JP2017020440A - Liquefied gas injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of a seal part of a plunger pump, in a liquefied gas injection device.SOLUTION: A liquefied gas injection device includes: a heat exchanger configured to cool liquefied gas for injection as liquefied gas whose temperature is increased by pressure rise, by heat exchange between the above liquefied gas and liquefied gas for cooling as liquefied gas used as refrigerant; and a plunger pump having a seal part installed at an opening for taking in/out a plunger, at a cylinder end part, and configured to increase pressure of liquefied gas for injection, wherein the liquefied gas injection device includes a plunger cover connected to the cylinder end part and surrounding a part of the plunger, and exhaust supply means for supplying into the plunger cover exhaust from the heat exchanger containing vaporized liquefied gas for cooling.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquefied gas injection device.

  For example, there has been proposed a liquefied gas injection device that cleans an object to be cleaned by injecting the object to be cleaned with a low-temperature and high-pressure liquefied gas such as liquefied nitrogen gas (liquid nitrogen) or liquefied carbon dioxide gas (liquefied carbon dioxide). Yes. The liquefied gas injection device can remove deposits such as dirt attached to the surface of the object to be cleaned without damaging the surface of the object to be cleaned. Further, since the liquefied gas is vaporized after the injection, it does not remain on the surface of the object to be cleaned after the treatment. Patent Document 1 discloses a liquefied gas injection device that pressurizes and injects liquefied gas with a plunger pump.

US Pat. No. 7,310,955

  By the way, the plunger pump used in the liquefied gas injection device is provided with a seal portion so that the liquefied gas does not leak into the sliding portion between the plunger and the cylinder. In general, a hydraulic cylinder is used to drive the plunger pump, and the seal portion is heated by heat radiation from the hydraulic cylinder and friction with the plunger, and is cooled by contacting with the liquefied gas. For this reason, the seal portion is easily deteriorated due to a temperature difference, and a replacement operation or the like in a short time is required.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress deterioration of a seal portion of a plunger pump in a liquefied gas injection device.

  In order to achieve the above object, in the present invention, as a first solving means, heat exchange with a liquefied gas for cooling, which is a liquefied gas used as a refrigerant, is a liquefied gas that is liquefied gas that has been heated by pressure increase. A liquefied gas injection apparatus comprising: a heat exchanger that cools by a gas pump; and a plunger pump that has a seal portion installed at a plunger inlet / outlet opening at a cylinder end and pressurizes the liquefied gas for injection. A plunger cover that is connected and encloses a part of the plunger; and an exhaust supply means that supplies exhaust gas from the heat exchanger including the vaporized liquefied liquefied gas to the inside of the plunger cover. adopt.

  As the second solving means, the first solving means is provided with a cooling jacket disposed around the seal portion, and the exhaust supply means supplies the exhaust to the cooling jacket. To do.

  As a third solution, in the first or second solution, the heat exchanger is a spare installed in a pre-boosting unit that pre-pressurizes the liquefied gas for injection before being supplied to the plunger pump. A means is adopted that includes a heat exchanger for pressurization and a chiller that adjusts the temperature of the liquefied gas for injection that has been pressurized by the plunger pump.

  As a fourth solution means, in the third solution means, a liquid supply pipe for guiding the cooling liquefied gas from the preliminary pressure raising unit to the chiller is provided, and the exhaust supply means includes the liquid supply pipe therein. A means is provided that is provided with an exhaust pipe for liquid supply pipe that is inserted and guides the exhaust.

  As a fifth means, in the third or fourth solution means described above, an injection pipe for guiding the liquefied gas for injection from the chiller to the injection section is provided, and the exhaust supply means has the injection pipe inserted therein. And a means for providing an exhaust pipe for an injection pipe for guiding the exhaust.

  As a sixth means, the means in any one of the first to fifth solving means is provided with a servo motor for driving the plunger pump.

  According to the present invention, the exhaust from the heat exchanger containing the vaporized liquefied gas is supplied into the plunger cover connected to the cylinder end where the seal portion is installed. For this reason, the temperature rise of the seal portion is suppressed, and the change in the temperature of the seal portion becomes small. Therefore, according to the present invention, deterioration of the seal portion of the plunger pump can be suppressed in the liquefied gas injection device.

It is a flowchart which shows the apparatus structure of the liquefied gas injection apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of the pressure | voltage rise part with which the liquefied gas injection apparatus which concerns on one Embodiment of this invention is provided. It is a schematic diagram which shows the control system of the liquefied gas injection apparatus which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the pressure of a plunger pump with which the liquefied gas injection device which concerns on one Embodiment of this invention is provided, and time.

Hereinafter, an embodiment of a liquefied gas injection device 1 according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a liquefied gas injection device 1 of the present embodiment. In FIG. 1, components that are not directly related to the characteristic points of the liquefied gas injection device according to the present embodiment, such as various pipes and valves, are omitted for convenience.

  The liquefied gas injection device 1 of the present embodiment is a device that uses, for example, liquid nitrogen as the liquefied gas, and injects the liquefied gas after increasing the pressure. As shown in FIG. 1, the liquefied gas injection device 1 includes a liquefied gas supply unit 10, a preliminary pressure increase unit 20, a pressure increase unit 30, a chiller 40 (heat exchanger), an injection unit 50, and an exhaust supply unit 60. (Exhaust supply means) and a controller 70 (see FIG. 3).

  The liquefied gas supply unit 10 is a tank that supplies the liquefied gas X1, and is connected to the preliminary pressure increasing unit 20 via the pipe p1. The liquefied gas X1 supplied from the liquefied gas supply unit 10 to the preliminary boosting unit 20 is supplied to the preliminary boosting unit 20 as the liquefied gas X2 for injection and the liquefied gas X3 (refrigerant) for cooling. The liquefied gas X2 for injection is the liquefied gas X1 used for the purpose of injection. The liquefied gas X3 for cooling is the liquefied gas X1 used for cooling the liquefied gas X2 for injection. In addition, the pre-boosting unit 20 and the chiller 40 are connected by a pipe p5 described later, and a part of the cooling liquefied gas X3 is supplied to the chiller 40. That is, the liquefied gas supply unit 10 supplies the liquefied gas X3 for cooling to the chiller 40 through the preliminary pressure increasing unit 20 and the pipe p5.

  The preliminary boosting unit 20 preliminarily boosts the liquefied gas X2 for injection before being supplied to the boosting unit 30, and includes a preliminary boosting heat exchanger 21, a preliminary boosting pump 22, and a circulation pump (not shown). I have. The pre-pressurization heat exchanger 21 is a heat exchanger that cools the injection liquefied gas X2 supplied from the liquefied gas supply unit 10 by heat exchange with the cooling liquefied gas X3, and is preliminarily boosted by an internal pipe (not shown). Connected to the pump. The preliminary boosting pump 22 is a pump that preliminarily boosts the liquefied gas X1. The preliminary booster pump 22 is connected to the booster 30 by a pipe p2. In such a pre-pressurization unit 20, while the liquefied gas X <b> 2 for injection is circulated by a circulation pump, the pre-pressurization pump 22 increases the pressure and cools by the pre-pressurization heat exchanger 21.

  The booster 30 is a device that further boosts the preliminarily boosted liquefied gas X2 for injection. As shown in FIG. 2 and FIG. 3 in addition to FIG. 1, the booster 30 includes two plunger pumps 31 and two pump driving units 32. The plunger pump 31 is supplied with the liquefied gas X2 for injection through the pipe p21 and the pipe p22 branched from the pipe p2. Also, the liquefied gas X2 for injection boosted by the plunger pump 31 is sent to the chiller 40 via the pipes p31 and p32 connected to the plunger pump 31 and the pipe p3 in which these pipes p31 and p32 are aggregated. Sent.

  Then, with reference to FIG. 2, the more detailed structure of the plunger pump 31 and the pump drive part 32 is demonstrated. Each plunger pump 31 has two cylinders (cylinder 3a and cylinder 3b) and one plunger 3c having an end inserted into these cylinders. The plunger pump 31 includes a seal portion 3d, a plunger cover 3e, and a cooling jacket 3f.

  The cylinder 3a and the cylinder 3b are disposed at the end of the plunger pump 31, respectively. The cylinder 3a and the cylinder 3b are cylindrical members to which the liquefied gas X2 for injection preliminarily pressurized by the preliminary pressure increasing unit 20 is supplied. These cylinders 3a and 3b have plunger inlet / outlet openings at the end portions through which the plunger 3c is taken in and out. The plunger 3c is a rod member having one end 3c1 side inserted into the cylinder 3a and the other end 3c2 side inserted into the cylinder 3b. The plunger 3c is reciprocated in the direction along the axis by the pump drive unit 32 to increase the pressure of the liquefied gas X2 for injection inside the cylinder 3a and the cylinder 3b.

  In the following description, the cylinder 3a of one plunger pump 31 is referred to as cylinder A, and the cylinder 3b of the same plunger pump 31 is referred to as cylinder B as necessary. The cylinder 3a of the other plunger pump 31 is referred to as cylinder C, and the cylinder 3b of the same plunger pump 31 is referred to as cylinder D.

  The seal portion 3d is embedded in the end portion of the cylinder 3a and the cylinder 3b where the plunger inlet / outlet opening is formed. The seal portion 3d is a contact-type seal portion for preventing the liquefied gas X2 for injection from leaking from the plunger inlet / outlet opening. Such a seal portion 3d is formed in an annular shape so as to surround the plunger 3c, and the inner peripheral surface is slid with the plunger 3c.

  The plunger cover 3e is connected to each of the end portions (cylinder end portions) of the cylinder 3a and the cylinder 3b in which the plunger inlet / outlet opening is formed, and covers a part of the plunger 3c outside the cylinder 3a and the cylinder 3b. The plunger cover 3e has no wall surface on the cylinder 3a and cylinder 3b side. For this reason, the seal | sticker part 3d provided in the edge part of the cylinder 3a and the cylinder 3b is exposed inside the plunger cover 3e. In this embodiment, the plunger cover 3e is connected to a later-described fifth pipe 65 of the exhaust supply unit 60, and an exhaust X4 described later is supplied from the exhaust supply unit 60 into the plunger cover 3e.

  3 f of cooling jackets are arrange | positioned at the edge part of the cylinder 3a and the cylinder 3b so that the seal | sticker part 3d may be covered from a radial direction outer side. The cooling jacket 3 f is an annular pipe line installed around the seal portion 3 d and is connected to a later-described fifth pipe 65 of the exhaust supply unit 60. The cooling jacket 3f cools the seal portion 3d by supplying exhaust X4 (described later) from the exhaust supply portion 60 to the inside.

  The pump drive unit 32 includes a servo motor 32a, a drive gear 32b, a driven gear 32c, a screw shaft 32d, and a nut 32e. The servo motor 32a is connected to an external power source or the like, and generates rotational power under the control of the controller 70 (see FIG. 3). The drive gear 32b is fixed to the output shaft of the servo motor 32a and is driven to rotate by the servo motor 32a. The driven gear 32c is meshed with the drive gear 32b, and is driven to rotate when the drive gear 32b is rotationally driven. The screw shaft 32d is fixed to the driven gear 32c, and is rotated when the driven gear 32c is rotationally driven. The screw shaft 32d is disposed so that the shaft core is parallel to the plunger 3c. The nut 32e is screwed with the screw shaft 32d, and is moved in a direction along the axis of the screw shaft 32d when the screw shaft 32d rotates. The nut 32e is fixed to the plunger 3c. For this reason, the plunger 3c is moved in the direction along the axis of the screw shaft 32d (that is, the direction along the axis of the plunger 3c) by moving the nut 32e along the axis of the screw shaft 32d.

  In such a booster 30, rotational power is generated by the servo motor 32a of the pump drive unit 32, and this rotational power is transmitted to the plunger 3c via the drive gear 32b, the driven gear 32c, the screw shaft 32d, and the nut 32e, As a result, the plunger 3c is driven.

  The rotation direction of the servo motor 32a is changed by the controller 70 at a constant cycle. For this reason, the plunger 3c repeats reciprocation at a constant period. As a result, the liquefied gas X2 for injection is boosted in order in the cylinder 3a and the cylinder 3b.

  Returning to FIG. 1, the chiller 40 is connected to the booster 30 via the pipe p <b> 3. Further, the chiller 40 is connected to the preliminary boosting unit 20 through the pipe p5. The pipe p5 is a liquid feeding pipe for guiding the cooling liquefied gas X3 from the preliminary pressure increasing unit 20 to the chiller 40. The chiller 40 exchanges heat between the liquefied gas X2 for injection supplied from the pressure booster 30 through the pipe p3 and the liquefied gas X3 for cooling supplied from the preliminary pressure booster 20 through the pipe p5, thereby liquefying gas X2 for injection. It is a heat exchanger which adjusts the temperature.

  The injection unit 50 is connected to the chiller 40 via the pipe p4. The pipe p4 is an injection pipe that guides the liquefied gas X2 for injection from the chiller 40 to the injection unit 50. The injection unit 50 injects the liquefied gas for injection X2 supplied via the pipe p4 toward the object to be cleaned.

  The exhaust supply unit 60 includes a first pipe 61 connected to the pre-pressurization heat exchanger 21, a second pipe 62 connected to the chiller 40, a third pipe 63 (exhaust pipe for liquid supply pipe) surrounding the pipe p5, A fourth pipe 64 (injection pipe exhaust pipe) surrounding the pipe p4 and a fifth pipe 65 connected to the plunger pump are provided. One end of the first pipe 61 is connected to the pre-pressurization heat exchanger 21 of the pre-pressurization unit 20, and the other end is connected to the end of the third pipe 63 on the chiller 40 side. The first pipe 61 guides the exhaust X4 containing the cooling liquefied gas X3 vaporized by heat exchange in the preliminary pressurizing heat exchanger 21 from the preliminary pressurizing unit 20 to the third pipe 63. The second pipe 62 has one end connected to the chiller 40 and the other end connected to the end of the fourth pipe 64 on the injection unit 50 side. The second pipe 62 guides the exhaust X4 containing the cooling liquefied gas X3 vaporized by heat exchange in the chiller 40 from the chiller 40 to the fourth pipe 64.

  The third pipe 63 is a pipe through which the pipe p <b> 5 is inserted, and is arranged between the preliminary booster 20 and the chiller 40. That is, a double pipe formed by the pipe p5 and the third pipe 63 is disposed between the preliminary boosting unit 20 and the chiller 40. The third pipe 63 is connected to the fifth pipe 65 and guides the exhaust X4 to the fifth pipe 65 while flowing the exhaust X4 around the pipe p5. The fourth pipe 64 is a pipe through which the pipe p <b> 4 is inserted, and is arranged between the chiller 40 and the injection unit 50. That is, a double pipe formed by the pipe p4 and the fourth pipe 64 is disposed between the chiller 40 and the injection unit 50. The fourth pipe 64 is connected to the fifth pipe 65 and guides the exhaust X4 to the fifth pipe 65 while flowing the exhaust X4 around the pipe p4.

  The fifth pipe 65 is connected to the plunger cover 3e and the cooling jacket 3f of the pressure increasing unit 30, and the fifth pipe 65 supplies the exhaust X4 supplied from the third pipe 63 and the fourth pipe 64 to the plunger cover 3e. And the inside of the cooling jacket 3f.

  Next, a control system of the liquefied gas injection device 1 will be described with reference to FIG. As shown in FIG. 3, the liquefied gas injection device 1 includes a controller 70 and a plurality of pressure gauges 71. The controller 70 is connected to the pressure gauge 71 and the servo motor 32a, and controls the servo motor 32a while confirming the detection signal of the pressure gauge 71. The pressure gauge 71 is installed in a pipe p31 connected to the cylinders A and C, a pipe p32 connected to the cylinders B and D, and a pipe p3 that is a collective pipe of the pipes p31 and p32. Yes.

  Here, as shown in FIG. 4, the controller 70 controls the servo motor 32a so that the pressure increase timings of the cylinders A to D are displaced for a certain period so that the pressure in the pipe p3 is always constant. Specifically, the controller 70 controls the booster 30 so that the reciprocating cycle of the plunger 3c of one plunger pump 31 and the reciprocating cycle of the plunger 3c of the other plunger pump 31 are shifted by a quarter cycle.

  In the liquefied gas injection device 1 of the present embodiment having such a configuration, the liquefied gas X1 supplied from the liquefied gas supply unit 10 to the preliminary boosting unit 20 as the liquefied gas X2 for injection is combined with the liquefied gas X3 for cooling. Pre-pressurization is performed while cooling by heat exchange. The preliminarily boosted injection liquefied gas X2 is further boosted by the booster 30 and is temperature-adjusted by the chiller 40 by heat exchange with the cooling liquefied gas X3 and then injected from the injector 50.

  Here, according to the liquefied gas injection device 1 of the present embodiment, the vaporized liquefied gas X1 is contained inside the cylinder cover 3e where the seal portion 3d is installed and the plunger cover 3e connected to the end of the cylinder 3b. Exhaust gas X4 from the heat exchanger (preliminary pressurizing heat exchanger 21 and chiller 40) is supplied. For this reason, the temperature rise of the seal part 3d is suppressed, and the temperature change of the seal part 3d becomes small. Therefore, according to the liquefied gas injection device 1 of the present embodiment, deterioration of the seal portion 3d can be suppressed.

  Further, the liquefied gas injection device 1 of the present embodiment includes a cooling jacket 3f disposed around the seal portion 3d, and the exhaust X4 is supplied from the exhaust supply portion 60 to the cooling jacket 3f. For this reason, the temperature rise of the seal portion 3d can be further suppressed, and the deterioration of the seal portion 3d can be further suppressed.

  Moreover, in the liquefied gas injection apparatus 1 of this embodiment, the heat exchanger 21 for preliminary pressure | voltage rises and the chiller 40 are provided as a heat exchanger. Therefore, the exhaust X4 can be obtained from the preliminary pressurizing heat exchanger 21 and the chiller 40, and the exhaust X4 having a sufficient flow rate can be supplied to the boosting unit 30.

  Further, in the liquefied gas injection device 1 of the present embodiment, the exhaust gas supply unit 60 includes a third pipe 63 that surrounds the pipe p5 and a fourth pipe 64 that surrounds the pipe p4. For this reason, it becomes possible to suppress the heat absorption of the cooling liquefied gas X3 in the pipe p4 and the heat absorption of the jet liquefied gas X2 in the pipe p5.

  Further, in the liquefied gas injection device 1 of the present embodiment, the plunger pump 31 is driven using the servo motor 32a as a power source. For this reason, compared with the case where a hydraulic mechanism is used, the calorie | heat amount generate | occur | produced from a motive power source can be suppressed and the temperature rise of the seal | sticker part 3d can be suppressed. Further, since the heat generation amount of the power source is small, the servo motor 32a as the power source can be disposed close to the seal portion 3d, and the liquefied gas injection device 1 can be miniaturized.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, the booster 30 has the two plunger pumps 31. However, the present invention is not limited to this, and it is possible to employ a configuration in which the pressure increasing unit 30 includes one plunger pump 31 or three or more plunger pumps 31.

(2) In the above embodiment, the cooling jacket 3f, the third pipe 63 surrounding the pipe p5, and the fourth pipe 64 surrounding the pipe p4 are provided. However, it is also possible to adopt a configuration in which any or all of these are omitted.

(3) In the above embodiment, the plunger pump 31 is driven by the power of the servo motor 32a. However, the present invention is not limited to this, and the driving method of the plunger pump 31 may be a driving by a hydraulic pump, a driving by another mechanical device, or an electric driving other than the servo motor 32a.

DESCRIPTION OF SYMBOLS 1 Liquefied gas injection apparatus 3a Cylinder 3b Cylinder 3c Plunger 3c1 One end 3c2 The other end 3d Seal part 3e Plunger cover 3f Cooling jacket 10 Liquefied gas supply part 20 Preliminary pressure booster 21 Preliminary pressure booster heat exchanger 22 Preliminary pressure booster pump 30 Pressure booster 31 Plunger Pump 32 Pump drive part 32a Servo motor 32b Drive gear 32c Driven gear 32d Screw shaft 32e Nut 40 Chiller 50 Injection part 60 Exhaust supply part (exhaust supply means)
61 1st piping 62 2nd piping 63 3rd piping (exhaust pipe for liquid feeding pipe)
64 4th piping (exhaust pipe for injection pipe)
65 Fifth pipe 70 Controller 71 Pressure gauge A Cylinder B Cylinder D Cylinder D Cylinder p1 Piping p2 Piping p21 Piping p22 Piping p3 Piping p31 Piping p32 Piping p4 Piping (Injection pipe)
p5 Piping (liquid feeding pipe)
X1 liquefied gas X2 jet liquefied gas X3 cooling liquefied gas X4 exhaust

Claims (6)

A heat exchanger that cools the liquefied gas for injection, which is a liquefied gas heated by the pressure increase, by heat exchange with a liquefied gas for cooling that is a liquefied gas used as a refrigerant;
A liquefied gas injection device having a seal portion installed at a plunger inlet / outlet opening at a cylinder end and a plunger pump for boosting the liquefied gas for injection,
A plunger cover connected to the cylinder end and enclosing a portion of the plunger;
An exhaust gas supply unit that supplies exhaust gas from the heat exchanger containing the vaporized cooling liquefied gas to the inside of the plunger cover. A cooling jacket disposed around the seal portion;
The liquefied gas injection device according to claim 1, wherein the exhaust gas supply unit supplies the exhaust gas to the cooling jacket.   As the heat exchanger, a pre-pressurization heat exchanger installed in a pre-pressurization unit that pre-pressurizes the liquefied gas for injection before being supplied to the plunger pump, and the liquefaction for injection pressurized by the plunger pump The liquefied gas injection device according to claim 1, further comprising a chiller that adjusts the temperature of the gas. A liquid feed pipe for guiding the cooling liquefied gas from the preliminary pressure raising unit to the chiller;
The liquefied gas injection device according to claim 3, wherein the exhaust supply unit includes a liquid supply pipe exhaust pipe through which the liquid supply pipe is inserted and guides the exhaust. An injection pipe for guiding the liquefied gas for injection from the chiller to the injection unit;
5. The liquefied gas injection device according to claim 3, wherein the exhaust supply unit includes an exhaust pipe for an injection pipe through which the injection pipe is inserted and guides the exhaust. The liquefied gas injection device according to claim 1, further comprising a servo motor that drives the plunger pump.

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