Underwater chemical agent injection device redundancy control calculation method

Abstract

The application discloses a kind of underwater chemical agent injection equipment redundancy control calculation method, it is first obtained under different valve opening degree flow, differential pressure data, to fit out flow-differential pressure relationship, obtain flow coefficient parameter;Flow coefficient and opening degree relationship are fitted again, and the relationship formula of flow and opening degree, differential pressure is obtained;Finally, real-time flow can be obtained by the real-time opening degree and differential pressure obtained.Illustrative effect of the application is, by early calibration, the relationship formula between flow and valve opening degree, differential pressure is established;In subsequent actual production process, by adjusting control valve opening degree, and the way of obtaining real-time differential pressure, real-time flow can be quickly and accurately obtained, to ensure that reagent injection measurement is stable and accurate.

Description

Technical Field

[0001] This invention relates to the field of petroleum engineering, specifically to a flow control method for a subsea chemical agent injection metering valve used in subsea wellhead equipment. Background Technology

[0002] To ensure the normal operation of underwater oil pipelines and improve their service life and production efficiency, various chemicals need to be periodically introduced into the pipelines through underwater injection equipment. Regarding underwater injection equipment, the applicant previously filed a Chinese patent application (application number: 202110934610.9) which described the structure of an underwater chemical injection device, in which the orifice plate and flow channel groove can reduce the pressure of the high-pressure chemical flow.

[0003] Based on issues identified during subsequent practice, the applicant optimized and improved the structure of the underwater injection equipment, employing a single-stage fixed throttling system with a needle valve for flow control. However, as this is a non-standard device, traditional flow measurement formulas cannot be used, and the relevant flow parameters change with different needle valve openings, making fixed-parameter flow measurement impossible. Furthermore, the underwater chemical injection metering valve needs to be installed on the seabed, requiring a design life of at least 20 years, necessitating redundancy in the design to improve its reliability.

[0004] In order to quickly, accurately, and in real-time measure / control the flow rate of underwater chemical injection equipment, it is necessary to establish the relationship between flow rate and parameters such as valve opening, as well as multiple redundancy designs. Summary of the Invention

[0005] To solve the above technical problems, the main technical solution adopted by the present invention is as follows:

[0006] A redundancy control calculation method for an underwater chemical agent injection device includes a device body, wherein the device body comprises a chemical agent input connector, a pressure reducing component, a needle valve assembly, and a chemical agent output connector connected sequentially through a flow channel, characterized by the following steps:

[0007] Step 1: Control the opening degree V of the needle valve assembly to be fixed. Using the drug inlet connector as the inlet, inject drugs with different calibration flow rates Q into the device body for calibration. During this process, simultaneously acquire the front section differential pressure DP1 before and after the drug flows through the pressure reducing component, the rear section differential pressure DP2 before and after the drug flows through the needle valve assembly, and the overall differential pressure DP3 before and after the drug flows through both the pressure reducing component and the needle valve assembly.

[0008] The calibration array consists of the calibrated flow rate Q, the front differential pressure DP1, the rear differential pressure DP2, and the overall differential pressure DP3 under the same opening V.

[0009] Step 2: Fit the flow rate-differential pressure relationship under the same opening degree V using formula ①;

[0010]

[0011] in:

[0012] K is the flow coefficient;

[0013] DPn can be DP1, DP2, or DP3;

[0014] C is the calibration coefficient;

[0015] Step 3: Adjust the needle valve assembly to different opening degrees V, and repeat Step 1 and Step 2 to obtain the flow-differential pressure relationship under different opening degrees V;

[0016] This yields several fitting arrays corresponding to "opening degree V - rated flow rate Q - flow coefficient K - rated coefficient C";

[0017] Step 4: Fit the relationship between the flow coefficient K and the opening V using formula ②;

[0018] K = f(V), Formula ②;

[0019] Step 5: Substitute formula ② into formula ① to obtain the formulas for flow rate, opening degree, and differential pressure, as shown in formula ③:

[0020]

[0021] The mean of several calibration coefficients C;

[0022] Step 6: Connect the equipment body to the production system and introduce the reagent, setting the target flow rate Q. m The real-time opening V` of the needle valve assembly is adjusted from small to large. During this process, the real-time front differential pressure DP1` before and after the drug flows through the pressure reducing element, the real-time rear differential pressure DP2` before and after the drug flows through the needle valve assembly, and the real-time overall differential pressure DP3` before and after the drug flows through both the pressure reducing element and the needle valve assembly are obtained.

[0023] Calculate the real-time flow Q` using the following formula ④ until the real-time flow Q` equals the target flow Q. m ;

[0024]

[0025] Wherein: DPn` can be DP1`, DP2`, or DP3`.

[0026] By adopting the above scheme, the relationship between flow rate, valve opening, and differential pressure can be directly established through calibration. This allows for rapid and accurate acquisition of real-time flow rate in subsequent practical applications, ensuring stable and accurate drug injection metering.

[0027] A preferred technical solution is: in step two, a segmented metering flow value Q is set. f ;

[0028] When Q m >Q f If DPn in step two is either DP1 or DP1, then DPn` in step six is ​​either DP1`; if DPn in step two is either DP3 or DP3, then DPn` in step six is ​​either DP3`.

[0029] When Q m ≤Q f If DPn takes DP2 in step two, then DPn` takes DP2` in step six.

[0030] The above segmented measurement steps can yield more accurate calculation results.

[0031] A preferred technical solution is: in step two, the segmented flow rate value Q is used. f Based on the standard, the calibration array is partitioned according to the calibrated flow rate Q, and the flow rate-differential pressure relationship under the same opening V is fitted piecewise using formula ①;

[0032]

[0033] in:

[0034] When Q > Q f When DPn takes the form of DP1 or DP3;

[0035] When Q≤Q f When DPn takes the value DP2;

[0036] Q min <Q f <Q max ;

[0037] Q min The minimum calibrated flow rate Q injected into the device body;

[0038] Q max The maximum calibrated flow rate Q injected into the device body;

[0039] In step three, the needle valve assembly (5) is adjusted to different opening degrees V, and steps one and two are repeated, while maintaining the segmented metering flow rate value Q. f By keeping the opening V constant, we obtain the segmented relationship between flow rate and differential pressure under different opening degrees V;

[0040] In step four, the segmented flow rate value Q is used. fUsing the standard, the fitting array is partitioned according to the magnitude of the calibrated flow rate Q, and the relationship between the flow coefficient K and the opening V is fitted piecewise using formula ②;

[0041] In step five, formula ② is substituted into formula ① to obtain the segmented formulas for flow rate, opening degree, and differential pressure.

[0042] The above steps of segmented fitting and segmented measurement can simplify the initial fitting process, reduce the amount of calibration and data processing, and obtain more accurate calculation results.

[0043] A further preferred embodiment is: in step four;

[0044] K=f(V)=A*V+D, formula ②;

[0045] Where A and D are both parameters for fitting the opening degree.

[0046] The above linear fitting formula can accurately represent the relationship between K and V.

[0047] As a differential pressure measurement scheme, the device body also includes a first pressure sensor, a second pressure sensor, and a third pressure sensor;

[0048] The first pressure sensor is connected to the flow channel at the upstream end of the pressure reducing component to measure the upstream fluid pressure P1 before the drug flows through the pressure reducing component;

[0049] The second pressure sensor is connected to the flow channel between the pressure reducing element and the needle valve assembly to measure the mid-section fluid pressure P2 after the drug flows through the pressure reducing element and before the needle valve assembly;

[0050] The third pressure sensor is connected to the flow channel of the downstream section of the needle valve assembly to measure the downstream fluid pressure P3 after the drug flows through the needle valve assembly.

[0051] DP1 = P1 - P2;

[0052] DP2 = P2 - P3;

[0053] DP3 = ​​P1 - P3.

[0054] To accurately detect valve opening, the preferred solution is:

[0055] The device body also includes a linear displacement sensor and a rotational displacement sensor;

[0056] Both the sensing end of the linear displacement sensor and the sensing end of the rotational displacement sensor are connected to the opening and closing mechanism of the needle valve assembly.

[0057] Linear displacement sensors and rotational displacement sensors can be used in one step, but since the equipment is used underwater, setting up both linear displacement sensors and rotational displacement sensors at the same time can improve redundancy. Attached Figure Description

[0058] Figure 1 A schematic diagram of an underwater chemical injection device;

[0059] Figure 2 This is a structural schematic diagram of the wellhead connector 100;

[0060] Figure 3 This is a planar connection diagram of the wellhead connector 100, power unit 200, power transfer unit 300, drive unit 400, and fluid regulation unit 500.

[0061] Figure 4 for Figure 3 The left view;

[0062] Figure 5 for Figure 4 AA' section view;

[0063] Figure 6 for Figure 4 BB' sectional view;

[0064] Figure 7 for Figure 4 CC' section view;

[0065] Figure 8 This is a three-dimensional structural diagram of the threaded sleeve 53;

[0066] Figure 9 This is a schematic cross-sectional view of the pressure reducing seat 22;

[0067] Figure 10 This is a schematic diagram of the cross-sectional structure of valve seat 51;

[0068] Figure 11 A cross-sectional structural diagram of the electronic compartment 600 and the ROV connection 700;

[0069] Figure 12 Fitting curves for flow rate Q-sqrt(DP2) under different opening degrees;

[0070] Figure 13 The curve is the fitting curve of flow coefficient K1 and opening V;

[0071] Figure 14 The distribution of the percentage error of the flow rate calculated using DP1' versus the actual flow rate is shown in the figure.

[0072] Figure 15 The distribution of the percentage error of the flow rate calculated using DP2' versus the actual flow rate is shown in the figure.

[0073] Figure 16 This is a graph showing the percentage error of the flow rate calculated using DP3' and the distribution of the actual flow rate. Detailed Implementation

[0074] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0075] Example 1:

[0076] This embodiment employs full-segment fitting, and presents a redundancy control calculation method for an underwater chemical agent injection device. The device body includes a drug input connector 1, a pressure reducing component 2, a needle valve assembly 5, and a drug output connector 3, which are sequentially connected via flow channels. The method is implemented according to the following steps:

[0077] Step 1: Control and maintain the opening V of the needle valve assembly 5 at a fixed position. Using the drug inlet connector 1 as the inlet, inject drugs with different calibration flow rates Q into the device body for calibration. During this process, simultaneously acquire the front differential pressure DP1 before and after the drug flows through the pressure reducing component 2, the rear differential pressure DP2 before and after the drug flows through the needle valve assembly 5, and the overall differential pressure DP3 before and after the drug flows through both the pressure reducing component 2 and the needle valve assembly 5.

[0078] The calibration array consists of the calibrated flow rate Q, the front differential pressure DP1, the rear differential pressure DP2, and the overall differential pressure DP3 under the same opening V.

[0079] Step 2: Fit the flow rate-differential pressure relationship under the same opening degree V using formula ①;

[0080]

[0081] in:

[0082] K is the flow coefficient;

[0083] DPn can be DP1, DP2, or DP3;

[0084] C is the calibration coefficient;

[0085] Substituting the calibration array into formula ① will yield the K and C values;

[0086] Step 3: Adjust the needle valve assembly 5 to different opening degrees V, and repeat Step 1 and Step 2 to obtain the flow-differential pressure relationship under different opening degrees V;

[0087] This yields several fitting arrays corresponding to "opening degree V - rated flow rate Q - flow coefficient K - calibration coefficient C"; each fitting array includes an opening degree V value, several rated flow rate Q values, a flow coefficient K value, and a calibration coefficient C value.

[0088] Step 4: Then, use formula ② to fit the relationship between the flow coefficient K and the opening V;

[0089] K = f(V), Formula ②;

[0090] A specific fitting formula for formula ② could be K = f(V) = A*V + D, formula ②;

[0091] Where: A and D are both aperture fitting parameters;

[0092] Substituting the K and V values ​​of several fitted arrays into formula ② will yield the A and D values;

[0093] Step 5: Substitute formula ② into formula ① to obtain the formulas for flow rate, opening degree, and differential pressure, as shown in formula ③:

[0094]

[0095] The mean of several calibration coefficients C;

[0096] This yields the relationship between flow rate Q, opening degree V, and differential pressure DP.

[0097] Step 6: Connect the equipment body to the production system and introduce the reagent, setting the target flow rate Q. m The real-time opening V` of the needle valve assembly 5 is adjusted from small to large. During this process, the real-time front differential pressure DP1` before and after the drug flows through the pressure reducing component 2, the real-time rear differential pressure DP2` before and after the drug flows through the needle valve assembly 5, and the real-time overall differential pressure DP3` before and after the drug flows through both the pressure reducing component 2 and the needle valve assembly 5 are obtained.

[0098] Calculate the real-time flow Q` using the following formula ④ until the real-time flow Q` equals the target flow Q. m ;

[0099]

[0100] Wherein: DPn` can be DP1`, DP2`, or DP3`.

[0101] In order to measure differential pressure values ​​such as DP1, DP2 and DP3, the device body also includes a first pressure sensor (61), a second pressure sensor (62) and a third pressure sensor;

[0102] The first pressure sensor 61 is connected to the flow channel at the upstream end of the pressure reducing component 2 to measure the upstream fluid pressure P1 before the drug flows through the pressure reducing component 2;

[0103] The second pressure sensor 62 is connected to the flow channel between the pressure reducing component 2 and the needle valve assembly 5 to measure the mid-section fluid pressure P2 after the drug flows through the pressure reducing component 2 and before the needle valve assembly 5;

[0104] The third pressure sensor is connected to the flow channel of the downstream section of the needle valve assembly 5 to measure the downstream fluid pressure P3 after the drug flows through the needle valve assembly 5.

[0105] DP1 = P1 - P1;

[0106] DP2 = P2 - P3;

[0107] DP3 = ​​P1 - P3.

[0108] The opening degree of the needle valve assembly 5 is related to the position of the valve needle. In order to detect the position of the valve needle, the device body also includes a linear displacement sensor and a rotational displacement sensor. The sensing end of the linear displacement sensor and the sensing end of the rotational displacement sensor are respectively connected to the opening and closing part (e.g., valve stem) of the needle valve assembly 5. The linear displacement sensor and the rotational displacement sensor are redundant to each other. When a certain position sensing method fails / becomes inaccurate, there is still an effective and reliable replacement solution. The calculation method of the opening degree is the prior art and will not be described in detail here.

[0109] Example 2:

[0110] This embodiment uses segmented control and real-time flow measurement, and its only difference from Embodiment 1 is:

[0111] In step two, the segmented metering flow rate value Q is set. f According to the segmented metered flow rate value Q f Compared with the target flow Q in step six m The size is controlled in segments, specifically:

[0112] When Q m >Q f In step two, DPn can be either DP1 or DP2 for fitting. However, if DPn in step two is DP1, then DPn` in step six should be DP1`; if DPn in step two is DP3, then DPn` in step six should be DP3`.

[0113] When Q m ≤Q f If DPn takes DP2 in step two, then DPn` in step six should take DP2`.

[0114] Example 3:

[0115] This embodiment uses a piecewise fitting and piecewise control method to measure real-time flow, which differs from Embodiment 1 in that:

[0116] In step two, the segmented metering flow rate value Q is set. f The segmented flow rate value Q f Based on the division criteria, the calibration array is partitioned according to the magnitude of the calibrated flow rate Q, that is, the calibration array is divided into a large flow rate calibration array and a small flow rate calibration array, and then the flow rate-differential pressure relationship of the large flow rate calibration array and the small flow rate calibration array under the same opening V is fitted piecewise;

[0117] The flow-differential pressure relationship fitting formulas for both the large-flow calibration array and the small-flow calibration array are expressed as formula ①:

[0118]

[0119] in:

[0120] When Q > Q f When DPn takes the form of DP1 or DP3;

[0121] When Q≤Q f When DPn takes the value DP2;

[0122] Q min <Q f <Q max ;

[0123] Q min The minimum calibrated flow rate Q injected into the device body;

[0124] Q max The maximum calibrated flow rate Q injected into the device body;

[0125] At this point, another way to express formula ① is:

[0126] DPm can be either DP1 or DP3; K1 is the high flow rate coefficient; C1 is the high flow rate calibration coefficient; K2 is the low flow rate coefficient; C2 is the low flow rate calibration coefficient;

[0127] In step three, the needle valve assembly (5) is adjusted to different opening degrees V, and steps one and two are repeated, while maintaining the segmented metering flow rate value Q. f By keeping the opening V constant, we obtain the segmented relationship between flow rate and differential pressure under different opening degrees V;

[0128] In step four, the segmented flow rate value Q continues to be used. f To determine the partitioning criteria, the fitted array is divided according to the magnitude of the calibrated flow rate Q, i.e., Q > Q0. fThe fitted array is divided into a high-flow-rate fitted array, and Q≤Q f The fitted array is divided into a small flow fitted array;

[0129] Then, the relationship between the flow coefficient K and the opening V is fitted piecewise using formula ②;

[0130] Another way to express Formula ② is:

[0131]

[0132] A1 and D1 are fitting parameters for high flow rate opening;

[0133] A2 and D2 are fitting parameters for low flow rate opening;

[0134] In step five, substituting formula ② into formula ① yields the segmented formulas for flow rate, opening degree, and differential pressure, as shown in formula ③. Another way to express formula ③ at this point is:

[0135]

[0136] The average value of several large flow rate calibration coefficients C1;

[0137] The average of several small flow rate calibration coefficients C2;

[0138] In step six, the real-time flow rate Q` is calculated according to the following formula ④;

[0139]

[0140] When Q m >Q f When DPn` is DP1` or DP3`; for

[0141] When Q m ≤Q f When DPn` is DP2; for

[0142] At this point, DP1` and DP1, DP2` and DP2, and DP3` and DP3 still have a mathematical correspondence.

[0143] Example 4:

[0144] like Figure 1-11As shown, an underwater chemical agent injection device includes a device body, which includes a treehouse connector 100, a power unit 200, a power transfer unit 300, a drive unit 400, a fluid regulation unit 500, an electronic compartment 600, and an ROV connection unit 700 connected in sequence.

[0145] The wellhead connector 100 includes a docking cylinder 101. The upstream end of the docking cylinder 101 is used to connect to the corresponding interface on the wellhead, and the downstream end of the docking cylinder 101 is connected to the power unit 200. The cylinder wall of the docking cylinder 101 has several water-permeable holes. At least three connecting lugs 102 are provided on the inner wall of the docking cylinder 101. The connecting lugs 102 are close to the power unit 200 and are fixed to it by bolts.

[0146] The power unit 200 includes a power unit housing 201, which is cylindrical. The power unit housing 201 and the docking cylinder 101 are arranged along the same center line. The interior of the power unit housing 201 is used to install internal components. The upstream end of the power unit housing 201 is connected to the end of the docking cylinder 101 through the connecting lug 102. The downstream end of the power unit housing 201 is connected to the power adapter 300.

[0147] The power adapter 300 includes a power adapter housing 301, which is cylindrical and is arranged along the same center line as the power unit housing 201. The interior of the power adapter housing 301 is used to install internal components.

[0148] The downstream end face of the power unit housing 201 is provided with a first embedding recess, and the upstream end face of the power adapter housing 301 is provided with a first embedding boss. The first embedding boss matches the first embedding recess and extends into the first embedding recess. The downstream end face of the power unit housing 201 and the upstream end face of the power adapter housing 301 are fitted together to form a stepped first sealing surface. A first axial sealing ring and a first radial sealing ring are provided at the first sealing surface. The first radial sealing ring is located on the mating surface of the first embedding boss and the first embedding recess and is used to seal the radial mating portion of the mating surface of the first embedding boss and the first embedding recess. The first axial sealing ring is located outside the first radial sealing ring and is used to axially seal the downstream end face of the power unit housing 201 and the upstream end face of the power adapter housing 301 outside the first radial sealing ring. The downstream end face of the power adapter housing 301 is connected to the drive unit 400.

[0149] The drive unit 400 includes a drive unit housing 401, which is cylindrical. The drive unit housing 401 and the power adapter housing 301 are arranged along the same center line. The interior of the drive unit housing 401 is used to install internal components.

[0150] The upstream end face of the drive housing 401 is provided with a second embedding recess, and the downstream end face of the power adapter housing 301 is provided with a second embedding boss. The second embedding boss matches the second embedding recess and extends into the second embedding recess. The downstream end face of the power adapter housing 301 and the upstream end face of the drive housing 401 are fitted together to form a stepped second sealing surface. A second axial sealing ring and a second radial sealing ring are provided at the second sealing surface. The second radial sealing ring is located on the mating surface of the second embedding boss and the second embedding recess and is used to seal the radially mating portion of the mating surface of the second embedding boss and the second embedding recess. The second axial sealing ring is located outside the second radial sealing ring and is used to axially seal the downstream end face of the power adapter housing 301 outside the second radial sealing ring and the upstream end face of the drive housing 401. The downstream end face of the drive housing 401 is connected to the fluid regulating part 500.

[0151] The downstream end of the power unit housing 201, the upstream end of the drive unit housing 401, and the power adapter housing 301 are tightened by a plurality of first axial tension bolts. All the first axial tension bolts are arranged around the center line of the power adapter housing 301. The first axial tension bolts pass through the downstream end of the power unit housing 201, the upstream end of the drive unit housing 401, and the power adapter housing 301.

[0152] The fluid regulating unit 500 includes a regulating unit housing 501, which is cylindrical. The regulating unit housing 501 and the drive unit housing 401 are arranged along the same center line. The interior of the regulating unit housing 501 is used to install internal components.

[0153] The upstream end face of the adjusting housing 501 is provided with a third embedding boss, and the downstream end face of the driving housing 401 is provided with a third embedding recess. The third embedding boss matches the third embedding recess and extends into the third embedding recess. The downstream end face of the driving housing 401 and the upstream end face of the adjusting housing 501 are fitted together to form a stepped third sealing surface. A third axial sealing ring and a third radial sealing ring are provided on the third sealing surface. The third radial sealing ring is located on the mating surface of the third embedding boss and the third embedding recess and is used to seal the radial mating portion of the mating surface of the third embedding boss and the third embedding recess. The third axial sealing ring is located outside the third radial sealing ring and is used to axially seal the downstream end face of the driving housing 401 outside the third radial sealing ring and the upstream end face of the adjusting housing 501. The downstream end face of the adjusting housing 501 is connected to the electronic compartment 600.

[0154] The downstream end of the drive housing 401 and the upstream end of the adjustment housing 501 are tightened by a plurality of second axial tension bolts. All the second axial tension bolts are arranged around the center line of the drive housing 401 and / or the adjustment housing 501, and the second axial tension bolts pass through the downstream end of the drive housing 401 and the upstream end of the adjustment housing 501 at the same time.

[0155] A fourth embedding recess is provided on the downstream end face of the adjusting part housing 501, and a sealing partition 502 is embedded in the fourth embedding recess. The sealing partition 502 matches the fourth embedding recess. The downstream end face of the adjusting part housing 501 and the sealing partition 502 are tightened by several bolts. Several fourth radial sealing rings are provided between the radial contact surfaces of the adjusting part housing 501 and the sealing partition 502.

[0156] The power unit housing 201, power transfer housing 301, drive unit housing 401, and adjustment unit housing 501 are connected to form the equipment housing. The purpose of the separate equipment housing is to facilitate the subsequent installation and sealing of internal components. The internal spaces of the power unit housing 201, power transfer housing 301, drive unit housing 401, and adjustment unit housing 501 are axially connected and can form an internal component installation area. Internal components are provided in the internal component installation area, including a pressure reducing component 2 and a needle valve assembly 5.

[0157] A chemical input connector 1, a chemical output connector 3, and a tree plug x are installed on the upstream end face of the power unit housing 201. The chemical input connector 1, the chemical output connector 3, and the tree plug x are all commercially available products. All three are axially located on the upstream end face of the power unit housing 201, and their center lines are parallel to each other. Their product structure and installation structure will not be described in detail here.

[0158] The "upstream end" and "downstream end" mentioned in the above description are based on the connection sequence of the wellhead connector 100, power unit 200, power transfer unit 300, drive unit 400, fluid regulation unit 500, electronic compartment 600, and ROV connection unit 700 in the equipment. The wellhead connector 100 is defined as upstream, and the ROV connection unit 700 is defined as downstream.

[0159] A flow channel is provided in the solid part of the device housing (i.e., the part between the inner wall and the outer wall of the device housing), the inlet end of the flow channel is connected to the drug input connector 1, and the outlet end of the flow channel is connected to the drug output connector 3.

[0160] The drug inlet connector 1, the pressure reducing component 2, the needle valve assembly 5, and the drug outlet connector 3 are connected in sequence through the flow channel;

[0161] Specifically: The pressure-reducing component 2 includes a pressure-reducing sleeve 21 and a pressure-reducing seat 22. The pressure-reducing sleeve 21 is cylindrical. The pressure-reducing sleeve 21 can be an independent shell disposed within the adjusting part housing 501, or it can be integrally formed with the adjusting part housing 501, or it can be equal to the adjusting part housing 501. Taking the case where the pressure-reducing sleeve 21 is equal to the adjusting part housing 501 as an example:

[0162] The inner cavity of the adjusting housing 501 (pressure reducing sleeve 21) is cylindrical, and the pressure reducing seat 22 is cylindrical. The pressure reducing seat 22 is axially embedded inside the pressure reducing sleeve 21, and the pressure reducing seat 22 is located in the downstream section of the adjusting housing 501.

[0163] At least three pressure-reducing channels 22a are provided in the solid area inside the pressure-reducing seat 22. The total number of pressure-reducing channels 22a is odd. The pressure-reducing channels 22a are threaded, and each pressure-reducing channel 22a has a different spiral diameter. The multiple pressure-reducing channels 22a are arranged along a common center line. The spiral diameter of the multiple pressure-reducing channels 22a increases radially from the inside to the outside. Each pressure-reducing channel 22a is a channel with a circular cross-section and has the same channel diameter. One end of each pressure-reducing channel 22a is a pressure-reducing channel inlet, and the other end is a pressure-reducing channel outlet. The pressure-reducing channel inlet of the outer layer and the pressure-reducing channel outlet of the adjacent inner layer are located at the same end of the pressure-reducing seat 22. The pressure-reducing channel outlet of the outer layer and the pressure-reducing channel inlet of the adjacent inner layer are located at the same end of the pressure-reducing seat 22. Two adjacent pressure-reducing channels 22a in the inner and outer layers are connected end to end in sequence.

[0164] The pressure-reducing seat 22 is provided with a pressure-reducing inlet and a pressure-reducing outlet. The pressure-reducing inlet communicates with the inlet of the outermost first pressure-reducing channel 22a, and the pressure-reducing outlet communicates with the outlet of the innermost last pressure-reducing channel 22a. In a more specific embodiment, the pressure-reducing inlet opens onto the cylindrical outer wall of the pressure-reducing seat 22, away from the downstream end of the adjusting housing 501 (and also away from the sealing partition 502). The pressure-reducing outlet opens onto one end face of the pressure-reducing seat 22, facing the downstream end of the adjusting housing 501 (and also towards the sealing partition 502). The pressure-reducing inlet and outlet are respectively close to both ends of the pressure-reducing seat 22. The inner wall of 1 is provided with an annular drug inlet cavity around the pressure reducing component inlet. The annular drug inlet cavity is connected to the pressure reducing component inlet. The flow channel is connected to the annular drug inlet cavity. A low-pressure drug center flow channel is provided on the pressure reducing seat 22 along its center line. A low-pressure drug outflow space is reserved between the pressure reducing seat 22 and the closed partition 502. The pressure reducing component inlet is connected to the low-pressure drug outflow space. The low-pressure drug outflow space is connected to the inlet of the low-pressure drug center flow channel. The outlet of the low-pressure drug center flow channel extends to the needle valve assembly 5.

[0165] A specific embodiment of a needle valve assembly 5 is as follows: the needle valve assembly 5 includes a valve seat 51, a valve needle 52, a screw sleeve 53, a sliding sleeve sleeve 54, a drive motor 57, and a drive screw 58;

[0166] The valve seat 51 is located in the upstream section of the regulating housing 501. The valve seat 51 is abutted against and axially pressed against the pressure reducing seat 22. The valve seat 51 includes a throttling seat 511 and a needle sleeve 512.

[0167] A throttling seat recess is provided on the end face of the pressure reducing seat 22 facing the needle valve assembly 5. The throttling seat 511 matches the throttling seat recess and is embedded in the throttling seat recess. A throttling seat cover plate recess is provided on the end face of the throttling seat 511 facing away from the pressure reducing seat 22. A throttling seat cover plate 513 is embedded in the throttling seat cover plate recess. The throttling seat cover plate 513 is connected and tightened to the throttling seat 511 by several bolts. A throttling seat ring mounting through hole is provided at the center of the throttling seat cover plate 513. The throttling seat ring mounting through hole is a circular hole. A throttling seat ring 514 is embedded in the throttling seat ring mounting through hole. The throttling seat ring 514 includes a throttling abutment and a throttling extension. The throttling abutment is disc-shaped and located at the throttling seat ring mounting through hole. The throttling extension is cylindrical and coaxially arranged with the throttling abutment. The outer diameter of the throttling extension is smaller than that of the throttling abutment. The end faces of the throttling extension and the throttling abutment opposite to the throttling seat 511 are fixedly connected. The free end face of the throttling extension is flush with the end face of the throttling seat cover plate 513. The throttling abutment and the throttling extension are integrally formed. An abutment retaining ring extends integrally into the inner wall of the throttling seat ring mounting through hole. The abutment retaining ring is away from the throttling seat 511. During the tightening process of the throttling seat cover plate 513 and the throttling seat 511 by several bolts, the abutment retaining ring squeezes the throttling abutment to make it axially press against the end face of the throttling seat 511.

[0168] A throttling orifice 51c extends through the centerline of the throttling seat 511 and the throttling seat ring 514. The inlet of the throttling orifice 51c forms a needle valve inlet, which is connected to and communicates with the outlet end of the low-pressure agent central flow channel.

[0169] The needle sleeve 512 is cylindrical and coaxially fitted into the inner cavity of the adjusting part housing 501. Along its centerline, the needle sleeve 512 is sequentially provided with a transition hole 51b, a valve stem sliding hole, and a valve needle sealing hole 51a. All three holes are circular. The inner diameter of the transition hole 51b is larger than the diameter of the valve needle 52. The inner diameter of the valve needle sliding hole is larger than the diameter of the valve needle 52 but smaller than the inner diameter of the transition hole 51b. The inner diameter of the valve needle sealing hole 51a is larger than the diameter of the valve needle 52. The valve needle sealing hole 51a and the valve needle sealing hole 51a are axially connected in sequence and their center lines coincide. The valve needle sealing hole 51a faces away from the throttle seat 511, and the transition hole 51b faces the throttle seat 511. The transition hole 51b is connected to and connected to the outlet end of the throttle hole 51c. At least two radial drug outlet holes 51d are also provided on the throttle seat 511. The center line of the radial drug outlet hole 51d is perpendicular to the center line of the transition hole 51b. All the radial drug outlet holes 51d are evenly distributed around the transition hole 51b. The inner end of the radial drug outlet hole 51d is connected to the transition hole 51b. The outer end of the radial drug outlet 51d forms the needle valve outlet; an annular drug outlet cavity is provided around the center line of the outer wall of the throttling seat 511, the needle valve outlet communicates with the annular drug outlet cavity, the flow channel communicates with the annular drug outlet cavity, a valve needle sealing sleeve 55 is embedded in the valve needle sealing hole 51a, the valve needle sealing sleeve 55 includes a first valve needle sealing element 551 and a second valve needle sealing element 552, the valve needle sealing hole 51a is a two-stage stepped hole, the small hole section of the valve needle sealing hole 51a communicates with the valve needle sliding hole, and the first valve needle sealing element 551 is located in the valve needle sealing hole 51a. The bottom of the small hole section of valve needle seal 551 is provided with a sealing structure between the small hole section wall of valve needle sealing hole 51a and the second valve needle seal 552 is threadedly assembled with the large hole section of valve needle sealing hole 51a. The second valve needle seal 552 extends a pushing part towards the first valve needle seal 551. The pushing part extends into the small hole section of valve needle sealing hole 51a. The pushing part axially abuts against and presses the first valve needle seal 551. A sealing structure is provided between the pushing part and the small hole section wall of valve needle sealing hole 51a.

[0170] A valve needle through hole is provided at the center line of the first-stage valve needle seal 551 and the second-stage valve needle seal 552. The valve needle 52 is movably inserted into the valve needle through hole. A sliding sealing structure is provided between the outer wall of the valve needle 52 and the inner wall of the valve needle through hole. The center line of the valve needle 52 coincides with the center line of the valve needle through hole (or the valve needle sealing hole 51a). The head of the valve needle 52 extends into the transition hole 51b and is aligned with the throttling hole 51c.

[0171] The valve needle 52 includes a valve stem and a needle tip. The head of the valve stem is connected to the needle tip, the needle tip is aligned with the throttling orifice 51c, the outer wall of the needle tip matches the orifice wall of the throttling orifice 51c, and the tail of the valve stem extends into the drive housing 401.

[0172] A valve seat retaining ring 402 is sandwiched between the drive housing 401 and the adjustment housing 501. The valve seat retaining ring 402 is axially pressed against the needle sleeve 512 and a section of the valve needle seal 551. With the cooperation of the valve seat retaining ring 402, the needle sleeve 512 and the section of the valve needle seal 551, the internal spaces of the drive housing 401 and the adjustment housing 501 are relatively isolated.

[0173] In the above structure, the head of the valve needle 52 extends into the valve seat 51, and the head of the valve needle 52 is located between the needle valve inlet and the needle valve outlet to adjust the opening degree of the needle valve.

[0174] The drive motor 57 is located inside the power unit housing 201. The output shaft of the drive motor 57 faces the power transfer unit 300. The housing of the drive motor 57 is fixed to the downstream end face of the power unit housing 201 by bolts. The output shaft of the drive motor 57 extends into the power transfer housing 301 and is axially connected to the rotating seal. A drive rotor 59 is assembled inside the power transfer housing 301. The drive rotor 59 is rotatably assembled with the inner wall of the power transfer housing 301. The rotation center line of the drive rotor 59 coincides with the center line of the power transfer housing 301. A rotating seal (rotary seal) is provided between the drive rotor 59 and the inner wall of the power transfer housing 301. The drive rotor 59 and the rotating seal cooperate to seal the internal space of the power transfer housing 301, thereby isolating the internal space of the power unit housing 201 and the internal space of the drive unit housing 401 from each other.

[0175] The drive screw 58 and the screw sleeve 53 are both located inside the drive housing 401. The drive screw 58 and the screw sleeve 53 are coaxially threaded together. The center line of the drive screw 58 coincides with the center line of the drive housing 401. One end of the drive screw 58 is coaxially fixedly connected to the drive rotating seat 59.

[0176] The threaded sleeve 53 is slidably assembled inside the sliding sleeve sleeve 54. The sliding sleeve sleeve 54 can be an independent shell provided in the drive unit outer shell 401, or it can be a part of the drive unit outer shell 401, or it can be equal to the drive unit outer shell 401.

[0177] Taking the sliding sleeve 54 as an example, which is equivalent to the drive unit housing 401: the threaded sleeve 53 is cylindrical and is assembled in the internal space of the drive unit housing 401. To reduce the friction between the threaded sleeve 53 and the drive unit housing 401, the threaded sleeve 53 is clearance-fitted with the drive unit housing 401. To ensure the smooth sliding of the threaded sleeve 53 inside the drive unit housing 401, two annular limiting grooves 53a are provided on the outer wall of the threaded sleeve 53 around its center line. The two annular limiting grooves 53a are distributed along the axial direction of the threaded sleeve 53. Guide sliding rings 531 are respectively fitted in the two annular limiting grooves 53a, and the guide sliding rings 531 are slidably assembled with the inner wall of the sliding sleeve 54.

[0178] The guide sliding ring 531 can be made of plastic (e.g., PEEK) to reduce friction with the inner wall of the drive housing 401. To further reduce friction, a lubricant can be added. The two openings of the drive housing 401 are respectively sealed by the "drive rotary seat 59 / rotation seal" and the "valve seat retaining ring 402 / needle sleeve 512 / segment valve needle seal 551" to form a relatively sealed space, and the sliding lubricant is filled between the threaded sleeve 53 and the drive housing 401.

[0179] The axial length of the drive housing 401 is greater than the axial length of the threaded sleeve 53. Since the drive housing 401 is relatively sealed, the spaces at both ends of the threaded sleeve 53 need to be connected to ensure its normal sliding. The way the spaces at both ends of the threaded sleeve 53 are connected can be:

[0180] On the outer wall of the threaded sleeve 53, corresponding to each of the annular limiting grooves 53a, there is a strip-shaped pressure balancing groove 53b. The length direction of the pressure balancing groove 53b is perpendicular to the width direction of the annular limiting groove 53a, and the depth of the pressure balancing groove 53b is greater than the depth of the annular limiting groove 53a. The pressure balancing grooves 53b extend into the two side walls of the annular limiting groove 53a, connecting the spaces on both sides of the guide sliding ring 531. Since the threaded sleeve 53 and the drive housing 401 are in clearance fit, the spaces at both ends of the threaded sleeve 53 are connected through the pressure balancing groove 53b and the gap between the threaded sleeve 53 and the drive housing 401. This connection method also has the effect that during each sliding process of the threaded sleeve 53, lubricant is pushed through the gap between the threaded sleeve 53 and the drive housing 401, so as to fully lubricate both of them.

[0181] The threaded sleeve 53 has a drive threaded through hole at its center line. The drive screw 58 is threadedly connected to the drive threaded through hole. The solid part of the threaded sleeve 53 has at least one (or two) lubricant balance holes 53c. The lubricant balance holes 53c are arranged radially. The outer end of the lubricant balance hole 53c extends to the outer wall of the threaded sleeve 53. The inner end of the lubricant balance hole 53c communicates with the drive threaded through hole.

[0182] A lubricant injection blind hole 54a is provided on the outer wall of the drive unit housing 401. The bottom of the lubricant injection blind hole 54a has a lubricant through hole communicating with the inner cavity of the drive unit housing 401. A piston 541 is assembled in the lubricant injection blind hole 54a, and a piston limiting ring 542 is fixed at the outer end of the lubricant injection blind hole 54a. The lubricant injection blind hole 54a is used to inject lubricant into the interior of the drive unit housing 401. Before being submerged, the piston 541 is located at the outer end of the lubricant injection blind hole 54a. During the lubricant injection process, air may easily remain inside the drive unit housing 401. Therefore, as much lubricant as possible should be filled inside the piston 541. After the equipment is placed underwater, the piston 541 is automatically moved to the bottom of the lubricant injection blind hole 54a under the action of water pressure, thereby forcing the lubricant in the lubricant injection blind hole 54a into the inner cavity of the drive unit housing 401 and maintaining the internal and external pressure balance.

[0183] The tail of the valve needle 52 is axially fixedly connected to the threaded sleeve 53 and circumferentially rotatably connected. The threaded sleeve 53 slides within the drive housing 401, thereby driving the valve needle 52 to move axially.

[0184] The solid portion of the threaded sleeve 53 is also axially provided with a threaded sleeve guide rod. The threaded sleeve guide rod is eccentrically arranged, and its two ends are respectively fixed to the downstream end face of the power adapter housing 301 and the upstream end face of the adjustment housing 501. The center line of the threaded sleeve guide rod is parallel to the center line of the threaded sleeve 53. The threaded sleeve guide rod is slidably assembled with the threaded sleeve 53. When the drive screw 58 rotates, the threaded sleeve 53 slides axially due to the restriction of the threaded sleeve guide rod.

[0185] The device body also includes a first pressure sensor 61, a second pressure sensor 62, and a third pressure sensor;

[0186] The first pressure sensor 61 is connected to the flow channel at the upstream end of the pressure reducing component 2 to measure the upstream fluid pressure P1 before the drug flows through the pressure reducing component 2;

[0187] The second pressure sensor 62 is connected to the flow channel between the pressure reducing component 2 and the needle valve assembly 5 to measure the mid-section fluid pressure P2 after the drug flows through the pressure reducing component 2 and before the needle valve assembly 5;

[0188] The third pressure sensor is connected to the flow channel of the downstream section of the needle valve assembly 5 to measure the downstream fluid pressure P3 after the drug flows through the needle valve assembly 5.

[0189] The closed partition 502 is provided with a first pressure detection hole, a second pressure detection hole and a third pressure detection hole. The first pressure sensor 61 is sealed in the first pressure detection hole, the second pressure sensor 62 is sealed in the second pressure detection hole and the third pressure sensor is sealed in the third pressure detection hole.

[0190] The sealing isolation ring 231, the sealing isolation orifice plate 232, and the sealing isolation cylinder 233 are integrally formed.

[0191] The electronic compartment 600 includes an electronic compartment housing 601, which is connected to the downstream end of the adjustment part housing 501 by a number of bolts. A PCB module 602 is suspended inside the electronic compartment housing 601. At least two blind holes for supporting columns are provided on the closed partition 502 facing the PCB module 602. The center line of the blind holes for supporting columns is parallel to the center line of the adjustment part housing 501. The box support column 603 is threaded into the blind holes for supporting columns and extends into the electronic compartment housing 601. The PCB module 602 is fixedly connected to the box support column 603 by bolts.

[0192] At least two electrical connectors are provided on the enclosed partition 502, and at least two wiring harness holes are provided on the solid part of the equipment housing. The control wiring harness of the drive motor 57 is connected to the corresponding electrical connector through the wiring harness hole, and the wiring harness of the oil well plug x is connected to the corresponding electrical connector through the wiring harness hole.

[0193] The electrical connectors and the output terminals of the first, second, and third pressure sensors 61, 62, and 63 are connected to the PCB module 602 via wiring harnesses.

[0194] The ROV connection 700 includes an ROV connection housing 701 and an ROV drive handle 704. The connection housing 701 is fixedly connected to the electronic compartment housing 601. An ROV stud 702 is fixedly installed inside the ROV connection housing 701. The center line of the ROV stud 702 is parallel to the center line of the chemical input connector 1 / chemical output connector 3 / tree power plug x. An ROV sleeve 703 is threaded onto the ROV stud 702. The ROV drive handle 704 is fixedly connected to the ROV sleeve 703. The ROV sleeve 703 is rotatably assembled with and sealed to the connection housing 701.

[0195] A first alignment mark groove is provided at the connection between the power unit housing 201 and the power transfer housing 301. A second alignment mark groove is provided at the connection between the power transfer housing 301 and the drive unit housing 401. A third alignment mark groove is provided at the connection between the drive unit housing 401 and the adjustment housing 501. The first, second, and third alignment mark grooves can be located on the same axial straight line. A guide block is also provided on the outer wall of the power unit housing 201. The guide block is used to guide the connection process between the equipment and the tree.

[0196] The valve needle 52 is used to control the opening degree of the needle valve assembly 5. The opening degree of the needle valve assembly 5 can be calculated based on the position of the valve needle 52. The sensing end of the linear displacement sensor is fixedly connected to the screw sleeve 53. The sensing end of the rotational displacement sensor is connected to the output shaft of the drive motor 57. The rotational displacement sensor can also be integrated with the drive motor 57 (servo motor).

[0197] The linear displacement sensor and the rotational displacement sensor are used to detect the position of the valve needle, thereby calculating the opening degree of the needle valve.

[0198] Example 5:

[0199] A redundancy control calculation method for an underwater chemical injection device, including the underwater chemical injection device of Example 4, is performed according to the following steps:

[0200] Step 1: Control and maintain the opening V of the needle valve assembly 5 at a fixed value. Using the drug inlet connector 1 as the inlet, inject drugs with different calibration flow rates Q into the device body for calibration. During this process, simultaneously acquire the front differential pressure DP1 before and after the drug flows through the pressure reducing component 2, the rear differential pressure DP2 before and after the drug flows through the needle valve assembly 5, and the overall differential pressure DP3 before and after the drug flows through both the pressure reducing component 2 and the needle valve assembly 5.

[0201] The calibration flow rate Q, the front differential pressure DP1, the rear differential pressure DP2, and the overall differential pressure DP3 under the same opening V correspond to each other to form a calibration array. In order to improve the fitting accuracy, the number of calibration arrays should not be too small. It is preferable to calibrate 10 times or more under the same opening V.

[0202] Adjust the needle valve assembly (5) to different opening degrees V, and repeat the above calibration process. A portion of the calibration array data is shown in Table 1.

[0203] Step 2: Fit the flow rate-differential pressure relationship under different opening degrees according to formula ① to obtain several flow coefficients K and calibration coefficients C under different opening degrees. These, together with the corresponding opening degree V and flow rate Q, form several fitting arrays.

[0204] Let DPn be DP1, DP2, or DP3 respectively; substituting them into the fitted flow formula in formula ①, we get:

[0205]

[0206] In the above formula:

[0207] Q1, Q2, and Q3 represent the flow rates fitted using DP1, DP2, and DP3, respectively.

[0208] K1, K2, and K3 are the flow coefficients fitted using DP1, DP2, and DP3, respectively.

[0209] C1, C2, and C3 are the calibration coefficients fitted using DP1, DP2, and DP3, respectively.

[0210] This yields several fitting arrays corresponding to "opening degree V - rated flow rate Q - flow coefficient K - rated coefficient C", and the results are shown in Table 1.

[0211] To more intuitively illustrate the linear relationship between flow rate Q and differential pressure DP, flow rate Q-sqrt(DP²) curves were plotted for different opening degrees V. The results are as follows: Figure 12 As shown. From Figure 12 It can be seen that there is a good linear relationship between the flow rate Q and the corresponding sqrt(DP2) under different opening degrees V. There are also good corresponding linear relationships between the flow rate Q and sqrt(DP1), and between the flow rate Q and sqrt(DP3), which will not be elaborated here.

[0212] Step 3: Fit the relationships between the flow coefficients K1, K2, K3 and the opening V, as shown in the following formula;

[0213]

[0214] In the above formula:

[0215] A1 and D1 are the aperture fitting parameters obtained by fitting using DP1, respectively;

[0216] A2 and D2 are the aperture fitting parameters obtained by fitting using DP2, respectively;

[0217] A3 and D3 are the aperture fitting parameters obtained by fitting using DP3, respectively;

[0218] Taking K1=f(V)=A1*V+D1 as an example, the fitted parameters A1 and D1 are shown in Table 1;

[0219] Table 1. Statistical Table of Calibration Array, Fitted Array, and Partial Opening Fitting Parameters

[0220]

[0221] The fitting method for K2=f(V)=A2*V+D1 and K3=f(V)=A3*V+D3 is the same as that for K1=f(V)=A1*V+D1. The fitting can obtain parameters A2, D2, A3, and D3; the fitting process and results will not be elaborated here.

[0222] To more intuitively illustrate the linear relationship between K1 and aperture V, a K1-V curve was plotted, and the result is as follows: Figure 13 As shown. From Figure 13 It can be seen that there is a good linear relationship between the flow coefficient K1 and the opening V. Similarly, the flow coefficients K2 and K3 also have good corresponding linear relationships with the opening V, which will not be elaborated here.

[0223] Step 4: Combine the above two equations to obtain the formulas for flow rate, opening degree, and differential pressure, as follows:

[0224]

[0225] Let C1 be the mean of several C1 values;

[0226] The mean of several C2 values;

[0227] The mean of several C3 values;

[0228] Step 5: For a more intuitive comparison, the front-end differential pressure DP1, rear-end differential pressure DP2, and overall differential pressure DP3 in Table 1 are equated to the real-time front-end differential pressure DP1', real-time rear-end differential pressure DP2', and real-time overall differential pressure DP3'. Substituting these values ​​into the corresponding formulas yields the corresponding real-time flow rates Q1', Q2', and Q3'. Q1' is the real-time flow rate calculated using DP1', Q2' is the real-time flow rate calculated using DP2', and Q3' is the real-time flow rate calculated using DP3'. Using the calibrated flow rate Q as the actual flow rate, the percentage error between the real-time flow rate and the actual flow rate is calculated.

[0229] The results show:

[0230] The calculated percentage error between the real-time traffic Q1' and the actual traffic is (-6.67%) - (+5.19%).

[0231] The calculated percentage error between the real-time traffic Q2' and the actual traffic is (-7.49%) - (+5.84%).

[0232] The calculated percentage error between the real-time traffic Q3' and the actual traffic is (-5.31%) - (+6.72%).

[0233] Overall, using DP1, DP2, DP3 / DP1`, DP2`, and DP3` to fit and calculate real-time traffic all have a good error range and can obtain relatively accurate results.

[0234] Therefore, DP1, DP2, and DP3 are used to calculate the flow rate. The three are redundant with each other. If one part fails or becomes inaccurate, there is still an effective replacement scheme, thereby improving the reliability and service life of underwater metering.

[0235] Plot the percentage errors corresponding to Q1', Q2', and Q3' against the actual flow rates on a coordinate system. The results are as follows: Figure 14 , 15 As shown in Figure 16, from Figure 14 , 15 As can be seen from 16:

[0236] When the flow rate is low, the percentage error obtained by fitting and calculating DP2 / DP2' is relatively more concentrated and the error range is relatively smaller, while the percentage error obtained by fitting and calculating DP1 / DP1' or DP3 / DP3' is relatively more dispersed and the error range is relatively larger.

[0237] When the flow rate is large, the percentage error obtained by fitting and calculating DP1 / DP1` or DP3 / DP3` is relatively more concentrated and the error range is relatively smaller, while the percentage error obtained by fitting and calculating DP2 / DP2` is relatively more dispersed and the error range is relatively larger.

[0238] Therefore, different fitting and / or calculation methods can be used to segment and measure real-time flow based on the target flow rate. The key to segmentation is finding the boundary between large and small flow rates. This boundary is generally set manually based on calibration results, and the boundary is the segmented flow rate value Q. f .

[0239] Therefore, when measuring and controlling real-time flow, the target flow rate Q can be used as a reference. m Real-time flow rate Q` and segmented metered flow rate Q f The magnitude of the differential pressure and the corresponding flow rate formula are selected to calculate the real-time flow rate, so as to obtain a more accurate result. That is, segmented control is performed as described in Example 2. That is, when the flow rate to be controlled is small, the control effect of needle valve assembly 5 is relatively better. In practice, it can accurately control the flow rate in the range of 0.18-10L / h. When the flow rate to be controlled is large, the needle valve is close to fully open, the control effect of needle valve assembly 5 is weakened, and the control effect of pressure reducing component 2 is relatively stronger, which is better for controlling a large range of flow rates (10-180L / h). The two work together to increase the flow range.

[0240] To simplify the fitting process of the flow rate Q-differential pressure DP relationship and the flow coefficient K-aperture V relationship in the early stages (reducing the number of calibrations and data processing), the calibration flow rate and the segmented metered flow rate Q can be used in the early stages. f The flow rate Q-differential pressure DP relationship and the flow coefficient K-aperture V relationship are piecewise fitted based on the magnitude of the flow rate Q. Later, the target flow rate Q is then used as the basis for further fitting. m With segmented flow rate value Q f The real-time flow Q` is calculated in segments based on the size of the data; that is, segmented fitting and segmented control are performed as described in Example 3.

[0241] Beneficial effects: By adopting the technical solution of this invention, the relationship between flow rate, valve opening, and differential pressure is established through preliminary calibration; in the subsequent actual production process, by adjusting the control valve opening and obtaining the real-time differential pressure, the real-time flow rate can be obtained quickly and accurately, ensuring stable and accurate drug injection metering.

[0242] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A redundancy control calculation method for an underwater chemical agent injection device, comprising a device body, wherein the device body includes an agent input connector (1), a pressure reducing component (2), a needle valve assembly (5), and an agent output connector (3) connected sequentially through a flow channel, characterized in that... Follow these steps: Step 1: Control the opening degree V of the needle valve assembly (5) to be fixed. Using the drug input connector (1) as the inlet, inject drugs with different calibration flow rates Q into the device body for calibration. During this period, simultaneously obtain the front section differential pressure DP1 before and after the drug flows through the pressure reducing component (2), the rear section differential pressure DP2 before and after the drug flows through the needle valve assembly (5), and the overall differential pressure DP3 before and after the drug flows through both the pressure reducing component (2) and the needle valve assembly (5). The calibration array consists of the calibrated flow rate Q, the front differential pressure DP1, the rear differential pressure DP2, and the overall differential pressure DP3 under the same opening V. Step 2: Fit the flow rate-differential pressure relationship under the same opening degree V using formula ①; in: K is the flow coefficient; DPn can be DP1, DP2, or DP3; C is the calibration coefficient; Step 3: Adjust the needle valve assembly (5) to different opening degrees V, repeat Step 1 and Step 2, and obtain the flow-differential pressure relationship under different opening degrees V; This yields several fitting arrays corresponding to "opening degree V - rated flow rate Q - flow coefficient K - rated coefficient C"; Step 4: Fit the relationship between the flow coefficient K and the opening V using formula ②; K = f(V), Formula ②; Step 5: Substitute formula ② into formula ① to obtain the formulas for flow rate, opening degree, and differential pressure, as shown in formula ③: The mean of several calibration coefficients C; Step 6: Connect the equipment body to the production system and introduce the reagent, setting the target flow rate Q. m Adjust the real-time opening V` of the needle valve assembly (5) from small to large, and during this period, obtain the real-time front section differential pressure DP1` before and after the drug flows through the pressure reducing element (2), the real-time rear section differential pressure DP2` before and after the drug flows through the needle valve assembly (5), and the real-time overall differential pressure DP3` before and after the drug flows through the pressure reducing element (2) and the needle valve assembly (5) at the same time. Calculate the real-time flow Q` using the following formula ④ until the real-time flow Q` equals the target flow Q. m ; Wherein: DPn` can be DP1`, DP2`, or DP3`.

2. The redundancy control calculation method for underwater chemical agent injection equipment according to claim 1, characterized in that: In step two, the segmented metering flow rate value Q is set. f ; When Q m >Q f If DPn in step two is either DP1 or DP1, then DPn` in step six is ​​either DP1`; if DPn in step two is either DP3 or DP3, then DPn` in step six is ​​either DP3`. When Q m ≤Q f If DPn takes DP2 in step two, then DPn` takes DP2` in step six.

3. The redundancy control calculation method for underwater chemical agent injection equipment according to claim 2, characterized in that: In step two, the segmented flow rate value Q is used. f Based on the standard, the calibration array is partitioned according to the calibrated flow rate Q, and the flow rate-differential pressure relationship under the same opening V is fitted piecewise using formula ①; in: When Q > Q f When DPn takes the form of DP1 or DP3; When Q≤Q f When DPn takes the value DP2; Q min <Q f <Q max ; Q min The minimum calibrated flow rate Q injected into the device body; Q max The maximum calibrated flow rate Q injected into the device body; In step three, the needle valve assembly (5) is adjusted to different opening degrees V, and steps one and two are repeated, while maintaining the segmented metering flow rate value Q. f By keeping the opening V constant, we obtain the segmented relationship between flow rate and differential pressure under different opening degrees V; In step four, the segmented flow rate value Q is used. f Using the standard, the fitting array is partitioned according to the magnitude of the calibrated flow rate Q, and the relationship between the flow coefficient K and the opening V is fitted piecewise using formula ②; In step five, formula ② is substituted into formula ① to obtain the segmented formulas for flow rate, opening degree, and differential pressure.

4. The redundancy control calculation method for underwater chemical agent injection equipment according to claim 1, 2, or 3, characterized in that: In step four; K=f(V)=A*V+D, formula ②; Where A and D are both parameters for fitting the opening degree.

5. The redundancy control calculation method for underwater chemical agent injection equipment according to claim 1, 2, or 3, characterized in that: The device body also includes a first pressure sensor (61), a second pressure sensor (62), and a third pressure sensor; The first pressure sensor (61) is connected to the flow channel at the upstream end of the pressure reducing member (2) to measure the upstream fluid pressure P1 before the agent flows through the pressure reducing member (2); The second pressure sensor (62) is connected to the flow channel between the pressure reducing element (2) and the needle valve assembly (5) to measure the mid-section fluid pressure P2 after the drug flows through the pressure reducing element (2) and before the needle valve assembly (5); The third pressure sensor is connected to the flow channel of the downstream section of the needle valve assembly (5) to measure the downstream fluid pressure P3 after the drug flows through the needle valve assembly (5); DP1 = P1 - P2; DP2 = P2 - P3; DP3 = ​​P1 - P3.

6. The redundancy control calculation method for underwater chemical agent injection equipment according to claim 1, 2, or 3, characterized in that: The device body also includes a linear displacement sensor and a rotational displacement sensor; The sensing end of the linear displacement sensor and the sensing end of the rotational displacement sensor are both connected to the opening and closing part of the needle valve assembly (5).

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