and the cryogenic fluid despite the structural limitations of the linear motor.

Other objects of the present invention will become clearer through the examples described below.

The cryogenic reciprocating pump according to an embodiment of the present invention includes a cylinder 112 in which a piston 111 reciprocates linearly, an inlet 113 through which a fluid is sucked by reversing of the piston 111, A cylinder surrounding the outside of the cylinder 112 so that a vacuum gap VACCUM is formed in a space spaced apart from the first volleyball 114 from which the fluid pressurized by the advancement of the piston 111 is discharged, and the cylinder 112 . a cylinder assembly 110 including a jacket 116 and

A shaft 121 connected to the piston 111, a slider 122 that applies a linear driving force to the shaft 121, a stator 123 that forms an electromagnetic field with the slider 122, the shaft 121 and the slider A gas jacket 124 that surrounds the assembly of 122 and one end is closely coupled to the cylinder 112, and one end surrounds the outside of the gas jacket 124 while maintaining a vacuum gap with the gas jacket 124 The cylinder jacket 116 or the linear motor 120 including the gas jacket 125 closely coupled to the cylinder assembly 110 may be included.

In the reciprocating pump according to an embodiment of the present invention, an insulation supporter is disposed between the cylinder 112 and the cylinder jacket 116 and supports the cylinder 112 from a reaction force generated by pumping of the linear motor. (117) may be further included.

Here, the insulation supporter 117 has a cylindrical shape, and at least one ventilation hole may be formed on an outer circumferential surface.

The reciprocating pump according to an embodiment of the present invention may further include a second volleyball 115 for discharging unliquefied gas among the fluid pressurized by the forward movement of the piston 111 .

In addition, in the reciprocating pump according to an embodiment of the present invention, a multi-layered thin film insulation (MLI) layer may be further provided on the outside of the gas jacket 125 .

The slider 122 may be a permanent magnet, and the stator 123 may be an electromagnet made of either a copper coil or a superconducting coil. Alternatively, the slider 122 may be an electromagnet, and the stator 123 may be a permanent magnet.

At least a portion of the shaft 121 may be formed of an insulation material.

A cooling fan 127 may be further provided at one end of the stator frame 126 .

According to an embodiment of the present invention, by adopting an electromagnetic type linear motor instead of a mechanical method such as a crank, heat generation due to pumping friction can be minimized, thereby minimizing heat intrusion into the cryogenic fluid.

According to an embodiment of the present invention, heat intrusion into the cryogenic fluid can be fundamentally blocked by isolating the linear motor from outside air through a vacuum cap structure that surrounds most of the linear motor with a vacuum layer.

Effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a cross-sectional view showing the structure of a reciprocating pump according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a cylinder assembly part in the embodiment of FIG. 1 .
3 is a cross-sectional view illustrating a linear motor part in the embodiment of FIG. 1 .
4 is a perspective view of an insulation supporter according to an exemplary embodiment.
5 is a cross-sectional view illustrating in detail a structure of a vacuum layer of a reciprocating pump according to an embodiment.

Although the present invention can be interpreted and implemented in various embodiments, some representative embodiments will be described in detail with drawings for convenience of understanding. This is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In the accompanying drawings, even though they are shown in different drawings, the same reference numerals are given to the same components, and overlapping descriptions will be omitted.

1 is a cross-sectional view showing the structure of a reciprocating pump according to an embodiment of the present invention.

The cryogenic reciprocating pump of an embodiment is largely divided into a cylinder assembly 110 part and a linear motor 120 part. For convenience of understanding, the cylinder assembly 110 part and the linear motor 120 part are shown separately in FIGS. 2 and 3 , respectively.

FIG. 2 is a cross-sectional view illustrating a part of the cylinder assembly 110 in the reciprocating pump of FIG. 1 .

The cylinder assembly 110 may be defined as a tubular assembly structure in which a cryogenic fluid to be pumped is introduced, compressed by the linear motor 120 and discharged toward the storage tank.

Specifically, the cylinder assembly 110 includes a cylinder 112 , an inlet 113 , a first volleyball 114 , and a cylinder jacket 116 , and may further include a second volleyball 115 .

The cylinder 112 is also called a plunge (plunge) as a tubular structure in which the piston 111 of the linear motor linearly reciprocates therein.

The inlet 113 is a passage through which the cryogenic fluid is sucked by the backward movement of the piston 111 .

The first volleyball 114 is a passage through which the fluid pressurized by the forward movement of the piston 111 is discharged toward the storage tank, and the second volleyball 115 is among the cryogenic fluid pressurized by the forward movement of the piston 111 . It is a passage for discharging fluid that has not been liquefied due to external heat intrusion.

Most of the fluid introduced into the inlet 113 is compressed due to the pressure of the piston 111 and then moves to the storage tank through the first volley 114, but some are in a gaseous state without sufficient pressure for various reasons. is discharged to the second volleyball 115. The residual fluid discharged to the second volleyball 115 may be designed to re-introduce into the first volleyball 114 again.

The cylinder jacket 116 is spaced apart from the cylinder 112 and is a multi-stage diameter tubular structure implemented in a form to surround the outer circumference of the cylinder 112 . A closed space between the cylinder 112 and the cylinder jacket 116 is formed in a vacuum state by suction during the assembly process of the reciprocating pump. The closed space between the cylinder 112 and the cylinder jacket 116 may be referred to as a vacuum layer or a vacuum gap in this sense, and is denoted by 'VR1' in FIG. 1 . VR1 is interpreted as an abbreviation for Vaccum Room 1.

If the cylinder 112 is directly exposed to the outside air (Air), the relatively high heat of the outside air (Air) may invade the cryogenic fluid as it rides the metal cylinder 112 and conducts to the inside. The best pumping efficiency will come out when compression is applied while keeping the cryogenic temperature as it is, but thermal expansion occurs as the temperature of the fluid rises due to the inflow of outside heat, so more energy is consumed for pumping. Therefore, in one embodiment of the present invention, by blocking the cylinder 112 from the outside air with a vacuum gap of VR1, the first measures are taken to maintain the fluid at a cryogenic temperature.

3 is a cross-sectional view illustrating a linear motor part in the embodiment of FIG. 1 .

The linear motor 120 is a stator frame 126 for fixing the piston 111, the shaft 121, the slider 122, the stator 123, the gas jacket 125, the gas jacket 124, and the stator 123. Including, a cooling fan 127 for cooling the inside of the linear motor may be further included.

One end of the piston 111 is coupled to the slider 122 and the other end sucks or compresses the fluid by a pumping operation of horizontal movement. In order for the piston 111 to perform a smooth reciprocating linear motion within the cylinder 112 , a predetermined gap is required between the piston 111 and the cylinder 112 . However, a brush seal may be further provided on the outer peripheral surface of the piston 111 to prevent the fluid from flowing into the gap and flowing in the direction of the slider 122 .

The shaft 121 is a coupling member for fixing the piston 111 to the slider 122. In order to block the frictional heat generated by the linear movement of the slider 122 from being conducted to the piston 111, all or part of the shaft 121 is It is preferably made of an insulating material. As an insulating material, glass fiber reinforced plastics (Glass Fiber Reinforced Plastics, GFRP), fiber reinforced polyurethane (Reinforced Polyurethane Foam, RPUF) or rigid urethane (Polyurethane, PUR or Polyisocyanurate, PIR) may be used. However, this is only an example, and any material providing an insulating function may be used as the insulating material of the present invention.

Any one of the slider 122 and the stator 123 is equipped with a permanent magnet in all or part of it, and the other is equipped with a conductive coil such as copper or a high temperature superconductor (HTS) coil. It works with an electromagnet. Accordingly, the polarity of the electromagnetic field between the slider 122 and the stator 123 is periodically changed according to a change in voltage or frequency applied to the electromagnet, and the slider 122 moves forward or backward.

When the gas jacket 124 defines a sliding room as a sliding room, a combination of the shaft 121 and the slider 122 or a space in which the slider 122 moves is a can-shaped support with one open side surrounding the sliding room. is absent One end of the open surface of the gas jacket 124 is closely coupled to the cylinder 112 .

The vacuum jacket 125 is a can-shaped support member with one open side that surrounds the outside of the gas jacket 124 while maintaining a gap with the gas jacket 124 . One end of the open surface of the vacuum jacket 125 is closely coupled to the cylinder jacket 116 or a part of the cylinder assembly 110 .

Some of the fluid compressed due to the pressurization of the linear motor 120 passes through the gap between the piston 111 and the cylinder 112 of the linear motor, not the first volleyball 114 and the second volleyball 115 . It may also be introduced into the cold part of the

The atmosphere inside and outside the pump (that is, outside air or air) is usually at room temperature, and thus has a relatively higher temperature than the low temperature part or the sliding room. Accordingly, a vacuum gap (VR2) between the gas jacket 124 and the vacuum jacket 125 blocks the low temperature part of the linear motor from the outside air, thereby preventing the relatively high temperature heat of the outside air from penetrating into the linear motor.

As a result, the piston 111 moving part (or cylinder jacket part) of the linear motor is blocked from outside air by the vacuum layer of VR1, and the slider 122 moving part (or sliding room part) of the linear motor is in the vacuum layer of VR2. blocked from the outside air by

On the other hand, the reciprocating pump according to another embodiment of the present invention is disposed between the cylinder 112 and the cylinder jacket 116 and supports the cylinder 112 from the reaction force generated by the pumping of the linear motor. It may further include an insulation supporter 117 that does.

4 is a perspective view illustrating a shape of the insulation supporter 117 according to an embodiment, and FIG. 5 is a cross-sectional view illustrating a structure of a vacuum layer of a reciprocating pump according to an embodiment in detail.

In the example of FIG. 4 , the insulation supporter 117 has a cylindrical shape or a ring shape, and at least one ventilation hole may be further formed on an outer circumferential surface. Through the vent(s), VR1 and VR2 form a single vacuum layer connected to each other.

As another embodiment of the insulation supporter 117, it may have a cylindrical shape or a ring shape, but a separate ventilation hole may not be formed. In this case, VR1 and VR2 form separate separate vacuum layers. In addition, although not shown in the accompanying drawings, in the embodiment of the reciprocating pump in which the insulation supporter 117 is not provided, the vertical portion of the cylinder jacket 112 and the vertical portion of the cylinder 116 are directly and closely coupled to each other without the insulation supporter Also, in this case, VR1 and VR2 form a separate vacuum layer.

In addition, in the reciprocating pump according to another embodiment of the present invention, a multi-layer insulation (MLI) layer (not shown) may be further provided on some or all of the outer surface of the gas jacket 125 . . For example, in the multi-layer thin film insulation material, each layer may be formed of a plastic material such as Mylar or Kapton, and a metal film may be coated thereon. Due to the multi-layered thin film insulating material layer, it blocks the intrusion of external radiant heat into the linear motor.

Although the embodiments of the present invention have been described above with reference to the drawings, those of ordinary skill in the art may change the present invention in various ways within the scope not departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that modifications and variations are possible.

110: cylinder assembly
111: piston 112: cylinder
113: inlet 114: first volleyball
115: second volleyball 116: cylinder jacket
117: insulation supporter
120: linear motor
121: shaft 122: slider
123: stator 124: gas jacket
125: vacuum jacket 126: stator frame
127: cooling fan

Claims (10)

The cylinder 112 in which the piston 111 reciprocates linearly, the inlet 113 through which the fluid is sucked by the backward movement of the piston 111, and the fluid pressurized by the forward movement of the piston 111 is discharged. A cylinder assembly 110 including a first volleyball 114, a cylinder jacket 116 surrounding the outside of the cylinder 112 so that a vacuum gap (VACCUM) is formed in a space spaced apart from the cylinder 112; and
A shaft 121 connected to the piston 111, a slider 122 that applies a linear driving force to the shaft 121, a stator 123 that forms an electromagnetic field with the slider 122, the shaft 121 and the slider A gas jacket 124 enclosing the assembly of 122 and having one end closely coupled to the cylinder 112, while maintaining a vacuum gap with the gas jacket 124, enclosing the outside of the gas jacket 124 and having one end A linear motor 120 including a gas jacket 125 closely coupled to the cylinder jacket 116 or the cylinder assembly 110 .
A reciprocating pump using a linear motor comprising a. According to claim 1,
It is disposed between the cylinder 112 and the cylinder jacket 116 and further comprises an insulation supporter 117 for supporting the cylinder 112 from a reaction force generated by pumping of the linear motor.
Reciprocating pump using a linear motor. 3. The method of claim 2,
The insulation supporter 117 has a cylindrical shape, characterized in that at least one ventilation hole is formed on the outer peripheral surface
Reciprocating pump using a linear motor. 3. The method of claim 2,
Characterized in that it further comprises a second volleyball (115) for discharging the non-liquefied gas among the fluid pressurized by the advancement of the piston (111).
Reciprocating pump using a linear motor. According to claim 1,
A multi-layer insulation (MLI) layer is further provided on the outside of the gas jacket 125.
Reciprocating pump using a linear motor. According to claim 1,
The slider (122) is a permanent magnet (magnet), characterized in that the stator (123) is an electromagnet
Reciprocating pump using a linear motor. 7. The method of claim 6,
The stator 123 is an electromagnet made of either a copper coil or a superconducting coil.
Reciprocating pump using a linear motor. According to claim 1,
The slider (122) is an electromagnet, and the stator (123) is a permanent magnet (magnet), characterized in that
Reciprocating pump using a linear motor. According to claim 1,
At least a portion of the shaft 121 is characterized in that made of an insulation material
Reciprocating pump using a linear motor. According to claim 1,
A cooling fan 127 is further provided at one end of the stator frame 126
Reciprocating pump using a linear motor.

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