Protector for capillary probe

Abstract

A protector for a capillary probe (6). The protector comprises a needle (1), a filter screen (2), a first protective sleeve (4) sleeved on a casing (3), and a second protective sleeve (5) sleeved on the first protective sleeve (4), wherein the second protective sleeve (5) is provided with a through hole in which the filter screen (2) is accommodated, both ends of the second protective sleeve (5) and the first protective sleeve (4) are sealingly connected to the casing (3), and a chamber is formed between the first protective sleeve (4) and the casing (3); a capillary probe (6) is inserted into the chamber, with one end of the capillary probe (6) connected to a capillary tube (7) and the other end provided with the needle (1), the needle (1) facing the filter screen (2); and when the protector is lowered to a designated coal seam outside the filter screen (2), gas is injected into the capillary probe (6), pushing the needle (1) out to pierce through the first protective sleeve (4), allowing gas from the designated coal seam to flow into the chamber through the filter screen (2). The protector has a simple structure and is reliable, and can prevent the capillary probe (6) from colliding with a borehole wall when lowered in, protecting the capillary probe (6) against contamination by mud during well cementing.

Description

Protector for capillary probes

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202311620767.X filed on November 30, 2023, and cites the contents disclosed in the above patent application as part of this application. Technical Field

[0003] The present application relates to the technical field of test protection devices, and in particular to a protector for a capillary probe. Background Art

[0004] Underground coal gasification technology is a clean and efficient coal utilization technology that integrates the three major processes of well construction, coal mining, and gasification. It is one of the key research directions in the new energy and new business fields.

[0005] Coal seam pressure during underground coal gasification (UCG) production is a key parameter for maintaining normal UCG production and controlling syngas quality. Because UCG bottomhole temperatures range from 600 to 800°C, all electronic, quartz, and other pressure sensors and related testing equipment are unable to operate under these conditions. Capillary pressure sensors, lacking any electronic components underground, are a highly cost-effective tool for pressure testing in high-temperature underground environments.

[0006] To ensure the safe and normal operation of capillary pressure sensors, they must be lowered into the production casing and secured there. However, capillary probes are prone to damage from collisions with the wellbore wall during lowering, and are also susceptible to mud contamination during cementing.

[0007] Summary of the Invention

[0008] In response to at least one problem in the prior art, the present application proposes a protector for a capillary probe. The structure of the capillary probe protector is simple and reliable, which can prevent the capillary probe from being easily damaged by collision with the well wall during the lowering process, and prevent the capillary probe from being contaminated by mud during the cementing process, thereby improving the safety of the capillary probe.

[0009] In order to solve the above technical problems, this application provides the following technical solutions:

[0010] The present application provides a capillary probe protector, comprising:

[0011] A needle, a filter, a first protective cover sleeved on the cannula, and a second protective cover sleeved on the first protective cover;

[0012] The second protective cover is provided with a first through hole, the filter screen is accommodated in the first through hole, both ends of the second protective cover and the first protective cover are sealedly connected to the sleeve, and a chamber is formed between the first protective cover and the sleeve;

[0013] The capillary probe is extended into the chamber, one end of the capillary probe is connected to the capillary tube, the connection between the capillary tube and the chamber is sealed, and the other end of the capillary probe is provided with a needle, which faces the inner side of the filter screen;

[0014] When the protector is lowered to the designated coal seam outside the filter, gas is injected into the capillary probe through the capillary tube. The gas pushes the needle out and pierces the first protective cover, and the gas in the designated coal seam flows into the chamber through the filter.

[0015] In one embodiment, the first protective sleeve is a hollow rubber protective sleeve, and water is contained in the hollow rubber protective sleeve.

[0016] In one embodiment, the first protective cover is in close contact with the second protective cover.

[0017] In one embodiment, the needle is a hollow needle;

[0018] The hollow needle includes: a needle plug, a needle stem and a needle tip which are connected in sequence; a channel is provided in the needle plug, and the needle tip faces the inner side of the filter screen.

[0019] In one embodiment, the hollow needle further comprises: an aluminum metal film, the aluminum metal film completely blocking the channel;

[0020] When the protector is lowered to the designated coal seam outside the filter, the capillary tube injects gas into the capillary probe, and the gas pushes the needle out, pierces the first protective cover and breaks through the aluminum metal film.

[0021] In one embodiment, the capillary probe is L-shaped, and the bend is arc-shaped.

[0022] In one embodiment, a second through hole is opened at one end of the second protective cover, and a third through hole is opened at one end of the first protective cover. The capillary probe extends into the chamber through the second through hole and the third through hole in sequence, and the capillary is sealed and connected to the second through hole and the third through hole via a one-way valve joint.

[0023] In one embodiment, one end of the second protective sleeve and the first protective sleeve are sealed and connected to the sleeve through a first sealing plug, and the other end of the second protective sleeve and the first protective sleeve are sealed and connected to the sleeve through a second sealing plug.

[0024] In one embodiment, the side wall of the needle barrel is provided with a plurality of fourth through holes.

[0025] In one embodiment, the second protective sleeve is a metal protective sleeve.

[0026] It can be seen from the above technical solution that the present application provides a protector for a capillary probe. The protector includes: a needle, a filter, a first protective sleeve mounted on the sleeve, and a second protective sleeve mounted on the first protective sleeve; the second protective sleeve is provided with a first through hole, the filter is accommodated in the first through hole, both ends of the second protective sleeve and the first protective sleeve are sealed with the sleeve, and a chamber is formed between the first protective sleeve and the sleeve; the capillary probe extends into the chamber, one end of the capillary probe is connected to the capillary tube, the connection between the capillary tube and the chamber is sealed, and the other end of the capillary probe is provided with a needle, the needle facing the inside of the filter; when the protector is lowered to the designated coal seam outside the filter, gas is injected into the capillary probe through the capillary tube, the gas pushes the needle out and pierces the first protective sleeve, and the gas in the designated coal seam flows into the chamber through the filter. The structure of the protector of the capillary probe is simple and reliable, which can prevent the capillary probe from colliding with the well wall during the lowering process and causing damage, and at the same time prevent the capillary probe from being damaged. The capillary probe is protected from mud contamination during the cementing process, thereby improving the safety of the capillary probe; the second protective cover protects the capillary probe from colliding with the well wall during the lowering process; the first protective cover can play a further buffering role; the needle pierces the first protective cover, the first protective cover ruptures, and the gas enters the capillary probe from the filter, which can prevent the capillary probe from being contaminated by mud during the cementing process; specifically, the protector of the capillary probe can protect the capillary probe from being safely lowered during the drilling and completion process; prevent the capillary probe from being blocked by mud and other debris during the lowering process; and prevent the capillary probe from colliding with the well wall and causing damage during the lowering process; when the capillary probe is lowered into place, after the hollow needle pierces the first protective cover under pressure, the capillary probe can form a larger pressure-conducting space to ensure rapid pressure transmission. In other words, the hollow structure of the capillary needle can ensure that gas is quickly transferred from the coal seam to the capillary. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] FIG1 is a first structural schematic diagram of a protector for a capillary probe in an embodiment of the present application;

[0029] FIG2 is a schematic diagram of the relationship between the needle, the capillary probe, the first protective cover, and the filter screen before the needle is pressed out in an embodiment of the present application;

[0030] FIG3 is a schematic diagram of the relationship between the needle, the capillary probe, the first protective cover, and the filter screen after the needle is pressed out in an embodiment of the present application;

[0031] FIG4 is a cross-sectional schematic diagram of a hollow needle in an embodiment of the present application;

[0032] FIG5 is a side view of a hollow needle in an embodiment of the present application;

[0033] FIG6 is a second structural schematic diagram of the protector of the capillary probe in the embodiment of the present application.

[0034] Explanation of symbols: 1. Needle; 01. Needle plug; 02. Needle stem; 03. Needle tip; 04. Channel; 05. Fourth through hole; 06. Aluminum metal membrane; 2. Filter; 3. Casing; 4. First protective cover; 5. Second protective cover; 6. Capillary probe; 7. Capillary; 8. One-way valve connector; 9. First sealing plug; 10. Second sealing plug; 11. Wellbore. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] To improve gasification operation stability, resource conversion rate, and gasification efficiency, the control process for underground coal gasification (UCG) requires prior research on control methods and the development of a gasification operating system. The bottomhole pressure of the production well at the end of the gasification chamber in the coal seam is a key operating parameter. For specific coal seam conditions, obtaining the bottomhole pressure of the UCG production well is an important basis for determining the production well operating system. Therefore, during the implementation of the on-site process plan, real-time bottomhole pressure data must be obtained to determine the production status under the target coal seam and the corresponding operating conditions. This serves as a key basis for adjusting the plan during the pilot demonstration and commercial development phases. Because the ambient temperature at the bottom of a CBM production well is relatively high, typically 600-800°C, conventional pressure gauges cannot be used in this environment due to the temperature limit of their electronic components within 200°C. Therefore, capillary pressure sensors are currently a highly cost-effective tool for measuring pressure in high-temperature underground environments.

[0037] This embodiment of the application proposes a method for pushing a hollow needle through a capsule. It also proposes a pressure-balancing method using a first protective cover to ensure close contact between the first and second protective covers, preventing mud contamination and probe clogging. The second protective cover is fixed to the casing to prevent damage to the probe from colliding with the wellbore wall during lowering. The second protective cover also provides a connection between the capillary probe and the coal seam. The main technical specifications of the capillary probe protector provided in this embodiment of the application include an applicable pressure range of 0 to 50 MPa, a temperature range of 0 to 1000°C, and a depth range of 0 to 4000 m.

[0038] The capillary probe protector provided in this application can effectively protect the capillary probe from being contaminated or blocked by debris such as mud during the lowering process, can effectively prevent the capillary probe from colliding with the well wall during the lowering process and causing mechanical damage, can form an effective space to keep the capillary probe in good communication with the coal seam outside the casing, and provide certain protection during the capillary pressure sensor entering the well. Furthermore, it can be used to adjust the bottom hole pressure data of the coal underground gasification production well during the production process, provide data for gasification operation parameters (gasification agent ratio, injection rate), and is suitable for basic research on the gasification process of shallow, medium and deep coal underground gasification, as well as research on gasification operation control methods and process technologies. It can effectively support normal coal seam pressure testing of underground coal gasification, provide more reliable pressure conditions at the bottom of the synthesis gas production well for underground coal gasification, and provide technical support for controlling the quality and output of underground coal gasification synthesizers. It is of great significance to improve the level of basic research on underground coal gasification, improve the experimental capabilities of underground coal gasification, and promote the development of underground coal gasification technology and business.

[0039] The details are described in the following embodiments.

[0040] To prevent the capillary probe from being damaged by collision with the well wall during the lowering process, and to prevent the capillary probe from being contaminated by mud during the cementing process, thereby improving the safety of the capillary probe, the present application provides an embodiment of a protector for a capillary probe, as shown in FIG1 . In this embodiment, the protector specifically includes the following contents:

[0041] The device comprises a needle 1, a filter 2, a first protective sleeve 4 overlying a sleeve 3, and a second protective sleeve 5 overlying the first protective sleeve 4. The second protective sleeve 5 defines a first through-hole, into which the filter 2 is received. Both ends of the second protective sleeve 5 and the first protective sleeve 4 are sealed to the sleeve 3, forming a chamber between the first protective sleeve 4 and the sleeve 3. A capillary probe 6 extends into the chamber, one end of which is connected to a capillary tube 7, the connection between the capillary tube and the chamber being sealed. The other end of the capillary probe 6 is provided with a needle 1, which faces the inside of the filter 2. When the protector is lowered until the outside of the filter 2 is within a designated coal seam, gas is injected into the capillary probe 6 through the capillary tube. This gas pushes the needle 1 out and pierces the first protective sleeve 4, allowing gas in the designated coal seam to flow into the chamber through the filter 2. The second protective sleeve can be made of a rigid material, such as steel. The first protective sleeve can be made of an elastic material, such as rubber.

[0042] Specifically, the filter can be fixedly connected to the first through-hole and completely obstruct the first through-hole. Before the gas pushes the needle 1 out and pierces the first protective sleeve, the chamber formed between the first protective sleeve and the sleeve is a sealed chamber. After the protector is mounted and fixed to the capillary probe and sleeve, the protector and capillary probe can be lowered into the wellbore 11 along with the sleeve until the designated coal seam is located outside the filter. The designated coal seam can be specified based on actual needs and is not limited in this application. Gas can be injected into the capillary probe 6 from the surface via the capillary tube. The injected gas can be nitrogen. After the first protective sleeve 4 ruptures, the capillary tube can be stopped from injecting gas into the capillary probe 6. The gas in the designated coal seam can represent air in the designated coal seam. The gas in the designated coal seam flows into the chamber through the filter 2, transmitting the coal seam pressure to the capillary probe 6, which is then transmitted to the surface pressure measuring device via the capillary tube. The well casing can be an underground coal gasification production well casing or a vertical well casing. In order to improve the efficiency of pushing the needle, the capillary probe can be L-shaped, and the bend is arc-shaped. As shown in Figure 2, the needle is inside the capillary probe before being pushed out, and as shown in Figure 3, the needle pierces the first protective cover after being pushed out.

[0043] To further enhance the cushioning effect of the first protective cover when the second protective cover collides with the well wall, the first protective cover is preferably a hollow rubber protective cover filled with water. The first and second protective covers can be in close contact. When the needle pierces the hollow rubber protective cover, rupturing it, the water within the hollow rubber protective cover flows out.

[0044] To ensure rapid gas transfer from the coal seam to the chamber, as shown in Figures 4 and 5, needle 1 is preferably a hollow needle. The hollow needle comprises a pintle 01, a stem 02, and a tip 03, which are connected in sequence. Pintle 01 is provided with a channel 04, with the tip facing the inside of the filter. Channel 04 in the pintle, similar to the channel in an infusion needle, is primarily used to rapidly exchange air inside and outside the protector after puncturing the rubber sleeve, establishing a stable pressure-transferring space.

[0045] Specifically, the needle plug is slightly smaller than the diameter of the capillary and is placed in the capillary probe. When the pressure is large enough, the pressure on the side of the needle plug is greater than the friction force, and it will be pushed forward by the air pressure, and the needle does not need to be retracted. When the protector is lowered to the designated coal seam outside the filter 2, gas is injected into the capillary probe 6 from the ground through the capillary, and the gas pushes the hollow needle out and pierces the first protective sleeve 4. The gas in the coal seam can enter the chamber through the rupture of the first protective sleeve 4, or enter the capillary probe 6 through the needle tip 03, the needle stem 02 and the needle plug 01. The capillary is pressurized and inflated from the top of the ground capillary. The gas passes through the one-way valve and pushes the hollow needle in the curved part inside the capillary, piercing the wall of the first protective sleeve 4, so that the capillary is connected to the annular space protected therein, and can be connected to the external coal seam through the filter 2, that is, the pressure in the coal seam outside the casing can be measured. It can effectively prevent external mud and the like from entering the capillary protector, and at the same time protect the capillary protector from colliding with the well wall and causing mechanical damage during the lowering process; the gas is transmitted to the capillary probe through the hollow structure inside the hollow needle, which can further improve the timeliness and efficiency of the gas transmission from the coal seam to the capillary probe.

[0046] To improve the efficiency of pushing the needle, the hollow needle preferably also includes an aluminum metal film 06 that completely blocks the channel 04. When the protector is lowered to the designated coal seam outside the filter 2, the capillary tube injects gas into the capillary probe 6. This gas pushes the needle 1 out, piercing the first protective cover 4 and breaking through the aluminum metal film 06. When the first protective cover 4 breaks through the aluminum metal film, the capillary probe 6, channel 04, needle stem 02, and needle tip 03 can be connected in sequence.

[0047] To further create a larger pressure-conducting space within the capillary probe and ensure rapid pressure transmission, a plurality of fourth through holes 05 are preferably provided on the sidewall of the needle stem 02. When the hollow needle pierces the first protective sheath 4, at least a portion of the plurality of fourth through holes 05 remain within the chamber, thereby accelerating the transmission of gas from the coal seam into the chamber via the through holes.

[0048] To prevent water from flowing back through the capillary tube, a second through-hole is preferably defined at one end of the second protective sleeve 5, and a third through-hole is defined at one end of the first protective sleeve 4. The capillary probe 6 extends into the chamber through the second and third through-holes, respectively. The capillary tube is sealed to the second and third through-holes via a one-way valve connector 8. When the needle penetrates the rubber protective sleeve, the one-way guide valve opens, connecting the capillary tube to the space in the second protective sleeve. This increases the pressure transmission space and facilitates pressure transmission to the capillary tube.

[0049] To further improve the stability of the connection between the protector and the sleeve 3, preferably, one end of the second protective sleeve 5 and the first protective sleeve 4 are sealed to the sleeve 3 via a first sealing plug 9, and the other end of the second protective sleeve 5 and the first protective sleeve 4 are sealed to the sleeve 3 via a second sealing plug 10. Both the first sealing plug 9 and the second sealing plug 10 can be metal threaded sealing plugs.

[0050] To further illustrate the present solution, the present application provides an application example of a protector for a capillary probe. In this application example, the protector includes: a pressure measuring capillary; a one-way valve; a metal protective sleeve; a metal threaded sealing plug; a filter; a rubber protective sleeve; and a hollow needle.

[0051] A metal protective sleeve is placed on the outside of the vertical well casing and sealed with a metal threaded sealing plug. A filter structure is installed at the bottom of the metal protective sleeve, connecting the metal protective sleeve to the outside air while preventing large mud particles and other debris from entering the metal protective sleeve. A rubber protective sleeve is placed inside the metal protective sleeve and filled with water to support the rubber protective sleeve. The rubber protective sleeve is tightly connected to the metal protective sleeve, occupying the space inside the metal protective sleeve and preventing external mud and other debris from entering the metal protective sleeve. A one-way valve connector passes through the metal protective sleeve and the rubber protective sleeve to connect and place a pressure measuring capillary tube to prevent water backflow in the pressure measuring capillary tube. The pressure measuring capillary tube passes through the one-way valve, the metal protective sleeve, and the space inside the rubber protective sleeve. The bottom of the pressure measuring capillary tube is bent horizontally, and a hollow needle is placed inside the horizontal section. The end of the pressure measuring capillary tube should be placed on the same level as the filter screen, facing the filter screen. Applying sufficient pressure to the capillary pressure gauge pushes out the hollow needle, puncturing the rubber sheath. Once the rubber sheath is punctured, the water inside flows out, allowing air to enter the protector and into the capillary pressure gauge, transmitting the pressure to the surface pressure measuring device. The lower end of the capillary pressure gauge passes through a one-way valve and into both the metal and rubber sheaths. Once the rubber sheath is filled with water, it firmly connects to the metal sheath. The lower end of the capillary pressure gauge is placed level with the filter screen, ensuring easy puncture. The outlet faces one side of the rubber sheath and houses a hollow needle. Pressure is applied to the rubber sheath, puncturing the rubber sheath. Water inside the rubber sheath flows out of the protector and then through the filter screen to the outside world. The tight connection between the rubber and metal sheaths effectively prevents the ingress of mud and other debris. The capillary tube, protected by both the metal and rubber sheaths, remains safe and contaminant-free.

[0052] To prevent the capillary probe from being damaged by collision with the well wall during the lowering process, and to prevent the capillary probe from being contaminated by mud during the cementing process, thereby improving the safety of the capillary probe, as shown in FIG6 , the present application provides another embodiment of a protector for a capillary probe. In this embodiment, the protector specifically includes the following contents:

[0053] A first protective cover 4 is sleeved on the sleeve 3, and a second protective cover 5 is sleeved on the first protective cover; the second protective cover is provided with a first through hole, the filter screen 2 is accommodated in the first through hole, both ends of the second protective cover and the first protective cover are sealed with the sleeve, and a chamber is formed between the first protective cover and the second protective cover; a capillary probe 6 extends into the chamber, one end of the capillary probe is connected to the capillary tube 7, and the connection between the capillary tube and the chamber is sealed; the gas in the coal seam outside the filter screen flows into the chamber through the filter screen.

[0054] Preferably, one end of the second protective sleeve and the first protective sleeve is sealed to the sleeve via a first sealing plug 9, and the other end of the second protective sleeve and the first protective sleeve is sealed to the sleeve via a second sealing plug 10. Both the first sealing plug and the second sealing plug can be metal threaded sealing plugs.

[0055] Preferably, the first protective cover is a hollow rubber protective cover, and the hollow rubber protective cover body is filled with water.

[0056] Preferably, a second through hole is opened at one end of the second protective sleeve, and the capillary probe extends into the chamber through the second through hole. One end of the capillary probe is connected to the capillary, and the capillary is sealed and connected to the through hole via a one-way valve joint 8.

[0057] Specifically, the second protective sheath can be a metal sheath. The pressure-measuring capillary probe is inserted into the metal sheath through a one-way valve and placed outside the rubber sheath. The rubber sheath is filled with water and tightly connected to the metal sheath. There are no specific requirements for the placement of the capillary probe. The capillary probe outlet faces one side of the rubber sheath and is connected to the outside world through a filter. With the capillary tube inside the metal sheath and outside the rubber sheath, the placement of the capillary tube end is less critical, resulting in higher efficiency.

[0058] Specific embodiments are used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A protector for a capillary probe, characterized in that, it includes: a needle, a filter screen, a first protective sleeve sleeved on a sleeve, and a second protective sleeve sleeved on the first protective sleeve; the second protective sleeve is provided with a first through hole, the filter screen is accommodated in the first through hole, both ends of the second protective sleeve and the first protective sleeve are hermetically connected to the sleeve, and a chamber is formed between the first protective sleeve and the sleeve; the capillary probe extends into the chamber, one end of the capillary probe is connected to a capillary, the connection between the capillary and the chamber is hermetically connected, the other end of the capillary probe is provided with the needle, and the needle faces the inside of the filter screen; when the protector is lowered to a specified coal seam outside the filter screen, gas is injected into the capillary probe through the capillary, and the gas pushes the needle out and pierces the first protective sleeve, and the gas in the specified coal seam flows into the chamber through the filter screen.

2. The protector for a capillary probe according to claim 1, characterized in that, the first protective sleeve is a hollow rubber protective sleeve, and water is contained in the body of the hollow rubber protective sleeve.

3. The protector for a capillary probe according to claim 1, characterized in that, the first protective sleeve and the second protective sleeve are in close contact with each other.

4. The protector for a capillary probe according to claim 1, characterized in that, the needle is a hollow needle; the hollow needle includes: a needle hub, a needle shaft and a needle tip connected in sequence; the needle hub is provided with a channel, and the needle tip faces the inside of the filter screen.

5. The protector for a capillary probe according to claim 4, characterized in that, the hollow needle further includes: an aluminum metal film, and the aluminum metal film completely blocks the channel; when the protector is lowered to a specified coal seam outside the filter screen, gas is injected into the capillary probe through the capillary, and the gas pushes the needle out, pierces the first protective sleeve and breaks through the aluminum metal film.

6. The protector for a capillary probe according to claim 1, characterized in that, the capillary probe is L-shaped, and the turning point is arc-shaped.

7. The protector for a capillary probe according to claim 2, characterized in that, one end of the second protective sleeve is provided with a second through hole, one end of the first protective sleeve is provided with a third through hole, the capillary probe extends into the chamber through the second through hole and the third through hole in sequence, and the capillary is hermetically connected to the second through hole and the third through hole through a one-way valve joint.

8. The protector for a capillary probe according to claim 1, characterized in that, one end of the second protective sleeve and the first protective sleeve is hermetically connected to the sleeve through a first sealing plug, and the other end of the second protective sleeve and the first protective sleeve is hermetically connected to the sleeve through a second sealing plug.

9. The protector for a capillary probe according to claim 4, characterized in that, the side wall of the needle shaft is provided with a plurality of fourth through holes.

10. The protector for a capillary probe according to claim 1, characterized in that, the second protective sleeve is a metal protective sleeve.

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