A frequency-adjustable pulsed water jet device and its usage method

Abstract

This invention discloses a frequency-adjustable pulsed water jet device and its usage method, relating to the field of jet device technology. It solves the problems of poor frequency tuning accuracy and inconvenience of use of existing adjustable frequency jet nozzles, improves frequency tuning accuracy, and facilitates use. The specific solution is as follows: the first nozzle and the second nozzle are directly or through at least one prefabricated sub-cavity. The first nozzle is provided with a high-pressure water inlet and an abrasive inlet, and the second nozzle is provided with a water outlet. The side walls of the first nozzle, the second nozzle, and the sub-cavity are all provided with a plurality of threaded holes spaced circumferentially. The threaded holes are arranged along the axial direction of the first nozzle / second nozzle / sub-cavity and the threaded holes penetrate the corresponding second nozzle and sub-cavity. Bolts are screwed into the threaded holes of the second nozzle and sequentially connect the sub-cavity and the first nozzle.

Description

Technical Field

[0001] This invention relates to the field of jet device technology, and in particular to a frequency-adjustable pulsed water jet device and its usage method. Background Technology

[0002] High-pressure water jet rock breaking is widely used in underground space engineering construction due to its advantages such as low cost, cleanliness and environmental protection, high efficiency and dust-free operation. According to whether abrasive is added, high-pressure jet technology can be divided into abrasive jet and pure water jet. According to the jet form, it can be divided into continuous water jet and pulsed water jet. Since there is no stagnation pressure in pulsed jet, its rock breaking efficiency is 2-3 times that of continuous jet.

[0003] Since the pulse frequency has a significant impact on the rock-breaking effect during the pulsed water jet rock-breaking process, from the perspective of actual engineering needs, when facing constantly changing working conditions and strata, the frequency parameters of the pulsed water jet should be adjusted to adapt to the strata parameters, thereby improving the rock-breaking efficiency.

[0004] An existing self-vibrating jet nozzle with adjustable frequency (publication number CN115711134A) consists of upper and lower nozzles, with connectors mounted on the outer circumference of both nozzles. The two connectors are connected by bolts, and the axial cavity length can be adjusted by adjusting the distance between the two connectors. Although the jet frequency can be adjusted, the high pressure of the high-pressure water jet (pressure higher than 35MPa) makes the bolt connection prone to damage when the distance between the connectors is large. Furthermore, the upper and lower nozzles are connected by a plug-in method, making it difficult to guarantee airtightness and other requirements. The processing accuracy and cost are also high. In addition, the limited size of the upper and lower nozzles results in a limited cavity length and low overall adaptability. Changing the cavity length is achieved by manually moving the upper and lower nozzles, resulting in poor frequency tuning accuracy. Increasing the length of the upper and lower nozzles to increase the cavity length leads to the problem of inconvenience in carrying the nozzle. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a frequency-adjustable pulsed water jet device and its usage method. The length of the self-vibrating cavity is adjusted by changing the number and length of the sub-cavities. The sub-cavities can be prefabricated, which facilitates use and ensures frequency tuning accuracy. This solves the problems of poor frequency tuning accuracy and inconvenience in use of existing adjustable frequency jet nozzles.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a frequency-adjustable pulsed water jet device, including a first nozzle and a second nozzle, wherein the first nozzle and the second nozzle form a self-vibrating cavity, and the first nozzle and the second nozzle are directly or through at least one prefabricated sub-cavity. The first nozzle is provided with a high-pressure water inlet and an abrasive inlet, and the second nozzle is provided with a water outlet. The sidewalls of the first nozzle, the second nozzle, and the sub-cavity are all provided with a plurality of threaded holes spaced circumferentially, the threaded holes are arranged along the axial direction of the first nozzle / second nozzle / sub-cavity and the threaded holes penetrate the corresponding second nozzle and sub-cavity. Bolts are screwed into the threaded holes of the second nozzle and sequentially connect the sub-cavity and the first nozzle.

[0008] As a further implementation, the number of threaded holes on the first nozzle, the second nozzle, and the sub-cavity are the same and correspond one-to-one.

[0009] As a further implementation, the first nozzle is provided with a gemstone mounting position, which is located at the center of the first nozzle along with the high-pressure water inlet. A gemstone for preventing backflow is installed on the gemstone mounting position, and the abrasive inlet is located on the side wall of the first nozzle.

[0010] As a further implementation, the gemstone is provided with several through holes with a diameter smaller than that of the water outlet.

[0011] As a further implementation, the inner wall of the end of the second nozzle with the water outlet gradually decreases in height from the water outlet location toward the direction away from the water outlet.

[0012] As a further implementation, the first nozzle and the sub-cavity, adjacent sub-cavities, and the sub-cavity and the second nozzle, or the first nozzle and the second nozzle, are all connected and fitted by protrusion and groove structures.

[0013] As a further implementation, a rubber sealing structure is provided at the mating point of the protrusion and the groove.

[0014] As a further implementation, when the total cavity length L of the self-vibrating cavity is less than 30 mm, the length of each sub-cavity is no more than 5 mm; when the total cavity length L is greater than 30 mm, the length of each sub-cavity is no less than 5 mm and no more than 10 mm.

[0015] Secondly, the present invention provides a method for using a frequency-adjustable pulsed water jet device, as detailed below:

[0016] First, determine the required jet pulse frequency based on the formation parameters;

[0017] The total cavity length of the required self-resonating cavity is calculated based on the determined jet pulse frequency;

[0018] After determining the total length of the self-vibrating cavity, select sub-cavities of appropriate length and number to connect the first nozzle and the second nozzle.

[0019] As a further implementation, during assembly, the sub-cavity is placed between the first nozzle and the second nozzle, so that the threaded holes on the first nozzle, the second nozzle, and the sub-cavity correspond one-to-one and are coaxially arranged and screwed in with bolts for fixation.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) This invention utilizes the number and length of the sub-cavities to change the total length of the self-vibrating cavity, thereby changing the pulse frequency and making the frequency of the jet close to the natural frequency of the rock mass. This causes the rock mass to resonate under the excitation of the pulsed water jet, thereby improving the rock-breaking effect of the high-pressure pulsed water jet. The sub-cavities are prefabricated structures, which are convenient for storage and use. The length of the self-vibrating cavity is precisely controlled by the length of the sub-cavities, which solves the problem that traditional pulsed water jet nozzles cannot accurately and quickly change the pulse parameters when facing different working conditions, thus leading to low rock-breaking efficiency of pulsed water jets.

[0022] (2) The present invention has threaded holes directly opened on the side walls of the sub-cavity, the first nozzle and the second nozzle and is fixedly connected by bolts. There are no ear plate-type connecting parts between the first nozzle and the second nozzle. No matter how the cavity length changes, the first nozzle and the second nozzle are connected through the sub-cavity. The connection firmness and sealing performance will not change, and the device has high reliability. At the same time, the sub-cavity, the first nozzle and the second nozzle are all fitted by protrusions and grooves, which effectively ensures the sealing performance.

[0023] (3) The present invention limits the length of a single sub-cavity under different cavity lengths. On the one hand, the sub-cavities can be prefabricated, and when in use, the corresponding length and number of sub-cavities can be selected according to the required jet frequency, which greatly improves the assembly efficiency. On the other hand, the total cavity length can be determined according to the required jet frequency, and the corresponding length of the sub-cavities can be selected according to the total cavity length. When the total cavity length L < 30 mm, the frequency adjustment will not be inaccurate due to the excessive length of the sub-cavities. When the total cavity length L > 30 mm, too many sub-cavities will not be used. This not only ensures the accuracy of frequency adjustment, but also facilitates storage and use. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic cross-sectional view of an adjustable frequency pulsed water jet device according to one or more embodiments of the present invention.

[0026] Figure 2This is a top view of the sub-cavity structure according to one or more embodiments of the present invention;

[0027] Figure 3 This is a schematic diagram illustrating the relationship between cavity length and pulse frequency according to one or more embodiments of the present invention;

[0028] In the diagram: the spacing or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0029] Among them, 1. First nozzle; 2. Second nozzle; 3. Sub-cavity; 4. Gemstone; 5. Abrasive inlet; 6. High-pressure water inlet; 7. Threaded hole; 8. Water outlet. Detailed Implementation

[0030] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] As described in the background section, existing frequency-adjustable self-vibrating jet nozzles consist of upper and lower nozzles, with connectors mounted on the outer circumference of both nozzles. These connectors are bolted together, and the axial cavity length can be adjusted by changing the distance between them. While this allows for frequency adjustment, the high pressure of the high-pressure water jet (above 35 MPa) easily damages the bolted connections. Furthermore, the insert-type connection between the upper and lower nozzles makes it difficult to guarantee airtightness, resulting in high processing precision and cost. Additionally, the limited size of the upper and lower nozzles leads to a limited cavity length, resulting in low overall adaptability. Changing the cavity length requires manually moving the nozzles, leading to poor frequency tuning accuracy. Increasing the length of the upper and lower nozzles to improve the cavity length causes inconvenience in carrying the nozzle. To address these technical problems, this invention proposes a frequency-adjustable pulsed water jet device and its usage method.

[0032] Example 1

[0033] In a typical embodiment of the present invention, such as Figures 1-3 As shown, a frequency-adjustable pulsed water jet device is proposed, comprising a first nozzle 1, a second nozzle 2, and a plurality of sub-cavities 3. The first nozzle 1 and the second nozzle 2 are directly connected or connected through at least one sub-cavity 3 to form a jet device. The axial cavity length of the jet device can be adjusted by changing the length and / or number of sub-cavities 3.

[0034] The first nozzle 1, the second nozzle 2, and the sub-cavity are all annular structures and each contains a chamber. The first nozzle 1 and the second nozzle 2 form a self-vibrating cavity. The side walls of the first nozzle 1, the second nozzle 2, and the sub-cavity 3 are all provided with a number of threaded holes 7 at intervals along their respective circumferential directions. The threaded holes 7 are arranged along the axial direction of the first nozzle 1 / second nozzle 2 / sub-cavity 3. The number of threaded holes 7 on the first nozzle 1, the second nozzle 2, and the sub-cavity 3 is the same and they correspond one-to-one.

[0035] The threaded hole 7 passes through the corresponding second nozzle 2 and sub-cavity 3, so that during actual installation, a bolt of a set length is inserted into the threaded hole 7 of the second nozzle 2 and sequentially connects the sub-cavity 3 and the first nozzle 1.

[0036] The sub-cavity 3 can be configured such that when the axial cavity length needs to be changed, the number and / or length of the sub-cavities 3 can be changed. The sub-cavities 3 can be prefabricated, making them convenient to use. Moreover, the dimensions of the sub-cavities 3 are fixed, which facilitates the control of the cavity length and ensures high frequency tuning accuracy. In addition, there are no connecting parts (such as ear plates) between the first nozzle 1 and the second nozzle 2. No matter how the cavity length changes, the first nozzle 1 and the second nozzle 2 are connected through the sub-cavities 3, and the connection strength and sealing performance will not change.

[0037] The first nozzle 1 has a gemstone mounting position, a high-pressure water inlet 6, and an abrasive inlet 5. The gemstone mounting position and the high-pressure water inlet 6 are both located at the center of the first nozzle 1. The gemstone mounting position is used to install the gemstone 4. The gemstone mounting position and the high-pressure water inlet 6 are coaxially arranged. The jet water passes through the gemstone 4 and enters the high-pressure water inlet 6. The gemstone 4 plays a role in preventing backflow.

[0038] The abrasive inlet 5 is located on the side wall of the first nozzle 1. The angle between the axis of the abrasive inlet 5 and the axis of the high-pressure water inlet 6 is an acute angle. The abrasive inlet 5 is connected to the chamber of the first nozzle 1. After the high-pressure water enters the chamber of the first nozzle 1, a negative pressure is formed due to the flow velocity. Under the action of the negative pressure, the abrasive enters the chamber of the first nozzle 1 through the abrasive inlet 5. The abrasive and the water jet mix in the chamber to form a high-pressure pulsed abrasive water jet.

[0039] The gem 4 is provided with several through holes evenly distributed to allow the jet water to pass through; the second nozzle 2 is provided with a water outlet 8, the diameter of which is several times the diameter of the through holes on the gem 4, which is three times in this embodiment, so as to facilitate the control of the flow rate and ensure the formation of negative pressure in the chamber.

[0040] The outlet 8 is located at the center of the second nozzle 2. The inner wall of the end of the second nozzle 2 with the outlet 8 gradually decreases in height from the outlet 8 towards the direction away from the outlet 8, so as to form a collision wall structure that is high in the middle and low on the periphery. After the high-pressure water jet generates a pulse effect in the chamber, it is ejected from the outlet 8.

[0041] The first nozzle 1 and the sub-cavity 3, adjacent sub-cavities 3, and the sub-cavity 3 and the second nozzle 2, or the first nozzle 1 and the second nozzle 2, are all connected by a protrusion and groove structure. For example, the end of the first nozzle 1 connected to the sub-cavity 3 has a groove along its circumference; one end of the sub-cavity 3 has a protrusion and the other end has a groove; the end of the second nozzle 2 connected to the sub-cavity 3 has a protrusion, so that they can be inserted together in sequence to ensure the sealing of the end connection.

[0042] It is understood that the protrusions and grooves are not limited to the above description. Protrusions can also be provided at the end of the first nozzle 1 that is connected to the sub-cavity 3. The specific setting method can be determined according to the actual design requirements. No further restrictions are imposed here.

[0043] To improve the sealing performance of the connection between the first nozzle 1, the second nozzle 2, and the sub-cavity 3, rubber sealing structures such as sealing rings can be installed at the mating points of the protrusions and grooves.

[0044] The cavity length (axial length of the self-oscillating cavity) of the jet device can be calculated using the cavity length formula, as follows:

[0045]

[0046] Where D represents the cavity diameter of the self-oscillating cavity; L represents the axial cavity length of the self-oscillating cavity; f represents the pulse frequency of the jet; N represents the mode number, N = 1, 2, 3…; U c d1 represents the convection velocity of the jet in the cavity; d1 represents the diameter of the upstream nozzle; λ represents the wavelength of the sound wave.

[0047] During use, the target cavity length is first calculated according to formula (1). Then, the number and / or length of the sub-cavities 3 are changed to complete the assembly of the pulse nozzles. After reinforcement and sealing, the water pump and abrasive are turned on. High-pressure water enters through the first nozzle 1, and the abrasive enters through the abrasive inlet 5 under negative pressure. At this time, the abrasive and water jet mix in the cavity to form a high-pressure pulsed abrasive water jet. When the rock breaking efficiency decreases due to changes in strata or lithology, and the pulse frequency needs to be adjusted, the cavity length is recalculated according to formula (1). Then, the number and / or length of the sub-cavities 3 are changed to meet the calculated cavity length.

[0048] like Figure 3 The influence of cavity length on frequency is shown. When the total cavity length is greater than 30 mm, the sensitivity of jet frequency change to the influence of cavity length is much smaller than when the total cavity length is less than 30 mm. Therefore, based on the above principle, this embodiment limits the length of a single sub-cavity 3, specifically as follows:

[0049] When the total cavity length L < 30 mm, the design length of each sub-cavity 3 shall not exceed 5 mm; when the total cavity length L > 30 mm, the design length of each sub-cavity 3 shall not be less than 5 mm and not more than 10 mm.

[0050] Understandably, the specific length of the sub-cavity 3 can be determined according to the actual design requirements. In practical applications, sub-cavities 3 of each length can be manufactured so that different lengths of sub-cavities 3 can be selected for use according to actual needs, thereby improving ease of use.

[0051] By limiting the length of the sub-cavity 3 as described above, the sub-cavity 3 can be prefabricated. When in use, the corresponding length and number of sub-cavities 3 can be selected according to the required jet frequency, which not only makes it convenient to carry but also easy to use and improves assembly efficiency.

[0052] On the other hand, the total cavity length can be determined according to the required jet frequency, and a sub-cavity 3 of corresponding length can be selected according to the total cavity length. When the total cavity length L < 30mm, the frequency adjustment will not be inaccurate due to the excessive length of the sub-cavity 3. When the total cavity length L > 30mm, too many sub-cavities 3 will not be used. This not only ensures the accuracy of frequency adjustment, but also facilitates storage and use.

[0053] Example 2

[0054] In a typical embodiment of the present invention, a method for using a frequency-adjustable pulsed water jet device is provided, as detailed below:

[0055] First, determine the actual required jet pulse frequency based on the formation parameters;

[0056] Then, based on the determined jet pulse frequency, the total cavity length of the self-vibrating cavity of the jet device is calculated using the cavity length formula (1);

[0057] After determining the total length of the self-vibrating cavity, select sub-cavities 3 of appropriate length and number to connect the first nozzle 1 and the second nozzle 2.

[0058] Specifically, when the total cavity length L < 30 mm, the length of each selected sub-cavity 3 shall not exceed 5 mm; when the total cavity length L > 30 mm, the length of each selected sub-cavity 3 shall not be less than 5 mm and not more than 10 mm.

[0059] During assembly, the sub-cavity 3 is placed between the first nozzle 1 and the second nozzle 2, so that the first nozzle 1, the second nozzle 2 and the threaded holes 7 on the sub-cavity 3 correspond one-to-one and are coaxially arranged, and the bolts are screwed into the threaded holes 7 to fix the connection.

[0060] Understandably, when the total cavity length does not need to be changed using the sub-cavity 3, the first nozzle 1 and the second nozzle 2 can be directly connected using bolts.

[0061] By varying the number and length of the sub-cavities 3, the total length of the self-vibrating cavity is altered, thereby changing the pulse frequency. This brings the jet frequency closer to the natural frequency of the rock mass, causing the rock mass to resonate under the excitation of the pulsed water jet, thus enhancing the rock-breaking effect of the high-pressure pulsed water jet. This solves the problem of traditional pulsed water jet nozzles being unable to accurately and quickly change pulse parameters under different working conditions, leading to low rock-breaking efficiency. Furthermore, the jet device described in this embodiment is suitable for continuous and stable operation of pulse nozzles under high and ultra-high pressure conditions, and the modular design solves the problem of poor sealing.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A frequency tunable pulsed water jet device comprising a first nozzle and a second nozzle, a self-oscillating cavity being formed between the first nozzle and the second nozzle, characterized in that, The first nozzle is connected with the second nozzle directly or through at least one prefabricated sub-cavity, the first nozzle is provided with a high-pressure water inlet and an abrasive inlet, the second nozzle is provided with a water outlet, a plurality of threaded holes are arranged on the side walls of the first nozzle, the second nozzle and the sub-cavity in a ring direction, the threaded holes are arranged along the axial direction of the first nozzle / second nozzle / sub-cavity and penetrate the corresponding second nozzle and sub-cavity, and the threaded holes are screwed into the threaded holes of the second nozzle and sequentially connect the sub-cavity and the first nozzle through bolts. The specific length of the sub-cavity can be determined according to actual design requirements, and sub-cavities of each length are fabricated to select sub-cavities of different lengths for use according to actual needs. When the total cavity length L of the self-vibration cavity is less than 30 mm, the length of each sub-cavity is not greater than 5 mm; when the total cavity length L is greater than 30 mm, the length of each sub-cavity is not less than 5 mm and not greater than 10 mm. Through the above limitation of the length of the sub-cavity, the sub-cavity can be prefabricated, and in use, sub-cavities of corresponding lengths and quantities can be selected according to the required jet frequency; or the total cavity length can be determined according to the required jet frequency, and sub-cavities of corresponding lengths can be selected according to the total cavity length. The cavity length of the jet device can be calculated according to the cavity length formula, and the calculation formula is as follows: ， wherein, represents the cavity length of the self-resonating cavity; L represents the axial cavity length of the self-resonating cavity; f represents the pulse frequency of the jet; N represents the mode number; U c represents the convection velocity of the jet in the cavity; d 1 represents the diameter of the upstream nozzle; The number of threaded holes on the first nozzle, the second nozzle and the sub-cavity is the same and one-to-one corresponding. represents the wavelength of the acoustic wave.

2. A frequency tunable pulsed water jet device according to claim 1, characterized in that The first nozzle is provided with a gem mounting position, the gem mounting position and the high-pressure water inlet are located at the center position of the first nozzle, a gem for preventing backflow is mounted on the gem mounting position, and the abrasive inlet is arranged on the side wall of the first nozzle.

3. A frequency tunable pulsed water jet device according to claim 1, characterized in that The gem is provided with a plurality of through holes with diameters smaller than the water outlet.

4. A frequency tunable pulsed waterjet device according to claim 3, characterized in that The inner wall of the end of the second nozzle provided with the water outlet gradually decreases in height from the water outlet position to the direction away from the water outlet.

5. A frequency tunable pulsed water jet device according to claim 1, characterized in that The first nozzle and the sub-cavity, adjacent sub-cavities, and the sub-cavity and the second nozzle or the first nozzle and the second nozzle are all connected through protrusion and groove structure plug-in cooperation.

6. A frequency tunable pulsed water jet device according to claim 1, characterized in that The matching part of the protrusion and the groove is provided with a rubber sealing structure.

7. A frequency tunable pulsed waterjet device according to claim 6, characterized in that Specifically as follows:

8. A method of using a frequency adjustable pulsed water jet device as claimed in any one of claims 1-7, characterized in that, First, determine the required jet pulse frequency according to the formation parameters; The total cavity length of the self-vibration cavity is calculated according to the determined jet pulse frequency; After the total cavity length of the self-vibration cavity is determined, the first nozzle and the second nozzle are connected by selecting sub-cavities of appropriate length and quantity. In assembly, the sub-cavities are placed between the first nozzle and the second nozzle, so that the threaded holes on the first nozzle, the second nozzle and the sub-cavities are one-to-one corresponding and coaxially arranged and screwed into the bolts for fixation.

9. A method of using a frequency tunable pulsed waterjet device according to claim 8, characterized in that, ​

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