An underwater free-field pressure sensor impact calibration device

Abstract

The application discloses an underwater free field pressure sensor impact calibration device to solve the problems of complex process, high cost, incapability of containing complete sensors and low calibration efficiency of existing calibration devices. Specifically, the device comprises a support, a calibration oil cavity arranged at the bottom of the support, a lifting rope driving control mechanism arranged at the top of the support, a drop hammer arranged between the calibration oil cavity and the lifting rope driving control mechanism and a lifting rope. The upper end of the lifting rope is connected with the driving end of the lifting rope driving control mechanism, and the lower end is connected with the top of the drop hammer. The lower end of the drop hammer corresponds to the top end of the calibration oil cavity. A standard sensor is installed on the outer wall of the calibration oil cavity, and the top edge is used for installing a sensor to be calibrated.

Description

Technical Field

[0001] This invention relates to sensor calibration devices, specifically to an impact calibration device for an underwater free-field pressure sensor. Background Technology

[0002] Compared to traditional underwater pressure sensors, underwater free-field pressure sensors have a more specialized encapsulation (such as silicone oil encapsulation). The sensing element is unaffected by boundaries and mounting fixtures, and it senses the free-field pressure signal. Underwater free-field pressure sensors typically have a slender tubular structure, unlike traditional pressure sensors. Therefore, traditional oil-filled pressure sensor calibration devices are unsuitable for underwater free-field pressure sensors. A common calibration method is pre-shipment calibration—calibrating the sensing element. However, this requires a series of steps, including sensor disassembly, sensing element removal, sensing element calibration, and post-calibration encapsulation. Each step requires specialized equipment, which most sensor users lack. Therefore, this method usually results in the sensor being returned to the factory. In summary, existing underwater free-field pressure sensor calibration methods have the following problems:

[0003] (1) The sensor needs to be disassembled, the process is complex and the requirements are high, the calibration cost is high and the cycle is long;

[0004] (2) Existing traditional oil chamber pressure sensor calibration devices cannot accommodate complete underwater free field pressure sensors, and the calibration environment cannot simulate the real working environment.

[0005] (3) The calibration efficiency is low and the operation is inconvenient. Summary of the Invention

[0006] The purpose of this invention is to provide an impact calibration device for an underwater free-field pressure sensor, so as to solve the technical problems of complex procedures, high cost and low calibration efficiency in existing calibration methods.

[0007] To achieve the above objectives, the present invention provides an impact calibration device for an underwater free field pressure sensor, which is characterized by including a bracket, a calibration oil chamber disposed at the bottom of the bracket, a suspension rope drive control mechanism disposed at the top of the bracket, a drop hammer disposed between the calibration oil chamber and the suspension rope drive control mechanism, and a suspension rope.

[0008] The upper end of the suspension rope is connected to the drive end of the suspension rope drive control mechanism, and the lower end is connected to the top of the drop hammer.

[0009] The lower end of the drop hammer corresponds to the top end of the calibration oil chamber;

[0010] The outer wall of the calibration oil chamber is used to install standard sensors and sensors to be calibrated.

[0011] Furthermore, the calibration oil chamber includes a chamber body, a sensor mounting assembly, an oil chamber cover, and a piston;

[0012] The cavity body is cylindrical, with a central oil injection hole with a closed bottom along its center along the axial direction. Multiple branch holes with closed bottoms are evenly distributed around the central oil injection hole along its circumference. Each branch hole has a connecting hole with the central oil injection hole for communication. The distance between the central axis of the connecting hole and the bottom surface of the branch hole is greater than or equal to the axial length from the tip of the sensitive element of the sensor to be calibrated to the tip of the entire sensor. At least one of the branch holes has a standard mounting hole on its outer wall connecting to the outside world. The standard mounting hole is used to install a standard sensor. The branch hole is used to install the sensor to be calibrated through the sensor mounting assembly, and the branch hole is equipped with an oil cavity cap. The oil cavity cap is used to seal the top of the branch hole when no sensor to be calibrated is installed. The piston is used to block the top of the central oil injection hole. The central oil injection hole and the branch holes are filled with oil.

[0013] Furthermore, the top height of the branch hole is lower than the top height of the central oil injection hole.

[0014] Furthermore, the height difference between the top of the branch hole and the central oil injection hole ranges from 5 to 20 millimeters.

[0015] Furthermore, an overflow valve is provided at the center of the oil cavity cover; the overflow valve is threadedly sealed to the oil cavity cover.

[0016] The piston has an exhaust valve at its center; the exhaust valve is threadedly sealed to the piston.

[0017] Furthermore, this also includes pressure plugs;

[0018] Each of the branch holes has a standard mounting hole on its outer wall; the pressure plug is used to block the standard mounting hole where no standard sensor is installed.

[0019] Furthermore, the sensor mounting assembly includes a sealing sleeve, a sensor cover, and a sealing nut;

[0020] The sealing sleeve is fitted onto the cable of the sensor to be calibrated and passes through the axial central through hole of the sensor cover; the inner diameter of the central through hole is larger than the maximum outer diameter of the sensor to be calibrated.

[0021] The lower end of the sensor cover extends into the top of the branch hole and is threadedly sealed with the cavity body. Its upper end is provided with a tapered claw thread with the small end facing upward.

[0022] The sealing nut is fitted onto the cable of the sensor to be calibrated and the tapered claw thread on the upper end of the sensor cover. The sealing is achieved by rotating the sealing nut to compress the sealing sleeve.

[0023] Furthermore, the axes of the branch holes and the central oil injection holes are parallel to each other;

[0024] The axes of the connecting hole and the standard mounting hole are both perpendicular to the axis of the central oil injection hole; and the axes of the connecting hole and the standard mounting hole are at the same height.

[0025] Furthermore, the bracket includes a base and two optical axes;

[0026] The base is disc-shaped, with the center used to place the calibration oil chamber;

[0027] The two optical axes are located on the radial sides of the calibration oil chamber, with the lower end of each optical axis connected to the base and the upper end connected to the suspension rope drive control mechanism, such that the drive end of the suspension rope drive control mechanism is located between the two optical axes and is opposite to the central axis of the calibration oil chamber.

[0028] Furthermore, the drop hammer has symmetrical lugs on both sides; each of the two lugs is mounted on the outside of the two optical axes via a linear bearing;

[0029] The base is provided with a positioning groove; the bottom of the cavity body is provided with a positioning protrusion; the positioning groove and the positioning protrusion engage to achieve positioning.

[0030] The lower end of the suspension rope is connected to the center of the top of the drop hammer via a suspension rope nut;

[0031] The linear bearing is interference-fitted with the lug.

[0032] The beneficial effects of this invention are:

[0033] 1. This invention adopts the "comparison" calibration principle and designs a calibration oil chamber that can accommodate a standard sensor and a sensor to be calibrated. Impact pressure is generated in the calibration oil chamber by impacting and compressing it with a drop hammer. The sensitive elements of the standard pressure sensor and the sensor to be calibrated are in the same physical position, which minimizes the error caused by structural differences. The structure is simple, the cost is low, and the calibration efficiency is high.

[0034] 2. The calibration oil chamber of this invention adopts a design with a central oil injection hole and multiple branch holes evenly distributed around the central oil injection hole. The branch holes can completely accommodate the slender sensor to be calibrated, eliminating the need for disassembly. Simultaneously, it can simulate the real working environment of the pressure sensor to the greatest extent, reducing errors caused by structural differences and making the calibration results more reliable. Furthermore, it can calibrate multiple pressure sensors simultaneously, resulting in high calibration efficiency.

[0035] 3. The oil chamber of the present invention has multiple circumferential branch holes with the same physical structure. The sensor to be calibrated is installed from the top, and the standard sensor is installed in the branch hole. Each hole can simultaneously or separately install the sensor to be calibrated and the standard sensor. It is possible to select the scheme that makes the pressure of the sensor to be calibrated and the standard sensor closest as needed, thereby improving the calibration accuracy.

[0036] 4. The present invention provides a connecting hole between the branch hole and the central oil injection hole, which adopts the principle of communicating vessels to reduce the inconvenience caused by oil leakage.

[0037] 5. The central oil injection hole and the circumferentially distributed branch holes of the present invention adopt the principle of communicating vessels. The top of the central oil injection hole is higher than the top of the branch holes. At the same time, the branch holes are equipped with overflow valves, and the piston in the central oil injection hole is equipped with an exhaust valve, which can maximize the filling of the branch holes with oil and ensure the accuracy of the calibration results.

[0038] 6. The height difference between the top of the central oil injection hole and the branch hole of the present invention is 5-20 mm, so that the upper ends of the central oil injection hole and the branch hole are basically flat. This results in very little oil leakage during the disassembly and assembly of the sensor to be calibrated, increasing the convenience of operation and improving work efficiency.

[0039] 7. The present invention provides standard mounting holes on the sidewall of each branch hole. During calibration, multiple standard sensors can be installed simultaneously to reduce measurement errors and improve measurement accuracy. In addition, different numbers of standard sensors can be installed according to different working conditions to improve the applicability of the calibration device. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of an embodiment of an underwater free-field pressure sensor impact calibration device according to the present invention;

[0041] Figure 2 yes Figure 1 Exploded view;

[0042] Figure 3 This is a cross-sectional view of the calibration oil cavity in an embodiment of the present invention.

[0043] Icon labels:

[0044] 1-Calibration oil chamber, 2-Base, 3-Optical axis, 4-Linear bearing, 5-Drop hammer, 6-Hanging rope nut, 7-Hanging rope, 8-Hanging rope drive control mechanism, 11-Cavity body, 12-Sensor mounting assembly, 13-Standard sensor, 14-Pressure plug, 15-Oil chamber cover, 16-Overflow valve, 17-Piston, 18-Exhaust valve, 111-Center oil injection hole, 112-Connecting hole, 113-Branch hole, 121-Sensor to be calibrated, 122-Sealing sleeve, 123-Sensor cover, 124-Sealing nut. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] An embodiment of the present invention provides an impact calibration device for an underwater free-field pressure sensor, such as... Figure 1 and Figure 2 As shown, the calibration device includes a calibration oil chamber 1, a base 2, an optical axis 3, a linear bearing 4, a drop hammer 5, a suspension rope nut 6, a suspension rope 7, and a suspension rope drive control mechanism 8.

[0047] The calibration oil chamber 1 includes a chamber body 11, a sensor mounting assembly 12, a standard sensor 13, a pressure plug 14, an oil chamber cover 15, an overflow valve 16, a piston 17, and an exhaust valve 18.

[0048] like Figure 3 As shown, the cavity body 11 has a vertically arranged central oil injection hole 111 and multiple branch holes 113 arranged circumferentially around the central oil injection hole 111 and also arranged vertically. The length of the branch holes 113 is greater than the length of the sensor to be calibrated 121. The main body of the sensor assembly 12 to be calibrated is placed therein. The central oil injection hole 111 and the branch holes 113 are connected by a horizontally arranged connecting hole 112. The height of the connecting hole 112 relative to the bottom of the branch holes 113 is the same as the height from the tip of the sensitive element of the sensor to be calibrated 121 to the bottom of the entire sensor to be calibrated 121, or it can be slightly greater.

[0049] The central oil injection hole 111 is fitted with the piston 17, which can move downward to compress the oil chamber under the impact of the drop hammer 5; the branch hole 113 is threadedly sealed with the oil chamber cover 15 and the sensor assembly to be calibrated 12; the upper port of the central oil injection hole 111 is slightly higher than the upper port of the branch hole 113, and according to the principle of communicating vessels, the branch hole 113 can be filled with oil to the maximum extent.

[0050] The branch hole 113 is located on the outside of the cavity body 11, and its outer wall is provided with a radial standard mounting hole at the same height as the connecting hole 112, which is used to make threaded sealing fit with the standard sensor 13 or the pressure plug 14.

[0051] The overflow valve 16 is threadedly sealed to the oil chamber cover 15 to ensure that the branch hole 113 is filled with oil. The vent valve 18 is threadedly sealed to the center hole of the piston 17 to discharge gas from the center oil injection hole 111.

[0052] The sensor mounting assembly 12 includes a sealing sleeve 122, a sensor cover 123, and a sealing nut 124. The sealing sleeve 122 has a flexible opening design, which can be fitted onto the cable of the sensor 121, inserted into the central hole of the sensor cover 123, and tightened to seal by the sealing nut 124. The upper outer side of the central hole of the sensor cover 123 has a tapered claw-shaped thread. As the sealing nut 124 is tightened, the tapered claw-shaped thread converges to seal the cable of the sensor 121 covered by the sealing sleeve 122. The lower outer thread of the central hole of the sensor cover 123 is in sealing engagement with the thread on the inner wall of the top of the branch hole 113. The diameter of the central boss inside the central hole of the sensor cover 123 is larger than the diameter of the sensor 121 to be calibrated, ensuring that the sensor 121 to be calibrated can be installed smoothly.

[0053] The two optical axes 3 are fixed by bolts through the holes on both sides of the base 2. The central positioning groove of the base 2 and the bottom positioning protrusion of the calibration oil chamber 1 are matched to achieve the center positioning of the calibration oil chamber 1 and the piston 17.

[0054] The drop hammer 5 has a truncated cone structure at its center and lugs on both sides. The lugs have ear holes that are interference-fitted with linear bearings 4. Linear bearings 4 are mounted on optical shaft 3 and cooperate with optical shaft 3, allowing the drop hammer 5 to move freely up and down along optical shaft 3. The center hole at the upper end of the drop hammer 5 cooperates with the suspension nut 6 to fix the suspension rope 7 to the center of the upper end of the drop hammer 5. The upper end of the suspension rope 7 is connected to the drive end of the suspension rope drive control mechanism 8 to control the rise and fall of the drop hammer 5.

[0055] This invention employs a "comparative" calibration principle, where a falling hammer 5 impacts the piston 17 to generate pulse pressure in the oil chamber. The oil chamber features a central oil injection hole 111 and multiple circumferentially distributed branch holes 113. The slender tube sensor 12 to be calibrated is completely accommodated within the branch holes. The sensitive elements of the standard sensor 13 and the sensor 12 to be calibrated are located in the same circumferential physical position, minimizing errors caused by structural differences. The central oil injection hole 111 and the branch holes 113 utilize the principle of communicating vessels, with the openings located on the upper end face, reducing inconvenience caused by oil leakage during sensor installation. The oil chamber has multiple branch holes 113, allowing for the simultaneous calibration of multiple pressure sensors, resulting in high calibration efficiency.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An impact calibration device for an underwater free-field pressure sensor, characterized in that: It includes a support, a calibration oil chamber (1) located at the bottom of the support, a suspension rope drive control mechanism (8) located at the top of the support, a drop hammer (5) located between the calibration oil chamber (1) and the suspension rope drive control mechanism (8), and a suspension rope (7); The upper end of the suspension rope is connected to the drive end of the suspension rope drive control mechanism (8), and the lower end is connected to the top of the drop hammer (5); the lower end of the drop hammer (5) corresponds to the top of the calibration oil chamber (1); the outer wall of the calibration oil chamber (1) is used to install the standard sensor (13) and the sensor to be calibrated (121). The calibration oil chamber (1) includes a chamber body (11), a sensor mounting assembly (12), an oil chamber cover (15), and a piston (17). The chamber body (11) is cylindrical, with a bottom-closed central oil injection hole (111) at its center along the axial direction. Multiple bottom-closed branch holes (113) are evenly distributed around the central oil injection hole (111) along its edge. Each branch hole (113) is connected to the central oil injection hole (111) via a connecting hole (112). The distance between the central axis of the connecting hole (112) and the bottom surface of the branch hole (113) is greater than or equal to the distance from the tip of the sensitive element of the sensor (121) to the entire length of the sensor (121). The axial length of the tip of the body; at least one of the branch holes (113) has a standard mounting hole on its outer wall that connects to the outside world and the branch hole (113); the standard mounting hole is used to install a standard sensor (13); the branch hole (113) is used to install a sensor to be calibrated (121) through the sensor mounting assembly (12), and the branch hole (113) is equipped with the oil chamber cover (15), the oil chamber cover (15) is used to seal the top of the branch hole (113) when the sensor to be calibrated (121) is not installed; the piston (17) is used to block the top of the central oil injection hole (111); the central oil injection hole (111) and the branch hole (113) are filled with oil; The axis of the branch hole (113) is parallel to that of the central oil injection hole (111); the axis of the connecting hole (112) and the standard mounting hole are both perpendicular to the axis of the central oil injection hole (111); and the axis of the connecting hole (112) and the standard mounting hole are at the same height.

2. The underwater free-field pressure sensor impact calibration device according to claim 1, characterized in that: The top height of the branch hole (113) is lower than the top height of the central oil injection hole (111).

3. The underwater free-field pressure sensor impact calibration device according to claim 2, characterized in that: The height difference between the top of the branch hole (113) and the central oil injection hole (111) ranges from 5 to 20 mm.

4. The underwater free-field pressure sensor impact calibration device according to claim 1, 2, or 3, characterized in that: An overflow valve (16) is provided at the center of the oil chamber cover (15); the overflow valve (16) is threadedly sealed to the oil chamber cover (15); The piston (17) is provided with an exhaust valve (18) at its center; the exhaust valve (18) is threadedly sealed to the piston (17).

5. The underwater free-field pressure sensor impact calibration device according to claim 4, characterized in that: It also includes pressure plugs (14); The outer wall of each branch hole (113) is provided with a standard mounting hole; the pressure plug (14) is used to block the standard mounting hole where the standard sensor (13) is not installed.

6. The underwater free-field pressure sensor impact calibration device according to claim 5, characterized in that: The sensor mounting assembly (12) includes a sealing sleeve (122), a sensor cover (123), and a sealing nut (124). The sealing sleeve (122) is fitted onto the cable of the sensor (121) to be calibrated and passes through the axial central through hole of the sensor cover (123); the inner diameter of the central through hole is larger than the maximum outer diameter of the sensor (121) to be calibrated. The lower end of the sensor cover (123) extends into the top of the branch hole (113) and is threadedly sealed with the cavity body (11). Its upper end is provided with a tapered claw thread with the small end facing upward. The sealing nut (124) is fitted onto the cable of the sensor to be calibrated (121) and the tapered claw thread on the upper end of the sensor cover (123). As the sealing nut (124) is tightened, the tapered claw thread can converge to seal the cable of the sensor to be calibrated (121) covered with the sealing sleeve (122).

7. The underwater free-field pressure sensor impact calibration device according to claim 6, characterized in that: The bracket includes a base (2) and two optical axes (3); The base (2) is disc-shaped, and its center is used to place the calibration oil chamber (1). The two optical axes (3) are located on the radial sides of the calibration oil chamber (1). The lower end of each optical axis (3) is connected to the base (2), and the upper end is connected to the suspension rope drive control mechanism (8), so that the drive end of the suspension rope drive control mechanism (8) is located between the two optical axes (3) and is opposite to the central axis of the calibration oil chamber (1).

8. The underwater free-field pressure sensor impact calibration device according to claim 7, characterized in that: The drop hammer (5) has symmetrical lugs on both sides; the two lugs are respectively mounted on the outside of the two optical axes (3) through a linear bearing (4); The base (2) is provided with a positioning groove; the bottom of the cavity body (11) is provided with a positioning protrusion; the positioning groove and the positioning protrusion engage to achieve positioning; The lower end of the suspension rope (7) is connected to the center of the top of the drop hammer (5) through the suspension rope nut (6); The linear bearing (4) is interference-fitted with the lug.

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