JP6515713B2 - Liquefied gas injection system - Google Patents

Description

  The present invention relates to a liquefied gas injection device.

  For example, a liquefied gas injection device is proposed that cleans the object to be cleaned by injecting a liquefied gas at low temperature and high pressure such as liquefied nitrogen gas (liquid nitrogen) or liquefied carbon dioxide gas (liquefied carbon dioxide) onto the object to be cleaned. There is. The liquefied gas injection device can remove deposits such as dirt adhering 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 which pressurizes liquefied gas by a plunger pump and injects the liquefied gas.

U.S. Pat. No. 7,310,955

  By the way, the plunger pump used for a liquefied gas injection device is provided with a seal part in order not to leak liquefied gas to the sliding part of a plunger and a cylinder. A hydraulic cylinder is generally used to drive the plunger pump, and the seal portion is heated by heat dissipation from the hydraulic cylinder and friction with the plunger, and is cooled by contact with liquefied gas. For this reason, the seal portion is easily deteriorated due to the temperature difference, and replacement work 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 of the present invention 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, according to the present invention, as a first solution, heat exchange with a liquefied gas for cooling, which is a liquefied gas that uses liquefied gas for injection that is liquefied gas heated by pressure increase, as a refrigerant A liquefied gas injection device comprising: a heat exchanger for cooling by the heat exchanger; a seal portion installed at a plunger inlet / outlet opening of a cylinder end; and a plunger pump for pressurizing the liquefied gas for injection; A plunger cover connected and surrounding a portion of the plunger, and exhaust supply means for supplying the exhaust from the heat exchanger containing the vaporized liquefied gas for cooling to the inside of the plunger cover; adopt.

  As a second solution means, in the first solution means, there is provided a cooling jacket disposed around the seal portion, and the exhaust gas supply means adopts means for supplying the exhaust gas also to the cooling jacket. Do.

  As a third solution means, in the first or second solution means, as the heat exchanger, a spare pressure-rising unit installed in a preliminary pressure-boosting portion for preliminarily pressure-raising the liquefied gas for injection before being supplied to the plunger pump. A means is provided that includes a pressure raising heat exchanger and a chiller that adjusts the temperature of the liquefied gas for injection pressurized by the plunger pump.

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

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

  As a sixth means, in any one of the above first to fifth solutions, a means is provided which comprises a servomotor for driving the plunger pump.

  According to the present invention, the exhaust from the heat exchanger containing the vaporized liquefied gas is supplied to the inside of 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 is reduced. Therefore, according to the present invention, in the liquefied gas injection device, deterioration of the seal portion of the plunger pump can be suppressed.

It is a flow figure showing the apparatus configuration of the liquefied gas injection device concerning one embodiment of the present invention. It is a schematic diagram of a pressure rising part with which the liquefied gas injection device concerning one embodiment of the present 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 of the pressure of the plunger pump with which the liquefied gas injection device concerning one embodiment of the present invention is equipped, 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 feature of the liquefied gas injection device according to the present embodiment, for example, 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 pressurizes and injects the liquefied gas. 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 gas 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 a pipe p1. The liquefied gas X1 supplied from the liquefied gas supply unit 10 to the preliminary pressurizing unit 20 is supplied to the preliminary pressurizing unit 20 as the liquefied gas for injection X2 and the liquefied gas for cooling X3 (refrigerant). In addition, the liquefied gas X2 for injection is liquefied gas X1 used for the use of injection. Moreover, the liquefied gas X3 for cooling is liquefied gas X1 used for the use of cooling of liquefied gas X2 for injection. Moreover, the preliminary | backup pressurizing part 20 and the chiller 40 are connected by the below-mentioned piping p5, and a part of liquefied gas X3 for cooling is supplied to the chiller 40. As shown in FIG. That is, the liquefied gas supply unit 10 supplies the cooling liquefied gas X3 to the chiller 40 through the preliminary pressurizing unit 20 and the pipe p5.

  The preliminary pressure-boosting section 20 preliminarily pressure-boosts the liquefied gas for injection X2 before being supplied to the pressure-boosting section 30, and comprises a preliminary pressure-boosting heat exchanger 21, a preliminary pressure-boosting pump 22, and a circulation pump (not shown). Have. The preliminary pressurizing heat exchanger 21 is a heat exchanger for cooling the liquefied gas for injection X2 supplied from the liquefied gas supply unit 10 by heat exchange with the liquefied gas for cooling X3, and the preliminary pressurization is performed by an internal pipe (not shown). Connected to the pump. The pre-boost pump 22 is a pump that pre-boosts the liquefied gas X1. The preliminary booster pump 22 is connected to the booster 30 by a pipe p2. In such a preliminary pressure-boosting unit 20, while the liquefied gas for injection X2 is circulated by the circulation pump, the pressure is raised by the preliminary pressure-boosting pump 22 and is cooled by the heat exchanger 21 for preliminary pressure-boosting.

  The booster unit 30 is a device that further boosts the pre-boosted liquefied gas for injection X2. As shown in FIGS. 2 and 3 in addition to FIG. 1, the pressure booster 30 includes two plunger pumps 31 and two pump drivers 32. The injection liquefied gas X2 is supplied to the plunger pump 31 via a pipe p21 and a pipe p22 branched from the pipe p2. Further, the liquefied gas for injection X2 boosted by the plunger pump 31 is supplied to the chiller 40 through the pipe p31 and the pipe p32 connected to the plunger pump 31, and the pipe p3 in which the pipe p31 and the pipe p32 are integrated. Will be sent.

  Subsequently, more detailed configurations of the plunger pump 31 and the pump drive unit 32 will be described with reference to FIG. Each plunger pump 31 has two cylinders (a cylinder 3a and a cylinder 3b) and one plunger 3c whose end is inserted into these cylinders. Further, the plunger pump 31 includes a seal portion 3d, a plunger cover 3e, and a cooling jacket 3f.

  The cylinder 3 a and the cylinder 3 b are respectively disposed at the end of the plunger pump 31. The cylinder 3a and the cylinder 3b are cylindrical members to which the liquefied gas for injection X2 pre-boosted by the pre-pressure boosting unit 20 is supplied. The cylinder 3a and the cylinder 3b have a plunger in / out opening at the end, through which the plunger 3c is taken in and out. The plunger 3c is a rod member whose one end 3c1 side is inserted into the cylinder 3a and whose other end 3c2 side is inserted into the cylinder 3b. The plunger 3 c is reciprocated by the pump drive unit 32 in the direction along the axis to pressurize the injection liquefied gas X 2 in the cylinder 3 a and the cylinder 3 b.

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

  The seal portion 3d is embedded at an end of the cylinder 3a and the cylinder 3b where the plunger entry and exit openings are formed. The seal portion 3d is a contact type seal portion for preventing leakage of the liquid gas for injection X2 from the plunger inlet / outlet opening. Such a seal portion 3d is annular so as to surround the plunger 3c, and the inner peripheral surface thereof is slid with the plunger 3c.

  The plunger cover 3e is connected to each of the cylinder 3a and the end (cylinder end) of 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 part 3d provided at the end of the cylinder 3a and the cylinder 3b is exposed to the inside of the plunger cover 3e. In the present embodiment, a fifth pipe 65 of the exhaust gas supply unit 60, which will be described later, is connected to the plunger cover 3e. Exhaust gas X4 described later is supplied from the exhaust gas supply unit 60 to the inside of the plunger cover 3e.

  The cooling jacket 3 f is disposed at the end of the cylinder 3 a and the cylinder 3 b so as to cover the seal portion 3 d from the outer side in the radial direction. The cooling jacket 3 f is an annular pipe installed around the seal portion 3 d and is connected to a fifth pipe 65 described later of the exhaust gas supply unit 60. The cooling jacket 3 f cools the seal portion 3 d by the exhaust gas supply unit 60 supplying exhaust gas X 4 described later to the inside.

  The pump drive unit 32 includes a servomotor 32a, a drive gear 32b, a driven gear 32c, a screw shaft 32d, and a nut 32e. The servomotor 32a is connected to an external power supply 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 servomotor 32a, and is rotationally driven by the servomotor 32a. The driven gear 32c is in mesh with the drive gear 32b, and is driven to rotate as the drive gear 32b is rotationally driven. The screw shaft 32d is fixed to the driven gear 32c, and is rotated as the driven gear 32c is rotationally driven. The screw shaft 32d is disposed such that its axial center is parallel to the plunger 3c. The nut 32e is screwed with the screw shaft 32d, and is moved in the direction along the axial center of the screw shaft 32d by the rotation of the screw shaft 32d. The nut 32e is fixed to the plunger 3c. Therefore, the plunger 3c is moved in a direction along the axial center of the screw shaft 32d (that is, a direction along the axial center of the plunger 3c) by moving the nut 32e along the axial center of the screw shaft 32d.

  In such a pressure boosting unit 30, rotational power is generated by the servomotor 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.

  Further, the rotational direction of the servomotor 32a is changed by the controller 70 in a constant cycle. For this reason, the plunger 3c repeats reciprocating motion at a constant cycle. As a result, the liquefied gas for injection X2 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 p3. Further, the chiller 40 is connected to the preliminary pressure raising unit 20 via a pipe p5. The pipe p5 is a liquid feeding pipe for guiding the liquefied gas for cooling X3 from the preliminary pressure raising unit 20 to the chiller 40. The chiller 40 exchanges the injection liquefied gas X2 supplied from the pressure raising unit 30 through the pipe p3 with the cooling liquefied gas X3 supplied from the preliminary pressure raising unit 20 through the pipe p5, whereby the injection liquefied gas X2 is generated. Heat exchanger to adjust the temperature of the

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

  The exhaust gas supply unit 60 includes a first pipe 61 connected to the preliminary pressurizing heat exchanger 21, a second pipe 62 connected to the chiller 40, and a third pipe 63 (gas-feeding pipe exhaust pipe) surrounding the pipe p5. A fourth pipe 64 (exhaust pipe for injection 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 preliminary pressurizing heat exchanger 21 of the preliminary pressure raising 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 pressure-boosting heat exchanger 21 from the preliminary pressure-boosting section 20 to the third pipe 63. One end of the second pipe 62 is connected to the chiller 40, and the other end is 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 to the fourth pipe 64 from the chiller 40.

  The third pipe 63 is a pipe through which the pipe p5 is inserted, and is disposed between the preliminary pressure raising unit 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 pressure raising 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 p4 is inserted, and is disposed 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 booster 30, and the fifth pipe 65 is a plunger cover 3e for the exhaust X4 supplied from the third pipe 63 and the fourth pipe 64. 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 servomotor 32a, and controls the servomotor 32a while confirming the detection signal of the pressure gauge 71. The pressure gauge 71 is installed in a pipe p31 connected to the cylinder A and the cylinder C, a pipe p32 connected to the cylinder B and the cylinder D, and a pipe p3 which is a collective pipe of the pipe p31 and the pipe p32 There is.

  Here, as shown in FIG. 4, the controller 70 controls the servomotor 32a so that the pressure increase timings of the cylinders A to D are displaced for a predetermined period so that the pressure of the pipe p3 is always constant. Specifically, the controller 70 controls the pressure raising unit 30 such that the reciprocation cycle of the plunger 3 c of one plunger pump 31 and the reciprocation cycle of the plunger 3 c 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 pressurizing unit 20 as the liquefied gas for injection X2 is the same as the liquefied gas X3 for cooling. It is pre-boosted while being cooled by heat exchange. The pre-pressured injection liquefied gas X2 is further pressurized by the pressure raising unit 30, and temperature-adjusted by heat exchange with the cooling liquefied gas X3 by the chiller 40, and then injected from the injection unit 50.

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

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

  Further, in the liquefied gas injection device 1 of the present embodiment, the preliminary pressure increase heat exchanger 21 and the chiller 40 are provided as heat exchangers. Therefore, the exhaust X4 can be obtained from the preliminary pressure raising heat exchanger 21 and the chiller 40, and the exhaust X4 having a sufficient flow rate can be supplied to the pressure raising unit 30.

  Further, in the liquefied gas injection device 1 of the present embodiment, the exhaust gas supply unit 60 includes the third pipe 63 surrounding the pipe p5 and the fourth pipe 64 surrounding the pipe p4. For this reason, it is possible to suppress the heat absorption of the cooling liquefied gas X3 in the pipe p4 and the heat absorption of the injection 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 servomotor 32a as a power source. For this reason, compared with the case where a hydraulic mechanism is used, the amount of heat generated from the power source can be suppressed, and the temperature rise of the seal portion 3d can be suppressed. Further, since the calorific value of the motive power source is small, the servo motor 32a which is the motive 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 are considered.
(1) In the above embodiment, the pressure booster 30 has two plunger pumps 31. However, the present invention is not limited to this, and it is also possible to adopt a configuration in which the pressure raising unit 30 includes one plunger pump 31 or three or more plunger pumps 31.

(2) In the said embodiment, the cooling jacket 3f, the 3rd piping 63 which encloses the piping p5, and the 4th piping 64 which encloses the piping p4 were provided. However, it is also possible to adopt a configuration that omits any or all of these.

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

Reference Signs List 1 liquefied gas injection device 3a cylinder 3b cylinder 3c plunger 3c1 end 3c2 other end 3d seal portion 3e plunger cover 3f cooling jacket 10 liquefied gas supply portion 20 preliminary pressure raising portion 21 preliminary pressure raising heat exchanger 22 preliminary pressure raising pump 30 pressure portion 31 plunger Pump 32 Pump drive unit 32a Servomotor 32b Drive gear 32c Driven gear 32d Screw shaft 32e Nut 40 Chiller 50 Injection unit 60 Exhaust supply unit (exhaust supply means)
61 1st pipe 62 2nd pipe 63 3rd pipe (exhaust pipe for liquid feed pipe)
64 4th piping (exhaust pipe for injection pipe)
65 fifth piping 70 controller 71 pressure gauge A cylinder B cylinder C cylinder D cylinder p1 piping p2 piping p21 piping p22 piping p3 piping p31 piping p32 piping p4 piping (injection pipe)
p5 piping (liquid supply pipe)
X1 liquefied gas X2 liquefied gas for injection X3 liquefied gas for cooling X4 exhaust

Claims (6)

A heat exchanger for cooling the liquefied gas for injection, which is a liquefied gas whose temperature has been raised by pressure increase, by heat exchange with a liquefied gas for cooling, which is a liquefied gas used as a refrigerant;
A liquefied gas injection device comprising: a seal portion installed at a plunger inlet / outlet opening of a cylinder end and a plunger pump for pressurizing the liquefied gas for injection.
A plunger cover connected to the cylinder end and surrounding a portion of the plunger;
An exhaust gas supply means for supplying the exhaust gas from the heat exchanger containing the vaporized liquefied gas for cooling 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 supply means also supplies the exhaust to the cooling jacket.   As the heat exchanger, there is provided a preliminary pressure raising heat exchanger installed in a preliminary pressure-boosting section for preliminary pressure-raising the liquefied gas for injection before being supplied to the plunger pump, and the liquid for injection pressure boosted by the plunger pump The liquefied gas injection device according to claim 1 or 2, further comprising: a chiller for adjusting the temperature of the gas. A liquid feed pipe for guiding the liquefied gas for cooling to the chiller from the preliminary pressurizing section;
The liquefied gas injection device according to claim 3, wherein the exhaust gas supply means includes a liquid feed pipe exhaust pipe into which the liquid feed pipe is inserted and which guides the exhaust gas. And an injection pipe for guiding the liquefied gas for injection from the chiller to the injection unit,
The liquefied gas injection device according to claim 3 or 4, wherein the exhaust gas supply means includes an injection pipe exhaust pipe into which the injection pipe is inserted and which guides the exhaust gas. The liquefied gas injection device according to any one of claims 1 to 5, further comprising a servomotor for driving the plunger pump.

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