A concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device

Abstract

The utility model discloses a concentric coiled tubing reverse circulation jet pump negative pressure sand washing device, including well shaft, concentric double -tube coiled tubing, reverse cycle jet pump and sand washing device, and concentric double -tube coiled tubing includes the outer tube and inner tube of coaxial setting, the bottom of inner tube is connected with reverse cycle jet pump, and reverse cycle jet pump includes spacing connecting sleeve, X type cross joint and sand washing nozzle, the bottom of outer tube is connected with sand washing device, and sand washing device includes suction cover, diffusion pipe and nozzle, and reverse cycle jet pump and sand washing device liquid path are parallelly connected, the utility model discloses a inner tube, X type cross joint, suction cover, diffusion pipe and nozzle are set up, and through power liquid, the flow of diffusion pipe and nozzle is carried out in two ways, can be driven mixed liquid and is discharged through power liquid, need not set up annular space packoff unit in negative pressure sand washing work, avoid the problem that positive circulation jet pump annular back row mixed sand liquid is easy to block, and simultaneously can continuously carry out negative pressure sand washing work, reduce construction risk.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas extraction technology, specifically to a concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device. Background Technology

[0002] Compared to vertical, directional, and cluster wells, sand flushing in horizontal wells is more complex and unique. Conventional hydraulic sand flushing technology faces challenges such as obstruction during the lowering and raising of the flushing tubing string, and load changes make it difficult to assess downhole conditions. Furthermore, during the return of formation sand, sand can easily accumulate again at inclined sections, causing sand blockage. The lower sand bed is difficult to clean, and the flushing fluid can easily carry sand into the formation, leading to reservoir damage. Currently, the coiled tubing truck used for sand flushing in domestic oil well workover uses a single tubing string.

[0003] For example, utility model patent application number CN201721131884.X discloses a process string for achieving negative pressure sand flushing using coiled tubing, comprising: coiled tubing, spaced apart and sleeved within a production string; a negative pressure sand flushing device located within the production string and connected to the lower end of the coiled tubing; wherein the negative pressure sand flushing device includes: a main sand flushing pipe connected to the lower end of the coiled tubing; a bridge-type sleeve sleeved within the main sand flushing pipe; and an annular sealing unit, circumferentially sealingly clamped between the production string and the main sand flushing pipe; a filter screen is circumferentially formed at the end of the main sand flushing pipe away from the coiled tubing. By adopting the above structure, this process string for achieving negative pressure sand flushing using coiled tubing combines the technical advantages of continuous pressurization and negative pressure sand flushing using coiled tubing, solving the problems of high cost, large pressure loss along the well in deep wells, and the inability to continuously pressurize sand flushing operations using concentric coiled tubing negative pressure sand flushing technology.

[0004] Although this process string using coiled tubing to achieve negative pressure sand flushing solves the problems of high cost, large pressure loss along the well in deep wells, and the inability to continuously perform pressurized sand flushing operations in concentric coiled tubing negative pressure sand flushing technology, its circumferential seal is sandwiched between the production tubing and the main sand flushing pipeline. This requires the installation of an annular sealing unit between the casing and tubing during negative pressure sand flushing operations. During sand flushing, the components of the annular sealing unit are easily jammed by sand, resulting in a high construction risk; further improvements are needed. Utility Model Content

[0005] The purpose of this utility model is to provide a concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device, which aims to improve the problem that an annular sealing unit needs to be set between the oil casing and tubing in negative pressure sand flushing, and the components of the annular sealing unit are easily stuck by sand during sand flushing construction, resulting in high construction risk.

[0006] This utility model is implemented as follows: A concentric coiled tubing reverse circulation jet pump negative pressure sand flushing device includes a wellbore, a concentric double-tube coiled tubing, a reverse circulation jet pump, and a sand flushing device. The concentric double-tube coiled tubing includes an outer tube and an inner tube arranged coaxially. The bottom of the inner tube is connected to the reverse circulation jet pump, which includes a limiting connecting sleeve, an X-type cross joint, and a sand flushing nozzle. The bottom of the outer tube is connected to the sand flushing device, which includes a suction sleeve, a diffuser tube, and a nozzle. The reverse circulation jet pump and the sand flushing device are connected in parallel in terms of fluid circuits.

[0007] Preferably, one end of the inner tube is fitted with a diffuser tube, and the end of the outer tube near the diffuser tube is abutted against the outer wall of the diffuser tube by a limiting connecting sleeve; from the inside to the outside of the diffuser tube, a suction sleeve and an X-type cross connector are sequentially fitted, and the same end of the suction sleeve and the X-type cross connector abuts against the limiting connecting sleeve and forms a second cavity; the other end is provided with a nozzle installed on the suction sleeve and a sand flushing nozzle installed on the X-type cross connector; a first cavity is provided between the suction sleeve and the X-type cross connector; a power fluid outlet hole communicating with the second cavity is provided on the limiting connecting sleeve; a mixed liquid outlet hole or a mixed liquid suction hole communicating with the first cavity is sequentially provided on the X-type cross connector and the suction sleeve; and a power fluid flow hole communicating with the second cavity is provided on the X-type cross connector.

[0008] Preferably, the outer wall of the outer tube is provided with a positioning ring, which is embedded in the wall of the outer tube and extends to the outside. The limiting connecting sleeve is fitted on the outer tube and abuts against the positioning ring. A locking sleeve is also fitted at the connection between the outer tube and the limiting connecting sleeve.

[0009] Preferably, the second cavity is connected to the area between the outer tube and the inner tube through the power fluid outlet hole, and to the area between the nozzle and the sand flushing nozzle through the power fluid flow hole.

[0010] Preferably, the first cavity is connected to the inside of the wellbore through a mixture outlet hole and to the area between the diffuser and the nozzle through a mixture intake hole.

[0011] Preferably, the diffuser tube includes a wide-mouth end and a narrow-mouth end, the wide-mouth end being fitted inside the inner tube, and the narrow-mouth end being disposed in the inhalation sleeve.

[0012] Preferably, the nozzle includes a nozzle inlet and a nozzle diffuser. The nozzle is disposed at one end of the suction sleeve near the sand flushing nozzle. The nozzle has a nozzle inlet at one end facing the suction sleeve and a nozzle diffuser at the other end.

[0013] Preferably, the sand flushing nozzle includes a sand flushing inlet and a sand flushing nozzle. The sand flushing nozzle is located at the end of the X-shaped cross joint away from the outer tube and is not in contact with the suction sleeve. The sand flushing nozzle has a sand flushing inlet at one end near the nozzle and a sand flushing nozzle at the other end.

[0014] Preferably, it also includes a sealing ring and a sand-flushing blind nozzle; the outer tube, locking sleeve, limiting connecting sleeve, X-type cross joint, suction sleeve, nozzle and sand-flushing nozzle are all provided with sealing rings at the parts where they abut against each other; the sand-flushing blind nozzle is a sealing structure and can be installed in place of the sand-flushing nozzle.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model, by setting an inner pipe, an X-type cross joint, a suction sleeve, a diffuser pipe and a nozzle, allows the power fluid to flow in two separate paths through the diffuser pipe and the nozzle. The power fluid can drive the mixed liquid to be discharged, eliminating the need for annular sealing units during negative pressure sand flushing. This avoids the problem of easy blockage of mixed sand liquid during annular backflow of positive circulation jet pumps, and allows for continuous negative pressure sand flushing, reducing construction risks.

[0017] 2. This utility model, by setting a sand-flushing blind nozzle, can perform a suction function through the sand-flushing blind nozzle for oil and gas testing, thereby improving well completion efficiency. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0019] Figure 2 This is a schematic diagram of the assembly structure of the inner tube and the outer tube of this utility model;

[0020] Figure 3 This is a radial cross-sectional view of the X-type cross interface of this utility model;

[0021] Figure 4 This is a schematic diagram of the assembly structure of the diffuser tube and nozzle of this utility model;

[0022] Figure 5 This is a schematic diagram of the structure of the sand-rinsing nozzle of this utility model;

[0023] Figure 6 This is a schematic diagram of the structure of the sand-flushing blind nozzle of this utility model.

[0024] In the diagram: 1. Wellbore; 2. Outer tube; 3. Inner tube; 4. Locking sleeve; 5. Limiting connection sleeve; 501. Power fluid outlet hole; 6. X-type cross joint; 601. Mixed fluid outlet hole; 602. Power fluid flow hole; 7. Suction sleeve; 701. Mixed fluid suction hole; 702. First cavity; 8. Diffuser; 801. Wide mouth end; 802. Narrow mouth end; 9. Nozzle; 901. Nozzle inlet; 902. Nozzle diffuser; 10. Sand flushing nozzle; 1001. Sand flushing inlet; 1002. Sand flushing nozzle; 11. Positioning ring; 12. Sealing ring; 13. Second cavity; 14. Sand flushing blind nozzle. Detailed implementation method:

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:

[0027] Example 1

[0028] like Figure 1 As shown, a concentric coiled tubing reverse circulation jet pump negative pressure sand flushing device includes a wellbore 1, concentric double-tube coiled tubing, a reverse circulation jet pump, and a sand flushing device. The concentric double-tube coiled tubing includes an outer tube 2 and an inner tube 3 arranged coaxially. The bottom of the inner tube 3 is connected to the reverse circulation jet pump, which includes a limiting connecting sleeve 5, an X-type cross joint 6, and a sand flushing nozzle 10. The bottom of the outer tube 2 is connected to the sand flushing device, which includes a suction sleeve 7, a diffuser 8, and a nozzle 9. The reverse circulation jet pump and the sand flushing device are connected in parallel in terms of fluid circuits. The inner tube 3 is coaxially arranged in the outer tube 2, and the diameter of the inner tube 3 is smaller than the diameter of the outer tube 2. An annular space is provided between the inner tube 3 and the outer tube 2. One end of the inner tube 3 is fitted with a diffuser tube 8. The end of the outer tube 2 near the diffuser tube 8 is abutted against the outer wall of the diffuser tube 8 by a limiting connecting sleeve 5. The outer wall of the diffuser tube 8 is provided with an annular abutment surface. One end of the limiting connecting sleeve 5 is fitted onto the outer tube 2, and the other end abuts against the abutment surface of the diffuser tube 8. The outer wall of the outer tube 2 is provided with a positioning ring 11, which is embedded in the wall of the outer tube 2 and extends to the outside. The limiting connecting sleeve 5 is fitted onto the outer tube 2 and abuts against the positioning ring 11 for limiting the fitting. A locking sleeve 4 is also fitted at the connection between the outer tube 2 and the limiting connecting sleeve 5. The locking sleeve 4 can prevent the connection between the outer tube 2 and the limiting connecting sleeve 5 from falling off.

[0029] like Figure 1 , Figure 2 and Figure 4As shown, from the inside to the outside, the diffuser 8 is fitted with a suction sleeve 7 and an X-type cross connector 6. Both the suction sleeve 7 and the X-type cross connector 6 abut against the limiting connecting sleeve 5 at the same end, forming a second cavity 13. The other ends are respectively fitted with a nozzle 9 and a sand-flushing nozzle 10, which are coaxially aligned. A first cavity 702 is provided between the suction sleeve 7 and the X-type cross connector 6. The first cavity 702 connects to the inside of the wellbore 1 through a mixed liquid outlet hole 601 and connects to the area between the diffuser 8 and the nozzle 9 through the mixed liquid suction hole 701, allowing the mixed liquid in the wellbore 1 to enter the first cavity 702 through the mixed liquid outlet hole 601. 02, and then enter the diffuser tube 8 through the mixed liquid suction hole 701 and exit from the inner tube 3; the limiting connecting sleeve 5 is provided with a through power fluid outlet hole 501 on the wall corresponding to the second cavity 13; the X-type cross joint 6 and the suction sleeve 7 are respectively radially provided with two sets of mixed liquid outlet holes 601 and two mixed liquid suction holes 701 at the positions corresponding to the first cavity 702; the diffuser tube 8 includes a wide end 801 and a narrow end 802, the wide end 801 is fitted in the inner tube 3, and the narrow end 802 is set in the suction sleeve 7; the wall of the X-type cross joint 6 is axially provided with a through power fluid flow hole 602 at the position corresponding to the second cavity 13.

[0030] like Figure 1 and Figures 4-6 As shown, nozzle 9 includes nozzle inlet 901 and nozzle diffuser 902. Nozzle 9 is located at the end of suction sleeve 7 near sand flushing nozzle 10. Nozzle 9 has nozzle inlet 901 at one end facing suction sleeve 7 and nozzle diffuser 902 at the other end. Sand flushing nozzle 10 includes sand flushing inlet 1001 and sand flushing nozzle 1002. Sand flushing nozzle 10 is located at the end of X-type cross joint 6 away from outer tube 2 and is not in contact with suction sleeve 7. Sand flushing nozzle 10 has sand flushing inlet 1001 at one end near nozzle 9 and sand flushing nozzle 1002 at the other end. It also includes sealing ring 12 and sand flushing blind nozzle 14. Sealing ring 12 is provided at the parts where outer tube 2, locking sleeve 4, limiting connecting sleeve 5, X-type cross joint 6, suction sleeve 7, nozzle 9 and sand flushing nozzle 10 abut against each other. Sand flushing blind nozzle 14 is a sealing structure and can replace sand flushing nozzle 10 for installation.

[0031] Example 2

[0032] like Figure 1As shown, a concentric coiled tubing reverse circulation jet pump negative pressure sand flushing device includes a wellbore 1, concentric double-tube coiled tubing, a reverse circulation jet pump, and a sand flushing device. The concentric double-tube coiled tubing includes an outer tube 2 and an inner tube 3 arranged coaxially. The bottom of the inner tube 3 is connected to the reverse circulation jet pump, which includes a limiting connecting sleeve 5, an X-type cross joint 6, and a sand flushing nozzle 10. The bottom of the outer tube 2 is connected to the sand flushing device, which includes a suction sleeve 7, a diffuser 8, and a nozzle 9. The reverse circulation jet pump... It is connected in parallel with the hydraulic circuit of the sand flushing device; the inner tube 3 is coaxially arranged in the outer tube 2, and a diffuser tube 8 is fitted at one end of the inner tube 3. The end of the outer tube 2 near the diffuser tube 8 is abutted against the outer wall of the diffuser tube 8 through a limiting connecting sleeve 5. A positioning ring 11 is provided on the outer wall of the outer tube 2. The positioning ring 11 is embedded in the wall of the outer tube 2 and extends to the outside. The limiting connecting sleeve 5 is fitted on the outer tube 2 and abuts against the positioning ring 11. A locking sleeve 4 is also fitted at the connection between the outer tube 2 and the limiting connecting sleeve 5.

[0033] like Figure 1 , Figure 2 and Figure 4 As shown, from the inside to the outside, the diffuser 8 is fitted with a suction sleeve 7 and an X-type cross connector 6. Both the suction sleeve 7 and the X-type cross connector 6 abut against the limiting connecting sleeve 5 at the same end, forming a second cavity 13. The other ends are respectively fitted with a nozzle 9 and a sand flushing nozzle 10. A first cavity 702 is provided between the suction sleeve 7 and the X-type cross connector 6. The first cavity 702 connects to the inside of the wellbore 1 through a mixed liquid outlet hole 601 and connects to the area between the diffuser 8 and the nozzle 9 through a mixed liquid suction hole 701. The limiting connecting sleeve... A through-hole 501 of kinetic fluid is provided on the wall of the second cavity 13. The X-type cross joint 6 and the suction sleeve 7 are respectively radially provided with multiple mixed liquid outflow holes 601 and mixed liquid suction holes 701 at the positions corresponding to the first cavity 702. The diffuser tube 8 includes a wide-mouth end 801 and a narrow-mouth end 802. The wide-mouth end 801 is fitted in the inner tube 3, and the narrow-mouth end 802 is set in the suction sleeve 7. A through-hole 602 of kinetic fluid is provided axially on the wall of the X-type cross joint 6 at the position corresponding to the second cavity 13.

[0034] like Figure 1 and Figures 4-6As shown, nozzle 9 includes nozzle inlet 901 and nozzle diffuser 902. Nozzle 9 is located at the end of suction sleeve 7 near sand flushing nozzle 10. Nozzle 9 has nozzle inlet 901 at one end facing suction sleeve 7 and nozzle diffuser 902 at the other end. Sand flushing nozzle 10 includes sand flushing inlet 1001 and sand flushing nozzle 1002. Sand flushing nozzle 10 is located at the end of X-type cross joint 6 away from outer tube 2 and is not in contact with suction sleeve 7. Sand flushing nozzle 10 has sand flushing inlet 1001 at one end near nozzle 9 and sand flushing nozzle 1002 at the other end. It also includes sealing ring 12 and sand flushing blind nozzle 14. Sealing ring 12 is provided at the parts where outer tube 2, locking sleeve 4, limiting connecting sleeve 5, X-type cross joint 6, suction sleeve 7, nozzle 9 and sand flushing nozzle 10 abut against each other. Sand flushing blind nozzle 14 is a sealing structure and can replace sand flushing nozzle 10 for installation.

[0035] The working principle of this utility model is as follows: The sand flushing device is placed at an appropriate position in the wellbore 1, and then power fluid is injected through the annular space between the outer pipe 2 and the inner pipe 3. The power fluid enters the second cavity 13 through the power fluid outlet hole 501 in the limiting connecting sleeve 5, and then enters the area between the nozzle 9 and the sand flushing nozzle 10 through the power fluid overflow hole 602 in the X-type cross joint 6. Then, part of it flushes the sand in the wellbore 1 through the sand flushing nozzle 10, and the other part enters the inner pipe 3 along the nozzle 9. When sand flushing is performed in the wellbore 1, the sand flushing generates... The mixture will enter the first cavity 702 through the mixture outlet hole 601 in the outer wall of the X-type cross joint 6, and then enter the area between the diffuser 8 and the nozzle 9 through the mixture suction hole 701. When the power fluid is injected, a portion of it will return through the nozzle 9, which will drive the mixture that has entered the area between the diffuser 8 and the nozzle 9 to be ejected from the inner tube 3. Secondly, the sand flushing nozzle 10 can be replaced with the sand flushing blind nozzle 14, because the sand flushing blind nozzle 14 will not flush the sand in the wellbore 1, so it only produces a suction effect and can be used for oil testing and gas testing.

[0036] In summary, this utility model, by setting up an inner pipe 3, an X-type cross joint 6, a suction sleeve 7, a diffuser pipe 8, and a nozzle 9, allows the power fluid to flow in two separate paths through the diffuser pipe 8 and the nozzle 9. The power fluid can drive the mixed liquid to be discharged, eliminating the need for an annular sealing unit during negative pressure sand flushing. This avoids the problem of easy blockage of the mixed sand fluid during annular backflow of the positive circulation jet pump. At the same time, it can continuously perform negative pressure sand flushing, reducing construction risks. By setting up a sand flushing blind nozzle 14, it can be used to achieve a suction function for oil and gas testing, improving well completion efficiency.

[0037] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A concentric coiled tubing reverse circulation jet pump negative pressure sand flushing device, comprising a wellbore (1), concentric double-tube coiled tubing, a reverse circulation jet pump, and a sand flushing device, characterized in that, The concentric double-tube continuous tubing includes an outer tube (2) and an inner tube (3) arranged coaxially; the bottom of the inner tube (3) is connected to a reverse-circulating jet pump, which includes a limiting connecting sleeve (5), an X-type cross joint (6) and a sand flushing nozzle (10); the bottom of the outer tube (2) is connected to a sand flushing device, which includes a suction sleeve (7), a diffuser (8) and a nozzle (9); the reverse-circulating jet pump and the sand flushing device are connected in parallel in the fluid circuit.

2. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 1, characterized in that, One end of the inner tube (3) is fitted with a diffuser tube (8), and the end of the outer tube (2) near the diffuser tube (8) abuts against the outer wall of the diffuser tube (8) through a limiting connecting sleeve (5); the outer side of the diffuser tube (8) is fitted with an inhalation sleeve (7) and an X-type cross connector (6) from the inside to the outside, and the same end of the inhalation sleeve (7) and the X-type cross connector (6) abuts against the limiting connecting sleeve (5) and forms a second cavity (13), and the other end is provided with a nozzle (9) installed on the inhalation sleeve (7) and a nozzle (9) installed on the X-type cross connector (6). The sand flushing nozzle (10) on the ) is provided with a first cavity (702) between the suction sleeve (7) and the X-type cross connector (6); the limiting connecting sleeve (5) is provided with a power fluid outlet hole (501) that connects to the second cavity (13); the X-type cross connector (6) and the suction sleeve (7) are respectively provided with a mixed liquid outlet hole (601) or a mixed liquid suction hole (701) that connects to the first cavity (702); the X-type cross connector (6) is provided with a power fluid flow hole (602) that connects to the second cavity (13).

3. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, The outer wall of the outer tube (2) is provided with a positioning ring (11), which is embedded in the wall of the outer tube (2) and extends to the outside. The limiting connecting sleeve (5) is fitted on the outer tube (2) and abuts against the positioning ring (11). A locking sleeve (4) is also fitted at the connection between the outer tube (2) and the limiting connecting sleeve (5).

4. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, The second cavity (13) is connected to the area between the outer tube (2) and the inner tube (3) through the power fluid outlet hole (501), and to the area between the nozzle (9) and the sand flushing nozzle (10) through the power fluid flow hole (602).

5. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, The first cavity (702) is connected to the inside of the wellbore (1) through the mixed liquid outflow hole (601) and to the area between the diffuser (8) and the nozzle (9) through the mixed liquid suction hole (701).

6. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, The diffuser tube (8) includes a wide-mouth end (801) and a narrow-mouth end (802). The wide-mouth end (801) is fitted in the inner tube (3), and the narrow-mouth end (802) is disposed in the inhalation sleeve (7).

7. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 1, characterized in that, The nozzle (9) includes a nozzle inlet (901) and a nozzle diffuser (902). The nozzle (9) is located at one end of the suction sleeve (7) near the sand flushing nozzle (10). The nozzle (9) has a nozzle inlet (901) at one end facing the suction sleeve (7) and a nozzle diffuser (902) at the other end.

8. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, The sand flushing nozzle (10) includes a sand flushing inlet (1001) and a sand flushing nozzle (1002). The sand flushing nozzle (10) is located at the end of the X-type cross joint (6) away from the outer tube (2) and is not in contact with the suction sleeve (7). The sand flushing nozzle (10) has a sand flushing inlet (1001) at one end near the nozzle (9) and a sand flushing nozzle (1002) at the other end.

9. The concentric continuous tubing reverse circulation jet pump negative pressure sand flushing device according to claim 2, characterized in that, In addition, it also includes a sealing ring (12) and a sand-flushing blind nozzle (14); the outer tube (2), locking sleeve (4), limiting connecting sleeve (5), X-type cross joint (6), suction sleeve (7), nozzle (9) and sand-flushing nozzle (10) are all provided with sealing rings (12) at the parts where they abut against each other; the sand-flushing blind nozzle (14) is a sealing structure, and the sand-flushing blind nozzle (14) can replace the sand-flushing nozzle (10) for installation.

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