Low-resistance liquid ammonia pump test pipeline and multi-measurement-point integrated detection assembly

Abstract

The application discloses a kind of low flow resistance liquid ammonia pump test pipeline and multiple measuring point integrated detection assembly, belong to liquid ammonia pump test technical field, including liquid ammonia pump main body, the liquid inlet of the liquid ammonia pump main body is connected liquid inlet test pipe by ball head sleeve, the lateral wall of the liquid inlet test pipe is equipped with liquid inlet test component, and the top of the liquid inlet test pipe is equipped with liquid inlet exhaust component;The liquid outlet of the liquid ammonia pump main body is equipped with liquid outlet test pipe by flange, the lateral wall of the liquid outlet test pipe is equipped with liquid outlet test component, and the top of the liquid outlet test pipe is equipped with liquid outlet exhaust component;The liquid outlet test pipe is equipped with regulating valve in the downstream pipe section of liquid outlet test component fluid.This application adopts equal-diameter straight-through type liquid inlet test pipe and liquid outlet test pipe, cancels reducing, right-angle elbow and excess throttling structure, reduces pipeline resistance and local resistance, avoids pipeline additional pressure drop interference pump performance test, improves the test precision of flow-lift, net positive suction head and other parameters.

Description

Technical Field

[0001] This invention belongs to the field of liquid ammonia pump testing technology, specifically relating to a low flow resistance liquid ammonia pump testing pipeline and a multi-point integrated testing component. Background Technology

[0002] Liquid ammonia pumps are specialized industrial pumps designed for transporting liquid anhydrous ammonia (NH3). They are suitable for the low-temperature, high-saturation vapor pressure, easy flash vaporization, toxicity, Class II flammability, and corrosive properties of liquid ammonia media, and are widely used in fertilizer, urea synthesis, industrial refrigeration, hydrogen energy storage and supply, flue gas denitrification, and fine chemical synthesis. They are primarily used for pressurizing, circulating, and quantitatively dispensing liquid ammonia. In accordance with national standards GB / T 3.216 (Hydraulic Performance Acceptance Test of Rotary Power Pumps) and T / ZZB 2819—2022, closed-loop test pipelines must be constructed for both factory shipment and type testing of liquid ammonia pumps. Key performance parameters such as flow rate, inlet and outlet pressure, medium temperature, net positive suction head (NPSH), and vibration are simultaneously measured to calibrate core indicators such as pump hydraulic efficiency and effective NPSH.

[0003] However, existing liquid ammonia pump test pipelines generally suffer from several structural defects. First, conventional test pipelines extensively employ reducers, right-angle elbows, and segmented flange splicing structures, resulting in excessive local and frictional resistance. This leads to additional pressure drops, reducing the effective pump inlet pressure and exacerbating the tendency for liquid ammonia to vaporize due to excessively low local pressure. Simultaneously, pipeline resistance losses are superimposed on the pump's measured head, causing test data such as flow-head curves and net positive suction head (NPSH) to deviate from the pump's actual performance, affecting the accuracy and consistency of factory calibration results. Second, the pressure and temperature of the medium at different testing points are not synchronized. The time difference in the collected signals leads to a large cumulative error when calculating the cavitation pressure difference using the background program, making it difficult to accurately determine the effective net positive suction head (NPSH) of the pump. Furthermore, the use of distributed threaded connectors for various types of sensors involves multiple sealing operations during disassembly and assembly. Replacing different models of liquid ammonia pumps requires rearranging the detection elements and calibrating the measuring points, resulting in a long test preparation cycle, low efficiency in batch factory testing, and inability to meet production cycle requirements. In addition, the low integration level of the test pipeline and the loose layout of functional components hinder the synchronous acquisition and rapid comparison of test data, thus limiting the accuracy and efficiency of liquid ammonia pump performance testing. Summary of the Invention

[0004] The purpose of this invention is to provide a low-flow-resistance liquid ammonia pump test pipeline and a multi-point integrated detection component. By using a constant-diameter straight-through pipeline structure, the additional resistance caused by diameter changes and bends is eliminated. Combined with the differentiated integrated measurement point design at the inlet and outlet, the synchronous acquisition of signals from various sensors is achieved. This solves the problems of high flow resistance in existing test pipelines leading to performance data distortion and dispersed measurement points causing timing errors, thereby improving the accuracy and detection efficiency of liquid ammonia pump performance testing.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A low-flow-resistance liquid ammonia pump test pipeline and a multi-point integrated detection component, comprising: The main body of the liquid ammonia pump has an inlet and an outlet; The liquid inlet test tube is connected to the liquid inlet of the liquid ammonia pump body via a ball-head ferrule; The liquid outlet test tube is connected to the liquid outlet of the liquid ammonia pump body via a ball joint sleeve, and a regulating valve is connected in series in the downstream section of the liquid outlet test tube. A liquid inlet test assembly is disposed on the side wall of the liquid inlet test tube and is used to detect the parameters of the liquid inlet fluid in the liquid inlet test tube; A liquid discharge test assembly is disposed on the side wall of the liquid discharge test tube and is used to detect the liquid discharge parameters in the liquid discharge test tube; A liquid inlet and exhaust assembly is located at the top of the liquid inlet test tube and is used to collect and exhaust gas from the liquid inlet side fluid. A liquid discharge and venting assembly is installed at the top of the liquid discharge test tube to collect and discharge gas from the liquid discharge side fluid. The system includes a controller, which is electrically connected to the liquid inlet test assembly, the liquid outlet test assembly, and the regulating valve, respectively, for receiving detection signals and controlling the operation of the regulating valve; the liquid inlet test tube and the liquid outlet test tube are both straight-through tube structures, and the liquid inlet venting assembly and the liquid outlet venting assembly have the same structure.

[0007] This invention reduces fluid flow resistance through a straight-through pipe structure, avoids local pressure loss, and ensures the authenticity of the test conditions. Independent test components and exhaust components are set on the inlet and outlet sides, enabling synchronous zonal detection of fluid parameters on both sides, which can comprehensively reflect the operating status of the liquid ammonia pump. The controller realizes automated data acquisition and valve control without manual intervention, improving test efficiency and operational safety.

[0008] Preferably, the liquid inlet testing assembly includes a liquid inlet integrated mounting plate fixedly disposed on the outer wall of the liquid inlet testing tube. A liquid inlet pressure sensor is mounted on the liquid inlet integrated mounting plate for detecting the liquid inlet pressure. Multiple mounting holes are formed on the wall of the liquid inlet testing tube, and a rubber sealing gasket is provided in each mounting hole. The rubber sealing gasket is sandwiched between the hole wall and the outer wall of the corresponding detection element. The liquid inlet integrated mounting plate provides a unified mounting platform for multiple detection elements, avoiding the weakening of the tube wall strength caused by scattered openings. Multiple mounting holes allow for flexible and adjustable sensor configuration, improving versatility and expandability. The rubber sealing gasket forms an elastic sealing structure, effectively preventing liquid ammonia leakage and absorbing the impact of pipeline vibration on the detection element, ensuring the stability of the test data and the long-term reliability of the seal.

[0009] Preferably, the inlet integrated mounting plate is also equipped with an inlet temperature sensor and a cavitation differential pressure transmitter. The inlet temperature sensor is used to detect the inlet temperature, and the cavitation differential pressure transmitter is used to detect the cavitation pressure difference on the inlet side. The detection ends of the inlet pressure sensor, inlet temperature sensor, and cavitation differential pressure transmitter all pass through the inlet integrated mounting plate and extend into the interior of the inlet test tube, and the end face of each detection end is flush with the inner wall of the inlet test tube. The inlet temperature sensor and pressure sensor work together to provide a complete data basis for cavitation margin calculation; the cavitation differential pressure transmitter monitors the pressure difference change in real time, can provide timely warning of cavitation risk, and can effectively prevent pump damage; the end face of each detection end is flush with the inner wall of the tube, avoiding disturbance of the fluid by the detection element, reducing local flow resistance, and preventing impurities from accumulating at the detection end, thus ensuring long-term detection accuracy.

[0010] Preferably, the liquid inlet integrated mounting plate is also equipped with a trace gas content detector and a liquid inlet vibration sensor. The trace gas content detector is used to detect the trace gas content in the liquid inlet fluid, and the liquid inlet vibration sensor is used to detect the vibration parameters of the liquid inlet test tube. The detection probe of the trace gas content detector passes through the liquid inlet integrated mounting plate and the corresponding mounting hole and extends into the flow channel of the liquid inlet test tube. The detection probe of the liquid inlet vibration sensor passes through the liquid inlet integrated mounting plate and the corresponding mounting hole and extends into the flow channel of the liquid inlet test tube. The trace gas content detector monitors the dissolved gas content in liquid ammonia in real time and can promptly alarm when it exceeds the standard, avoiding pump performance degradation or cavitation failure caused by excessive gas content. The liquid inlet vibration sensor monitors the pipe wall vibration in real time, and the health status of the pump core components can be judged by vibration signal analysis, providing a basis for predictive maintenance. Both probes extend into the flow channel to achieve in-situ detection, avoiding signal attenuation and measurement deviation caused by external installation.

[0011] Preferably, the liquid inlet and exhaust assembly includes an arc-shaped gas collecting groove continuously formed along the top of the inner wall of the liquid inlet test tube, which is used to collect gas from the fluid on the liquid inlet side; multiple narrow exhaust holes are provided through the arc-shaped gas collecting groove and the outer wall of the liquid inlet test tube; a sealed gas collecting chamber is fixedly provided at the top of the outer wall of the liquid inlet test tube, and each of the narrow exhaust holes is connected to the inner cavity of the gas collecting chamber; an ammonia-repellent membrane is detachably installed at the outlet end of the gas collecting chamber, which is a microporous gas-permeable and liquid-blocking membrane used to intercept liquid ammonia and allow gaseous ammonia to pass through. The arc-shaped gas collecting groove utilizes the principle that gas has a lower density than liquid ammonia and naturally floats, efficiently collecting bubbles without external power; multiple narrow exhaust holes achieve effective gas-liquid separation, preventing large amounts of liquid ammonia from gushing out; the sealed gas collecting chamber avoids the safety risk of direct gas emission; the ammonia-repellent membrane selectively allows gaseous ammonia to pass through while intercepting liquid ammonia, ensuring the exhaust function while preventing liquid ammonia leakage, thus improving the safety and environmental friendliness of the testing system.

[0012] Preferably, the liquid discharge testing assembly includes a liquid discharge integrated mounting plate fixedly disposed on the outer wall of the liquid discharge testing tube. A liquid discharge pressure sensor and a liquid discharge temperature sensor are mounted on the liquid discharge integrated mounting plate. The liquid discharge pressure sensor is used to detect the liquid discharge pressure, and the liquid discharge temperature sensor is used to detect the liquid discharge temperature. The detection ends of both the liquid discharge pressure sensor and the liquid discharge temperature sensor pass through the liquid discharge integrated mounting plate and extend into the interior of the liquid discharge testing tube, with the end face of each detection end flush with the inner wall of the liquid discharge testing tube. The liquid discharge pressure and temperature sensors acquire pump outlet data in real time, and combined with corresponding data from the inlet side, key performance parameters such as head and efficiency can be accurately calculated. The flushness of the detection end face with the inner wall of the tube ensures low flow resistance detection on the liquid discharge side, avoiding interference with the flow field. The liquid discharge integrated mounting plate makes the liquid discharge side structure compact and well-organized, which is conducive to the standardization and modular design of the testing system.

[0013] Preferably, the outlet integrated mounting plate is also equipped with a flow meter, an outlet vibration sensor, and an overpressure monitoring transmitter. The flow meter is used to detect the outlet flow rate, the outlet vibration sensor is used to detect the vibration parameters of the outlet test tube, and the overpressure monitoring transmitter is used to detect the overpressure state on the outlet side. The detection end of the outlet vibration sensor passes through the outlet integrated mounting plate and extends into the interior of the outlet test tube, and the detection end of the overpressure monitoring transmitter also passes through the outlet integrated mounting plate and extends into the interior of the outlet test tube. The flow meter measures the outlet flow rate in real time, and combined with pressure parameters, it can comprehensively evaluate the pump's volumetric efficiency and overall performance. The outlet vibration sensor and the inlet vibration sensor form a dual-sided vibration monitoring system, and through comparative analysis, it can accurately determine fault types such as bearing wear, impeller imbalance, and cavitation. The overpressure monitoring transmitter monitors whether the outlet pressure exceeds the limit in real time, and, in conjunction with the controller, realizes emergency shutdown or automatic pressure relief, improving the safety protection level of the testing system.

[0014] Preferably, the valve stem of the regulating valve is equipped with an opening displacement sensor, which is fixedly connected to the valve stem and electrically connected to the controller to transmit the valve stem displacement signal to the controller. The opening displacement sensor detects the valve stem displacement in real time, accurately reflecting the actual opening of the regulating valve, avoiding control deviations caused by relying solely on control signals to infer the valve position, and achieving closed-loop precise control of the liquid flow rate. The sensor and controller form a real-time feedback loop, which can automatically adjust the opening according to preset operating conditions, improving the response speed and accuracy of flow regulation. It also has valve position status monitoring and fault diagnosis capabilities, and can promptly alarm when the valve stem is stuck or drifting.

[0015] Preferably, the controller is a programmable logic controller (PLC) or an embedded microcontroller. The signal input terminals of the controller are electrically connected to the inlet pressure sensor, inlet temperature sensor, cavitation differential pressure transmitter, trace gas detector, inlet vibration sensor, outlet pressure sensor, outlet temperature sensor, flow meter, outlet vibration sensor, overpressure monitoring transmitter, and opening displacement sensor, respectively. The control output terminal of the controller is electrically connected to the actuator of the regulating valve. The PLC or embedded microcontroller in this invention possesses industrial-grade reliability and anti-interference capabilities, adapts to harsh testing conditions, and ensures long-term stable system operation. The controller centrally collects all sensor signals, avoiding data asynchrony and human error caused by scattered instrument readings. The control output terminal connects to the regulating valve actuator to form a complete closed loop, enabling the system to automatically complete continuous multi-condition testing according to a preset program, improving testing efficiency and data consistency.

[0016] Preferably, the controller has a built-in data acquisition module and a comparison and judgment module. The data acquisition module is used to collect the detection signals of each sensor in real time and generate a monitoring dataset. The comparison and judgment module is used to compare the monitoring dataset with a preset threshold range. When any detection signal exceeds the corresponding preset threshold range, the controller outputs an alarm signal to an external alarm device or a host computer. In this invention, the data acquisition module collects all sensor signals synchronously in real time and generates a unified dataset, ensuring strict correspondence of each parameter on the time axis and providing a high-quality data foundation for performance calculation and fault analysis. The comparison and judgment module automatically compares the real-time data with the preset threshold, and outputs an alarm when any exceeds the limit, realizing 24-hour uninterrupted automatic monitoring. Outputting an alarm signal to an external alarm device or host computer allows testers to be aware of abnormalities immediately and take emergency measures, preventing equipment damage and media leakage, and improving the intrinsic safety level of the test system.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention employs a constant-diameter straight-through inlet and outlet test pipe, eliminating reducers, right-angle bends, and redundant throttling structures from the pump inlet to outlet. This ensures a consistent inner diameter throughout the entire length of the pipe, preventing abrupt changes in the flow cross-section and forced flow direction when the medium flows through it. This reduces frictional and local resistance, avoids the additional pressure drop caused by reducers and bends affecting the effective pump inlet pressure, and reduces the tendency for liquid ammonia to flash vaporize due to excessive local resistance. The reduced flow resistance means the test pipe itself no longer contributes to the measured pump head. The test results for key parameters such as the flow-head curve and net positive suction head (NPSH) are closer to the actual hydraulic performance of the pump, eliminating interference from pipe structure factors and improving the authenticity and reliability of calibration results during factory testing and type testing.

[0018] 2. This invention adopts a differentiated integrated measuring point design at the inlet and outlet. Pressure sensors, temperature sensors, cavitation differential pressure sensors, trace gas content monitoring elements, and vibration detection elements are centrally integrated on the pump inlet side. This is specifically designed to meet the multi-parameter collaborative monitoring requirements of cavitation state on the pump suction side, comprehensively capturing real-time changes in medium pressure, temperature, gas content, and pump vibration at the pump inlet. Flow sensors and overpressure monitoring elements are centrally integrated on the pump outlet side, matching the pump output performance and pipeline safety monitoring requirements. All detection elements on the inlet and outlet sides are integrated and installed on corresponding measuring point mounting bases. Signals collected by each sensor are synchronously triggered by the same data acquisition module, eliminating conversion errors caused by signal acquisition time differences in traditional distributed sensor layouts. This improves the accuracy of detecting cavitation differential pressure, pump efficiency, and performance curves. Simultaneously, the integrated measuring point design facilitates sensor docking and disassembly when replacing different models of liquid ammonia pumps, shortening the test preparation cycle and adapting to the production cycle requirements of batch factory testing. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a low flow resistance liquid ammonia pump test pipeline and a multi-point integrated detection component according to the present invention. Figure 2 This is a schematic diagram of the liquid inlet test tube structure of the present invention; Figure 3 This is a schematic diagram of the liquid inlet testing component structure of the present invention; Figure 4 This is a schematic diagram of the liquid discharge testing component structure of the present invention; Figure 5 This is a schematic diagram of the planar structure of the present invention; Figure 6 This is a block diagram of the circuit structure with the controller as the core in this invention.

[0020] In the diagram: 1. Liquid ammonia pump body; 2. Inlet test tube; 3. Inlet test assembly; 4. Inlet vent assembly; 5. Outlet test tube; 6. Outlet test assembly; 7. Outlet vent assembly; 8. Control valve; 9. Controller; 301. Inlet integrated mounting plate; 302. Inlet pressure sensor; 303. Inlet temperature sensor; 304. Cavitation differential pressure transmitter; 305. Trace gas content detector; 306. Inlet vibration sensor; 307. Mounting hole; 401. Gas collection tank; 402. Vent hole; 403. Gas collection chamber; 404. Ammonia-repellent membrane; 601. Outlet integrated mounting plate; 602. Outlet pressure sensor; 603. Outlet temperature sensor; 604. Flow meter; 605. Outlet vibration sensor; 606. Overpressure monitoring transmitter. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0022] like Figures 1-6 As shown, the present invention provides a low flow resistance liquid ammonia pump test pipeline and a multi-point integrated detection component. Its overall system architecture is as follows: including liquid ammonia pump body 1, inlet test pipe 2, outlet test pipe 5, inlet test component 3, outlet test component 6, inlet venting component 4, outlet venting component 7, regulating valve 8, and controller 9.

[0023] The liquid ammonia pump body 1, as the test object, has an inlet and an outlet. The inlet is equipped with an inlet test tube 2 via a ball joint ferrule connection, and the outlet is equipped with an outlet test tube 5 via a ball joint ferrule connection. The ball joint ferrule connection facilitates quick disassembly and sealing of the pipeline, which is suitable for the operational needs of frequently changing pipelines or pump bodies during the liquid ammonia pump test.

[0024] Both the inlet test pipe 2 and the outlet test pipe 5 are straight-through pipe structures, meaning that the centerline of the pipe is straight and the pipe diameter remains constant along the flow direction. The straight-through pipe structure eliminates the local resistance loss introduced by bends, reducers, or tees in traditional test pipelines, allowing the fluid to flow through the test section with the lowest pressure drop. This ensures the authenticity of the pressure measurements at the inlet and outlet of the liquid ammonia pump and avoids misjudgments of pump head, efficiency, and other performance parameters caused by additional pipeline resistance.

[0025] A regulating valve 8 is connected in series in the downstream section of the liquid outlet test pipe 5. The regulating valve 8 is used to regulate the liquid ammonia pump's outlet flow rate to simulate the pump's operating state under different load conditions. The regulating valve 8 can be adjusted manually or automatically, and its specific selection can be a gate valve, ball valve, or electric regulating valve, etc., which have good regulating characteristics.

[0026] The liquid inlet test assembly 3 is fixedly installed on the side wall of the liquid inlet test tube 2 and is used to detect the liquid inlet fluid parameters in the liquid inlet test tube 2. These parameters include, but are not limited to, liquid inlet pressure, liquid inlet temperature, cavitation pressure difference, fluid gas content, and tube wall vibration. The liquid outlet test assembly 6 is fixedly installed on the side wall of the liquid outlet test tube 5 and is used to detect the liquid outlet fluid parameters in the liquid outlet test tube 5. These liquid outlet fluid parameters include, but are not limited to, liquid outlet pressure, liquid outlet temperature, liquid outlet flow rate, tube wall vibration, and overpressure state.

[0027] The liquid inlet and exhaust venting assembly 4 is located at the top of the liquid inlet test tube 2 and is used to collect and exhaust the gas entrained in the liquid inlet side fluid; the liquid outlet and exhaust venting assembly 7 is located at the top of the liquid outlet test tube 5 and is used to collect and exhaust the gas entrained in the liquid outlet side fluid. The liquid inlet and exhaust venting assembly 4 and the liquid outlet and exhaust venting assembly 7 have the same structure. This symmetrical design simplifies the structural complexity of the system, reduces manufacturing costs and maintenance difficulty, and ensures the consistency of exhaust performance on both sides.

[0028] The controller 9 is electrically connected to the liquid inlet test component 3, the liquid outlet test component 6, and the regulating valve 8, respectively. It receives detection signals from each detection element and outputs control commands to the regulating valve 8 according to preset control logic, thereby automatically adjusting the opening of the regulating valve 8. The controller 9 upgrades the entire testing system from the traditional operation mode of manual reading and adjustment to an automated data acquisition and closed-loop control mode, significantly improving testing efficiency and data consistency.

[0029] The liquid inlet testing component 3 is the core module for realizing integrated detection of multiple parameters on the liquid inlet side, and its specific structure is as follows: The liquid inlet test assembly 3 includes a liquid inlet integrated mounting plate 301, which is fixedly installed on the outer wall of the liquid inlet test tube 2. The liquid inlet integrated mounting plate 301 can be fixed to the outer wall of the liquid inlet test tube 2 by welding, threaded connection or clamp connection. Its material should be stainless steel or alloy material compatible with liquid ammonia medium to ensure corrosion resistance and structural strength in low temperature liquid ammonia environment. The liquid inlet integrated mounting plate 301 has multiple through mounting holes, each used to install different types of detection elements. The hole diameter and hole spacing are standardized according to the specifications of the assembled sensor.

[0030] The liquid inlet integrated mounting plate 301 is equipped with a liquid inlet pressure sensor 302, which is used to detect the liquid inlet pressure in the liquid inlet test tube 2. The liquid inlet pressure sensor 302 can be a piezoresistive, capacitive, or resonant pressure sensing element, and its range should be selected according to the rated inlet pressure of the liquid ammonia pump, typically from -0.1MPa to 2.5MPa. The liquid inlet pressure sensor 302 can output an electrical signal proportional to the liquid inlet pressure in real time. This electrical signal is amplified and filtered by the signal conditioning circuit and then transmitted to the controller 9.

[0031] The liquid inlet integrated mounting plate 301 is also equipped with a liquid inlet temperature sensor 303. The liquid inlet temperature sensor 303 is used to detect the liquid inlet temperature inside the liquid inlet test tube 2. The liquid inlet temperature sensor 303 can be a temperature sensing element such as a thermocouple, resistance temperature detector (RTD), or thermistor. Its measurement range should cover the temperature variation range of liquid ammonia under test conditions, typically -50°C to +80°C. The liquid inlet temperature sensor 303 works in conjunction with the liquid inlet pressure sensor 302, and the combined data provided by the two can be used to calculate key thermodynamic parameters of liquid ammonia, such as density, saturated vapor pressure, and net positive suction head (NPSH).

[0032] The liquid inlet integrated mounting plate 301 is also equipped with a cavitation differential pressure transmitter 304. The cavitation differential pressure transmitter 304 is used to detect the cavitation pressure difference on the liquid inlet side. By measuring the difference between the total pressure and static pressure of the fluid at the inlet of the liquid ammonia pump and combining it with the liquid inlet temperature data, the cavitation differential pressure transmitter 304 can accurately determine whether the liquid ammonia pump is in a critical cavitation state under the current operating conditions. When the detected cavitation pressure difference is lower than the preset safety threshold, the system can determine that the cavitation risk has increased, thereby providing an early warning.

[0033] The liquid inlet integrated mounting plate 301 is also equipped with a trace gas detector 305. This trace gas detector 305 is used to detect the trace gas content in the liquid inlet fluid. The content of dissolved gas in liquid ammonia directly affects the suction performance and cavitation characteristics of the liquid ammonia pump. The trace gas detector 305 achieves accurate measurement of the volume fraction of tiny bubbles or dissolved gas in liquid ammonia through principles such as optical scattering, ultrasonic attenuation, or changes in conductivity. Its detection accuracy can reach the ppm level.

[0034] The liquid inlet integrated mounting plate 301 is also equipped with a liquid inlet vibration sensor 306, which is used to detect the vibration parameters of the liquid inlet test tube 2, including vibration amplitude, vibration frequency, and vibration acceleration. The liquid inlet vibration sensor 306 can be a piezoelectric accelerometer or a MEMS gyroscope, and its frequency response range should cover the characteristic frequency of the liquid ammonia pump and its harmonic components, typically from 10Hz to 10kHz.

[0035] The liquid inlet test tube 2 has multiple mounting holes 307 on its wall. The number and position of the mounting holes 307 correspond one-to-one with the detection elements on the liquid inlet integrated mounting plate 301. Each mounting hole 307 is provided with a rubber sealing gasket. The rubber sealing gasket is sandwiched between the hole wall of the mounting hole 307 and the outer wall of the corresponding detection element to form an elastic sealing structure. The rubber sealing gasket has moderate elasticity and resistance to liquid ammonia corrosion. It can effectively prevent liquid ammonia from leaking outward along the gap of the mounting hole and absorb the impact of pipeline vibration on the rigid connection part of the detection element, thus extending the service life of the detection element.

[0036] The detection ends of the inlet pressure sensor 302, inlet temperature sensor 303, and cavitation differential pressure transmitter 304 all pass through the corresponding mounting holes of the inlet integrated mounting plate 301 and extend into the interior of the inlet test tube 2, with the end face of each detection end flush with the inner wall of the inlet test tube 2. This flush installation method has three technical advantages: First, the detection end does not protrude from the inner wall of the pipe, eliminating the throttling effect and eddy current disturbance of the fluid by the detection element in the traditional insertion installation method, effectively reducing local flow resistance; Second, the flush end face does not form a fluid stagnation zone or backflow dead zone, preventing trace impurities that may be entrained in liquid ammonia from depositing and scaling on the detection end surface, ensuring detection accuracy and response speed for long-term use; Third, the flushness of the detection end with the inner wall of the pipe also avoids additional vibration and noise interference caused by the detection element extending into the flow channel, improving the measurement signal-to-noise ratio of the vibration sensor.

[0037] The detection probe of the trace gas content detector 305 passes through the liquid inlet integrated mounting plate 301 and its corresponding mounting hole 307 and extends into the flow channel of the liquid inlet test tube 2 to measure the gas content of the flowing liquid ammonia in a direct contact manner. The detection probe of the liquid inlet vibration sensor 306 passes through the liquid inlet integrated mounting plate 301 and its corresponding mounting hole 307 and extends into the flow channel of the liquid inlet test tube 2, directly contacting the tube wall to obtain a real vibration signal. Although the installation method of the detection probe extending into the flow channel has different flow resistance characteristics than flush installation, for gas content detection and vibration detection, this direct contact installation can obtain higher signal strength and faster response speed. The resulting improvement in measurement accuracy far outweighs the negligible increase in local flow resistance.

[0038] The liquid inlet and exhaust outlet assembly 4 is a key module for realizing automatic separation and exhaust of gas on the liquid inlet side, and its specific structure is as follows: The liquid inlet and exhaust assembly 4 includes a continuously extending arc-shaped gas collecting groove 401 along the top of the inner wall of the liquid inlet test pipe 2. The arc-shaped gas collecting groove 401 has an arc-shaped cross-section and extends continuously along the axial direction of the liquid inlet test pipe 2, with its opening position located at the top of the pipe cross-section. The design of the arc-shaped gas collecting groove 401 utilizes the physical principle that the gas density in a gas-liquid two-phase flow is lower than that of the liquid, and therefore naturally floats to the top of the pipe under the action of gravity. This allows the air bubbles in the liquid ammonia flowing through the liquid inlet test pipe 2 to continuously float up under the action of buoyancy and be captured and collected by the arc-shaped concave surface of the arc-shaped gas collecting groove 401. Compared with rectangular or V-shaped cross-sections, the arc-shaped gas collecting groove has a smaller flow dead zone and a smoother bubble guiding effect, while minimizing interference with the flow field of the mainstream liquid ammonia, further reducing the adverse effects of the exhaust structure on flow resistance.

[0039] Multiple narrow vent holes 402 are provided through the arc-shaped gas collecting groove 401 and the outer wall of the liquid inlet test tube 2. These narrow vent holes 402 are distributed along the axial direction of the liquid inlet test tube 2, and their diameter is optimized, typically ranging from 1mm to 3mm. This diameter range serves a dual function: firstly, it allows gaseous ammonia to pass smoothly, enabling timely gas discharge; secondly, the narrow diameter, under the surface tension of liquid ammonia, forms a liquid film at the orifice. This liquid film exhibits high flow resistance to liquid ammonia but low flow resistance to gaseous ammonia, thus achieving preliminary separation of the gas and liquid phases—allowing gas discharge while preventing a large amount of liquid ammonia from gushing out with the gas. The parallel arrangement of multiple narrow vent holes 402 also provides redundant venting channels. Even if individual vent holes are blocked by impurities, the remaining vent holes can still maintain normal venting function, improving the reliability and fault tolerance of the venting assembly.

[0040] A sealed gas collection chamber 403 is fixedly installed on the top of the outer wall of the liquid inlet test tube 2. Each narrow vent hole 402 is connected to the inner cavity of the gas collection chamber 403. The sealed gas collection chamber 403 is a hollow, sealed cavity with an internal volume larger than the sum of the volumes of each narrow vent hole 402. It can temporarily store the gas discharged from the liquid inlet test tube 2, serving as a gas buffer and pressure buffer. The airtightness of the sealed gas collection chamber 403 ensures that the discharged gaseous ammonia will not directly escape into the surrounding environment, thereby avoiding the safety risks of poisoning, combustion, or explosion that may be caused by liquid ammonia leakage.

[0041] The outlet of the gas collection chamber 403 is detachably equipped with an ammonia-repellent membrane 404. The ammonia-repellent membrane 404 is a microporous, gas-permeable, liquid-blocking membrane used to trap liquid ammonia and allow gaseous ammonia to pass through. The ammonia-repellent membrane 404 is preferably made of polytetrafluoroethylene (PTFE) or modified polyvinylidene fluoride (PVDF), a polymer material with good liquid repellency and chemical corrosion resistance. Its micropore size is typically 0.1 μm to 10 μm, a range that enables gas-liquid separation at the molecular scale. Gaseous ammonia molecules can freely diffuse to the outside through the micropores, while liquid ammonia molecules are effectively trapped inside the gas collection chamber 403 due to the combined effects of surface tension and the liquid repellency effect. The ammonia-repellent membrane 404 is installed in a detachable manner, such as with a threaded cap or flange clamping structure, facilitating quick replacement when the membrane reaches the end of its service life or becomes clogged, reducing maintenance costs. The outlet of the ammonia-repellent membrane 404 can be connected to a dedicated gas recovery pipeline or exhaust gas treatment device, or it can be vented to the atmosphere.

[0042] The liquid outlet testing component 6 is the core module for realizing integrated detection of multiple parameters on the liquid outlet side. Its specific structure corresponds to but differs from that of the liquid inlet testing component 3. The liquid discharge test assembly 6 includes a liquid discharge integrated mounting plate 601 fixedly installed on the outer wall of the liquid discharge test tube 5. The material, fixing method and mounting hole layout of the liquid discharge integrated mounting plate 601 are similar to those of the liquid inlet integrated mounting plate 301. It is also made of corrosion-resistant metal material compatible with liquid ammonia and has multiple standardized mounting holes for assembling various test elements.

[0043] The liquid outlet integrated mounting plate 601 is equipped with a liquid outlet pressure sensor 602 and a liquid outlet temperature sensor 603. The liquid outlet pressure sensor 602 is used to detect the liquid outlet pressure in the liquid outlet test tube 5, and the liquid outlet temperature sensor 603 is used to detect the liquid outlet temperature in the liquid outlet test tube 5. The ranges of the liquid outlet pressure sensor 602 and the liquid outlet temperature sensor 603 should be matched with the actual operating conditions on the outlet side of the liquid ammonia pump. Since the outlet pressure of the liquid ammonia pump is usually higher than the inlet pressure, the range of the liquid outlet pressure sensor 602 is generally selected from 0MPa to 6.0MPa or adapted according to the rated head of the pump. The range of the liquid outlet temperature sensor 603 is the same as that of the inlet temperature sensor 303.

[0044] The detection ends of the outlet pressure sensor 602 and the outlet temperature sensor 603 both pass through the corresponding mounting holes of the outlet integrated mounting plate 601 and extend into the interior of the outlet test tube 5, with the end face of each detection end flush with the inner wall of the outlet test tube 5. This flush mounting method also achieves low flow resistance detection on the outlet side, ensuring that the pressure value measured by the outlet pressure sensor 602 truly reflects the static pressure inside the outlet test tube 5, rather than the dynamic pressure component generated by the insertion disturbance of the detection element, thereby ensuring the accuracy of the head calculation.

[0045] The liquid outlet integrated mounting plate 601 is also equipped with a flow meter 604, which is used to detect the liquid flow rate in the liquid outlet test tube 5. The flow meter 604 can be an electromagnetic flow meter, vortex flow meter, ultrasonic flow meter, or Coriolis mass flow meter, etc., and its selection should comprehensively consider factors such as the conductivity of liquid ammonia, flow range, accuracy requirements, and installation space. Among them, electromagnetic flow meters have good applicability in liquid ammonia media because they have no moving parts, minimal pressure loss, and good resistance to the corrosiveness of liquid ammonia. The detection end of the flow meter 604 passes through the corresponding mounting hole of the liquid outlet integrated mounting plate 601 and extends into the liquid outlet test tube 5 to achieve in-situ measurement of the flow rate.

[0046] The liquid outlet integrated mounting plate 601 is also equipped with a liquid outlet vibration sensor 605. The liquid outlet vibration sensor 605 is used to detect the vibration parameters of the liquid outlet test tube 5. The detection end of the liquid outlet vibration sensor 605 passes through the corresponding mounting hole of the liquid outlet integrated mounting plate 601 and extends into the interior of the liquid outlet test tube 5, directly contacting the outer wall or the extension of the pipe wall of the liquid outlet test tube 5 to obtain the real vibration signal. The liquid outlet vibration sensor 605 cooperates with the liquid inlet vibration sensor 306 to form a dual-point vibration synchronous monitoring system on the liquid inlet side and the liquid outlet side. By comparing and analyzing the vibration amplitude, phase and spectrum of both sides, the fault type of the liquid ammonia pump can be more accurately located and identified: for example, when the vibration on the liquid inlet side is abnormally greater than that on the liquid outlet side, it may indicate that the liquid inlet pipeline is blocked or cavitation has occurred; when the vibration on the liquid outlet side is abnormally greater than that on the liquid inlet side, it may indicate that the liquid outlet pipeline is blocked or the regulating valve is faulty; when both sides show abnormal vibration and have the same characteristic frequency components, it may be a pump body fault.

[0047] The liquid outlet integrated mounting plate 601 is also equipped with an overpressure monitoring transmitter 606, which is used to detect the overpressure state on the liquid outlet side. The detection end of the overpressure monitoring transmitter 606 passes through the corresponding mounting hole of the liquid outlet integrated mounting plate 601 and extends into the interior of the liquid outlet test tube 5. The main difference between the overpressure monitoring transmitter 606 and the liquid outlet pressure sensor 602 is that the liquid outlet pressure sensor 602 is used to continuously measure the pressure value and convert it into an analog signal for use by the control system, while the overpressure monitoring transmitter 606 focuses on the judgment of the pressure threshold. It is equipped with a mechanical or electronic pressure switch. When the liquid outlet pressure exceeds the preset safety threshold, the overpressure monitoring transmitter 606 directly outputs a switch signal to trigger an emergency protection action, independent of the control loop of the controller 9, forming redundant safety protection. Even if the controller 9 fails, the overpressure monitoring transmitter 606 can still independently perform the overpressure protection function.

[0048] The regulating valve 8 is connected in series to the downstream section of the fluid outlet test pipe 5. Its specific structure and supporting detection device are as follows: The valve body of regulating valve 8 is connected to the outlet test tube 5 at both ends via flanges or welding. Inside the valve body are a valve core and a valve seat. Driven by the valve stem, the valve core moves relative to the valve seat, changing the flow cross-sectional area of ​​the valve orifice, thereby regulating the outlet flow rate. The driving method of regulating valve 8 can be selected from electric, pneumatic, or hydraulic actuators depending on the testing requirements. Electric actuators are preferred due to their good interface compatibility with the controller and high control accuracy. The electric actuator receives a 4-20mA current signal or a 0-10V voltage signal output from the controller 9 and drives the valve stem to rotate or move linearly via a servo motor, moving the valve core to the position corresponding to the input signal.

[0049] The valve stem of the regulating valve 8 is equipped with an opening displacement sensor, which is fixedly connected to the valve stem and electrically connected to the controller 9. This sensor transmits the valve stem displacement signal to the controller 9. The opening displacement sensor can be a potentiometer-type, magnetostrictive, or photoelectric coded displacement sensing element. Its measurement principle is to convert the linear or angular displacement of the valve stem into a proportional electrical signal. The opening displacement sensor is connected to the valve stem via a mechanical linkage or direct coupling. When the valve stem moves, it drives the sliding contact or rotary encoder of the sensor to rotate, thereby outputting an electrical signal corresponding to the current valve stem position in real time. This electrical signal is sampled by the analog input channel of the controller 9 and compared with the control command value issued by the controller 9 to form a closed-loop valve position control circuit.

[0050] The introduction of the aforementioned valve opening displacement sensor solves the inherent defects in traditional control valves, namely, the inference of valve position based solely on control signals without knowing the actual movement of the valve stem. When the valve stem fails to reach the target position due to changes in friction, media impact, or actuator aging, the system cannot detect this deviation. The real-time feedback signal from the valve opening displacement sensor allows the controller 9 to accurately determine the actual displacement of the valve stem and dynamically adjust the drive signal through closed-loop control algorithms such as PID control, achieving high-precision valve position control. Simultaneously, the signal from the valve opening displacement sensor can also be used for fault diagnosis of the control valve. When the controller 9 issues a control command but the valve opening displacement sensor signal shows no change or insufficient change within a preset time, the controller 9 can determine that the control valve 8 is stuck or that the actuator is malfunctioning, and output a corresponding fault alarm signal.

[0051] The controller 9 is the core of the entire test system for data processing and control. Its specific structure and functions are as follows: Controller 9 employs either a readily available, mature programmable logic controller (PLC) or an embedded microcontroller. PLCs offer high industrial reliability and abundant I / O interface resources, making them suitable for long-term stable operation in harsh environments such as electromagnetic interference, temperature fluctuations, and vibrations that may exist at liquid ammonia pump testing sites. Their modular hardware structure allows for flexible expansion of input / output channels based on the actual number of measurement points. Embedded microcontrollers, on the other hand, offer advantages such as small size, low cost, fast processing speed, and low power consumption, making them suitable for cost-sensitive or space-constrained testing scenarios. Their rich peripheral interfaces facilitate easy connection to various sensors and actuators. Regardless of the implementation method used, controller 9 should possess an industrial-grade operating temperature range (-40°C to +85°C) and sufficient electromagnetic interference immunity.

[0052] The signal input terminals of the controller 9 are electrically connected to the inlet pressure sensor 302, inlet temperature sensor 303, cavitation differential pressure transmitter 304, trace gas content detector 305, inlet vibration sensor 306, outlet pressure sensor 602, outlet temperature sensor 603, flow meter 604, outlet vibration sensor 605, overpressure monitoring transmitter 606, and opening displacement sensor, respectively. This complete electrical connection network enables the controller 9 to synchronously acquire the output signals of all detection elements, avoiding the unavoidable time asynchrony problem and manual recording errors that occur when multiple independent instruments are read separately. All sensor signals are amplified, filtered, and converted from analog to digital by the signal conditioning circuit inside the controller 9, and then converted into digital data in a unified format for subsequent data analysis and control calculations.

[0053] The control output terminal of the controller 9 is electrically connected to the actuator of the regulating valve 8. Based on preset test conditions and combined with currently measured flow and pressure feedback signals, the controller 9 calculates the target opening value of the regulating valve 8 using a built-in control algorithm. This target value is then converted into a corresponding control signal and output to the actuator of the regulating valve 8, driving the valve stem to the target position. The connection between the signal input terminal of the controller 9 and the opening displacement sensor of the regulating valve 8 forms an inner feedback loop, ensuring that the deviation between the actual valve stem displacement and the target value is minimized. The connection between the signal input terminal of the controller 9 and the flow meter 604 and the outlet pressure sensor 602 forms an outer feedback loop, ensuring that the final controlled variable of the system reaches the set value. This dual closed-loop control structure achieves high-precision automatic flow and pressure regulation.

[0054] The controller 9 has a built-in data acquisition module and a comparison and judgment module. The data acquisition module is used to collect the detection signals from each sensor in real time and generate a monitoring dataset. The acquisition frequency and resolution of the data acquisition module should be set according to the dynamic response characteristics of each sensor. For rapidly changing vibration signals, the acquisition frequency should not be lower than 1kHz; for slowly changing temperature signals, the acquisition frequency can be as low as 1Hz. After performing preprocessing operations such as digital filtering, unit conversion, and zero drift calibration on the acquired raw signals, the data acquisition module generates a structured monitoring dataset. This dataset is stored according to a preset sampling interval to form a continuous monitoring data record, which can be used for subsequent performance analysis, trend prediction, and fault tracing.

[0055] The comparison and judgment module is used to compare the monitoring dataset with a preset threshold range. When any detection signal exceeds the corresponding preset threshold range, the controller 9 outputs an alarm signal to an external alarm device or a host computer. The preset threshold range is stored in the non-volatile memory of the controller 9. The threshold values ​​of each detection parameter can be set and adjusted separately according to different liquid ammonia pump models, test conditions, and safety standards. For example, the lower limit threshold for inlet pressure should be higher than the saturated vapor pressure of liquid ammonia at the current temperature to prevent cavitation; the upper limit threshold for outlet pressure should be lower than the maximum allowable working pressure of the pipeline and seals; the vibration amplitude threshold should be set according to the normal operating vibration reference value of the pump; and the temperature threshold should be set according to the safe operating temperature range of liquid ammonia and the allowable temperature of the pump bearings.

[0056] When the comparison and judgment module detects that any parameter exceeds the threshold range, the controller 9 immediately outputs an alarm signal to an external alarm device or host computer. This alarm signal can be a drive signal for an audible and visual alarm, or a digital communication alarm message sent to the host computer or central control center. Simultaneously, based on the severity level of the alarm, the controller 9 can execute a tiered response strategy: for minor exceedances, only an alarm prompt is output and abnormal data is recorded; for moderate exceedances, an alarm signal is output while automatically adjusting the opening of the regulating valve 8 to attempt to restore the parameter to the normal range; for severe exceedances, an emergency stop signal is immediately output to the liquid ammonia pump drive system, and the regulating valve 8 is fully opened or fully closed to bring the system into a safe state. This multi-layered safety protection strategy prevents equipment damage, media leakage, and safety accidents caused by continuous operation with abnormal parameters, improving the intrinsic safety level of the testing system.

[0057] The working principle of this invention is as follows: This invention uses a liquid ammonia pump body 1 as the core device under test. The inlet test pipe 2 and outlet test pipe 5 are connected to the inlet and outlet of the liquid ammonia pump body 1 respectively via ball joint fittings. Together with a regulating valve 8 and an external circulation pipeline, they form a closed-loop test pipeline system. During test operation, the liquid ammonia medium, under the suction of the external circulation pump or the liquid ammonia pump body 1 itself, first enters the inlet of the liquid ammonia pump body 1 through the inlet test pipe 2. After the liquid ammonia pump body 1 starts, it pressurizes the medium. The pressurized high-pressure liquid ammonia is discharged from the outlet and enters the outlet test pipe 5. After flowing through the regulating valve 8 connected in series in the downstream section of the outlet test pipe 5, it returns to the external circulation system, forming a complete closed-loop test circuit. In this cycle, both the inlet test pipe 2 and the outlet test pipe 5 adopt a constant diameter straight-through pipe structure. The entire test pipe section has no diameter changes, no right-angle bends, and no unnecessary throttling structures. The flow cross-section remains consistent throughout the flow, and the flow direction does not undergo forced changes. The friction resistance and local resistance of the pipeline are maintained at a low level. The straight-through pipe structure avoids the additional pressure drop introduced by fittings such as elbows, reducers, or tees in traditional test pipelines. This ensures that the inlet pressure measured by the inlet pressure sensor 302 truly reflects the effective inlet pressure of the liquid ammonia pump body 1, rather than the pressure value attenuated due to additional pipeline resistance. This eliminates the impact of additional pressure drop on the accuracy of pump inlet effective pressure measurement, providing true and reliable raw data for the accurate calculation of subsequent key performance parameters such as net positive suction head (NPSH).

[0058] When liquid ammonia flows through the inlet test tube 2, the inlet test assembly 3, installed on the side wall of the inlet test tube 2, simultaneously starts multi-parameter acquisition. The inlet pressure sensor 302 detects the inlet pressure in the inlet test tube 2 in real time, the inlet temperature sensor 303 simultaneously detects the inlet temperature, the cavitation differential pressure transmitter 304 detects the cavitation differential pressure on the inlet side in real time, the trace gas detector 305 continuously detects the trace gas content in the inlet fluid, and the inlet vibration sensor 306 simultaneously detects the vibration amplitude and frequency parameters of the inlet test tube 2. All the above detection elements are fixedly mounted on the inlet integrated mounting plate 301, and each detection end extends into the internal flow channel of the inlet test tube 2 through the inlet integrated mounting plate 301 and the corresponding mounting hole 307. The detection ends of the inlet pressure sensor 302, inlet temperature sensor 303, and cavitation differential pressure transmitter 304 are all designed to be flush with the inner wall of the inlet test tube 2. The detection ends do not protrude into the flow channel, thus preserving the smoothness of the pipe's inner wall and avoiding any disturbance or obstruction to the flow of the medium. This eliminates the interference effect of the insertion of the detection element on the flow field while acquiring accurate pressure, temperature, and differential pressure signals, without generating any additional local resistance, ensuring the realization of low flow resistance characteristics on the inlet side. The detection probes of the trace gas content detector 305 and the inlet vibration sensor 306 also extend into the flow channel of the inlet test tube 2 through the inlet integrated mounting plate 301 and the corresponding mounting hole 307, directly contacting the flowing liquid ammonia to acquire high-fidelity gas content and vibration signals. Although this extended installation differs from the flush installation method in terms of flow resistance characteristics, it is necessary to obtain sufficient signal strength and fast response speed. The resulting slight increase in local resistance is within an acceptable engineering error range. All signals collected by the sensors are synchronously triggered by the same data acquisition module, ensuring that each detection signal is strictly synchronized in time and space. This eliminates the signal acquisition time difference problem that may be introduced by independent sampling of different sensors, and avoids the adverse effects of data asynchrony on the calculation accuracy of dynamic performance parameters such as net positive suction head (NPSH) and pump efficiency. It provides a high-precision synchronous data foundation for the performance analysis and fault diagnosis of the liquid ammonia pump body 1.

[0059] When the medium flows through the outlet test tube 5, the outlet test assembly 6, located on the side wall of the outlet test tube 5, simultaneously acquires multiple parameters on the outlet side. The outlet pressure sensor 602 detects the outlet pressure in the outlet test tube 5 in real time, the outlet temperature sensor 603 simultaneously detects the outlet temperature, the flow meter 604 continuously detects the outlet flow rate, the outlet vibration sensor 605 simultaneously detects the vibration parameters of the outlet test tube 5, and the overpressure monitoring transmitter 606 monitors in real time whether the pressure on the outlet side exceeds the safety threshold. The detection ends of all the above-mentioned detection elements extend into the pipe flush with the inner wall, without interfering with the flow field or adding additional local resistance, thus ensuring the accuracy of the outlet pressure and temperature measurements and low flow resistance characteristics. Depending on the selection, the flow meter 604 can employ electromagnetic, vortex, or ultrasonic principles. Its continuous and accurate measurement of large-flow liquid ammonia provides crucial flow data for calculating the volumetric efficiency and plotting the performance curves of the liquid ammonia pump body 1. The discharge vibration sensor 605 and the inlet vibration sensor 306 constitute a synchronous vibration monitoring system for both the inlet and outlet sides. By comparing and analyzing the amplitude, frequency and phase of the vibration signals on both sides, it is possible to determine in real time during the test whether there are typical fault modes such as bearing wear, impeller imbalance, shaft bending, coupling misalignment or abnormal vibration induced by cavitation in the main body 1 of the liquid ammonia pump, thus realizing in-situ online diagnosis of the pump's operating status.

[0060] The regulating valve 8 is connected in series in the downstream section of the outlet test pipe 5 and is the key actuator in the test loop for flow regulation and operating condition switching. During the test operation, the controller 9 calculates the target opening value of the regulating valve 8 based on the preset test conditions, combined with the real-time flow signal fed back by the flow meter 604 and the real-time pressure signal fed back by the outlet pressure sensor 602. This target value is then converted into a standard 4-20mA control current signal and output to the electric actuator of the regulating valve 8, driving the valve stem to rotate and move the valve core to the target position. This changes the flow cross-sectional area of ​​the valve orifice, achieving precise regulation of the outlet flow of the liquid ammonia pump body 1. Simultaneously with flow regulation, the opening displacement sensor detects the actual displacement of the valve stem in real time and feeds the signal back to the controller 9. This, together with the target opening command output by the controller 9, forms an inner loop feedback loop for the valve position, ensuring that the deviation between the actual position and the target position of the valve stem is minimized. Meanwhile, the signals from the flow meter 604 and the outlet pressure sensor 602, along with the set value, form an outer loop feedback loop, ensuring that the final controlled variable of the system accurately reaches the target value. This dual closed-loop control structure enables the regulating valve 8 to automatically and stably switch between multiple different flow rate operating points according to a preset test program during the test, without manual intervention. This significantly improves the testing efficiency of liquid ammonia pump performance curve mapping and the repeatability accuracy of operating condition switching. The actual valve stem displacement signal provided by the opening displacement sensor can also serve as a basis for valve status diagnosis. When the controller 9 issues a regulation command but the displacement sensor signal does not respond or the response is insufficient within a preset time, the system can promptly determine that the regulating valve 8 is stuck or that the actuator is malfunctioning and output an alarm.

[0061] During the flow of the test medium, liquid ammonia may produce a small amount of vaporized or dissolved gas in the circulation system due to temperature changes, pressure fluctuations, or local negative pressure on the pump suction side. These trace gases will gradually rise under gravity and accumulate in the top area of ​​the pipe cross-section. The liquid inlet and exhaust outlet assembly 4 effectively captures the gas that rises and gathers at the top of the pipe through the arc-shaped gas collecting groove 401 continuously opened along the top of the inner wall of the liquid inlet test pipe 2. The arc-shaped gas collecting groove provides a smooth bubble guiding channel, allowing the gas to flow along the gas collecting groove to the position of multiple micro-narrow exhaust holes 402. The micro-narrow exhaust holes 402 utilize the different flow resistance characteristics of the micropore size to the gas and liquid phases to achieve preliminary gas-liquid separation. Gas molecules smoothly pass through the micro-narrow exhaust holes 402 into the sealed gas collecting chamber 403, while liquid ammonia is effectively blocked inside the pipe under the action of surface tension, realizing the basic function of exhausting gas without discharging liquid. Gaseous ammonia entering the sealed gas collection chamber 403 undergoes secondary fine separation via a detachable ammonia-repellent membrane 404 at the outlet of the gas collection chamber 403. The ammonia-repellent membrane 404 is a microporous, permeable, liquid-blocking membrane. Its micropores allow selective permeation of gaseous ammonia molecules and effective retention of liquid ammonia molecules at the molecular scale, ensuring that only gaseous ammonia can pass through the membrane 404 to be discharged to an external gas recovery pipeline or tail gas treatment device, while liquid ammonia is completely blocked inside the gas collection chamber 403, eliminating the safety risk of liquid ammonia leakage. Similarly, the liquid outlet exhaust assembly 7 adopts the same structure and working principle as the liquid inlet exhaust assembly 4. It continuously collects and discharges gas released from the liquid outlet side medium due to temperature increases or pressure fluctuations at the top of the liquid outlet test tube 5, ensuring that the medium inside the liquid outlet test tube 5 is in a continuous single-phase liquid flow state. This avoids the adverse effects of gas-liquid two-phase flow on the measurement accuracy of the flow meter 604 and the dynamic response characteristics of the liquid outlet pressure sensor 602, ensuring the accuracy and stability of each detection parameter on the liquid outlet side. The coordinated operation of the inlet and outlet venting components 4 and 7 ensures that the entire closed-loop test pipeline maintains a good gas-liquid separation state during operation, thereby suppressing the interference of gas-containing media on the accuracy of pump performance testing.

[0062] In summary, this invention provides a low-flow-resistance liquid ammonia pump test pipeline and a multi-point integrated testing component. Both the inlet and outlet test pipes employ a straight-through structure with equal diameter, eliminating the additional resistance caused by diameter changes and bends, and avoiding interference from pipeline pressure drop on pump performance testing. Pressure, temperature, cavitation differential pressure, gas content, and vibration sensors are centrally mounted on the inlet integrated mounting plate, while pressure, temperature, flow rate, vibration, and overpressure sensors are centrally mounted on the outlet integrated mounting plate, enabling synchronous acquisition of signals from each measuring point and eliminating timing errors. The inlet and outlet venting components promptly discharge accumulated gas at the top of the pipeline, preventing gas from affecting test accuracy. The entire device has a compact structure, low flow resistance, and high measurement point integration, making it suitable for both factory and type testing scenarios for liquid ammonia pumps.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions described above can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A test pipeline for a low-flow-resistance liquid ammonia pump and an integrated detection component with multiple measuring points, characterized in that, include: The main body of the liquid ammonia pump (1) has an inlet and an outlet; The liquid inlet test tube (2) is connected to the liquid inlet of the liquid ammonia pump body (1) via a ball head ferrule; The liquid outlet test tube (5) is connected to the outlet of the liquid ammonia pump body (1) through a ball head sleeve, and a regulating valve (8) is connected in series to the downstream section of the liquid outlet test tube (5). The liquid inlet test assembly (3) is disposed on the side wall of the liquid inlet test tube (2) and is used to detect the liquid inlet fluid parameters in the liquid inlet test tube (2); The liquid discharge test assembly (6) is disposed on the side wall of the liquid discharge test tube (5) and is used to detect the liquid discharge parameters in the liquid discharge test tube (5); The liquid inlet and exhaust assembly (4) is located at the top of the liquid inlet test tube (2) and is used to collect and exhaust the gas in the liquid inlet side fluid. The liquid discharge venting assembly (7) is located at the top of the liquid discharge test tube (5) and is used to collect and discharge the gas in the liquid discharge side fluid. The controller (9) is electrically connected to the liquid inlet test assembly (3), the liquid outlet test assembly (6), and the regulating valve (8) respectively, and is used to receive detection signals and control the operation of the regulating valve (8); the liquid inlet test tube (2) and the liquid outlet test tube (5) are both straight pipe structures, and the liquid inlet exhaust assembly (4) and the liquid outlet exhaust assembly (7) have the same structure.

2. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 1, characterized in that, The liquid inlet test assembly (3) includes a liquid inlet integrated mounting plate (301) fixedly disposed on the outer wall of the liquid inlet test tube (2). A liquid inlet pressure sensor (302) is mounted on the liquid inlet integrated mounting plate (301) and the liquid inlet pressure sensor (302) is used to detect the liquid inlet pressure. A plurality of mounting holes (307) are opened on the tube wall of the liquid inlet test tube (2). A rubber sealing gasket is provided in each mounting hole (307). The rubber sealing gasket is sandwiched between the hole wall of the mounting hole (307) and the outer wall of the corresponding detection element.

3. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 2, characterized in that, The liquid inlet integrated mounting plate (301) is also equipped with a liquid inlet temperature sensor (303) and a cavitation differential pressure transmitter (304). The liquid inlet temperature sensor (303) is used to detect the liquid inlet temperature, and the cavitation differential pressure transmitter (304) is used to detect the cavitation differential pressure on the liquid inlet side. The detection ends of the liquid inlet pressure sensor (302), the liquid inlet temperature sensor (303), and the cavitation differential pressure transmitter (304) all pass through the liquid inlet integrated mounting plate (301) and extend into the interior of the liquid inlet test tube (2), and the end face of each detection end is flush with the inner wall of the liquid inlet test tube (2).

4. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 3, characterized in that, The liquid inlet integrated mounting plate (301) is also equipped with a trace gas content detector (305) and a liquid inlet vibration sensor (306). The trace gas content detector (305) is used to detect the trace gas content in the liquid inlet fluid, and the liquid inlet vibration sensor (306) is used to detect the vibration parameters of the liquid inlet test tube (2). The detection probe of the trace gas content detector (305) passes through the liquid inlet integrated mounting plate (301) and the corresponding mounting hole (307) and extends into the flow channel of the liquid inlet test tube (2). The detection probe of the liquid inlet vibration sensor (306) passes through the liquid inlet integrated mounting plate (301) and the corresponding mounting hole (307) and extends into the flow channel of the liquid inlet test tube (2).

5. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 1, characterized in that, The liquid inlet and exhaust assembly (4) includes an arc-shaped gas collection groove (401) continuously opened along the top of the inner wall of the liquid inlet test tube (2), the arc-shaped gas collection groove (401) is used to collect gas in the liquid inlet side fluid; multiple narrow exhaust holes (402) are provided through the arc-shaped gas collection groove (401) and the outer wall of the liquid inlet test tube (2); a sealed gas collection chamber (403) is fixedly provided on the top of the outer wall of the liquid inlet test tube (2), and each of the narrow exhaust holes (402) is connected to the inner cavity of the gas collection chamber (403); an ammonia-repellent membrane (404) is detachably installed at the gas outlet end of the gas collection chamber (403), the ammonia-repellent membrane (404) is a microporous gas-permeable liquid-blocking membrane, used to intercept liquid ammonia and allow gaseous ammonia to pass through.

6. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 1, characterized in that, The liquid discharge test assembly (6) includes a liquid discharge integrated mounting plate (601) fixedly disposed on the outer wall of the liquid discharge test tube (5). The liquid discharge integrated mounting plate (601) is equipped with a liquid discharge pressure sensor (602) and a liquid discharge temperature sensor (603). The liquid discharge pressure sensor (602) is used to detect the liquid discharge pressure, and the liquid discharge temperature sensor (603) is used to detect the liquid discharge temperature. The detection ends of the liquid discharge pressure sensor (602) and the liquid discharge temperature sensor (603) pass through the liquid discharge integrated mounting plate (601) and extend into the interior of the liquid discharge test tube (5), and the end face of each detection end is flush with the inner wall of the liquid discharge test tube (5).

7. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 6, characterized in that, The liquid outlet integrated mounting plate (601) is also equipped with a flow meter (604), a liquid outlet vibration sensor (605), and an overpressure monitoring transmitter (606). The flow meter (604) is used to detect the liquid outlet flow rate. The liquid outlet vibration sensor (605) is used to detect the vibration parameters of the liquid outlet test tube (5). The overpressure monitoring transmitter (606) is used to detect the overpressure state on the liquid outlet side. The detection end of the liquid outlet vibration sensor (605) passes through the liquid outlet integrated mounting plate (601) and extends into the interior of the liquid outlet test tube (5). The detection end of the overpressure monitoring transmitter (606) passes through the liquid outlet integrated mounting plate (601) and extends into the interior of the liquid outlet test tube (5).

8. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 1, characterized in that, The valve stem of the regulating valve (8) is equipped with an opening displacement sensor. The opening displacement sensor is fixedly connected to the valve stem of the regulating valve (8) and electrically connected to the controller (9) to transmit the displacement signal of the valve stem to the controller (9).

9. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 1, characterized in that, The controller (9) is a programmable logic controller or an embedded microcontroller. The signal input terminal of the controller (9) is electrically connected to the inlet pressure sensor (302), the inlet temperature sensor (303), the cavitation differential pressure transmitter (304), the trace gas detector (305), the inlet vibration sensor (306), the outlet pressure sensor (602), the outlet temperature sensor (603), the flow meter (604), the outlet vibration sensor (605), the overpressure monitoring transmitter (606), and the opening displacement sensor, respectively. The control output terminal of the controller (9) is electrically connected to the actuator of the regulating valve (8).

10. The low flow resistance liquid ammonia pump test pipeline and multi-point integrated detection component according to claim 9, characterized in that: The controller (9) has a built-in data acquisition module and a comparison and judgment module. The data acquisition module is used to collect the detection signals of each sensor in real time and generate a monitoring dataset. The comparison and judgment module is used to compare the monitoring dataset with a preset threshold range. When any detection signal exceeds the corresponding preset threshold range, the controller (9) outputs an alarm signal to an external alarm device or host computer.

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