Mobile system for monitoring leaks in gland of gate valve with main line for supplying signal gas medium

Abstract

FIELD: pipeline industry.SUBSTANCE: invention relates to sealing and purging of shut-off valves, specifically to mobile systems for monitoring leaks in gland seals of gate valves for pipelines transporting hazardous process fluids. The mobile system for monitoring leaks in the gland of a gate valve comprises a pipeline for connection to the gland, a main line for supplying a signal gas medium, connected to an autonomous container with nitrogen, equipped with a gas level indicator, and pressure gauges for pressure monitoring. The system is equipped with a fine filter, a shut-off valve, a pressure regulator, a flow limiter and a shut-off valve located sequentially after it on the main line. Two hydraulic-type dampers are installed on the system, located on the corresponding parallel monitoring branches, the first of which is connected to the section of the main line between the pressure regulator and the flow limiter, and the second to the section between the valve and the pipeline. Each of said monitoring branches contains a shut-off valve, a pressure relief valve installed at the damper inlet, and a pressure gauge connected to the damper outlet. The valve is located between the connection points of said branches.EFFECT: elimination of dependence on centralised nitrogen due to a compact autonomous container; reduced weight and dimensions of the system; reduced pressure measurement error due to hydraulic-type dampers; reduced time for diagnosing the condition of seals without stopping equipment; increased service life of sealing groups due to the use of fine filters and dampers stabilising pressure.1 cl, 2 dwg

Description

[0001] The invention relates to sealing and purging shut-off valves, specifically to mobile systems for monitoring leaks in gland seals of gate valves for pipelines transporting hazardous process media.

[0002] A similar design, patented by CA 2003760 A1, comprises a stuffing box with primary sealing assemblies, an intermediate sealant injection unit, and a bleed ring for supplying purge gas in the event of an internal seal failure. Disadvantages: the lack of dampers, filters, and shut-off valves for maintenance, which reduces operational safety and reliability.

[0003] The closest analog (prototype) is a system for purging a shut-off valve with a liquid purge medium, as described in US Patent No. 11852258 B2. It includes a line supplying a gas purge medium (nitrogen) at a pressure 20-30% higher than the operating pressure to detect leaks and prevent process fluid leakage from the pipeline. The system replaces gas purging with a liquid purge medium from a distillation column, such as hydrocarbons or oils. This reduces cavitation in the pressure line as the process fluid passes through the valve.

[0004] The disadvantages of the prototype are:

[0005] 1. High leakage control error due to lack of pressure pulsation damping.

[0006] 2. Limited mobility due to dependence on a stationary nitrogen station.

[0007] 3. Impossibility of diagnosing seals without stopping the technological process.

[0008] 4. Reduction in the service life of sealing groups due to penetration of abrasive particles.

[0009] The technical problems solved by the proposed invention are:

[0010] 1. Ensuring the mobility of the leak control system.

[0011] 2. Improving the accuracy of pressure measurement under pulsation conditions.

[0012] 3. Creating the possibility of prompt diagnostics of seals without stopping the equipment.

[0013] Technical effects of the invention:

[0014] 1. Eliminate dependence on centralized nitrogen with independent tank (14).

[0015] 2. Reduction of the system weight and dimensions due to the autonomous tank (14) with nitrogen, replacing a stationary nitrogen station with piping.

[0016] 3. Reducing the error of pressure measurements due to dampers (5).

[0017] 4. Reducing the time for diagnosing seal conditions without stopping equipment.

[0018] 5. Increased service life of sealing groups due to the use of fine filters (12) that block abrasive particles, and hydraulic dampers (5) that stabilize pressure, eliminating seal erosion from hydraulic shock.

[0019] 6. Elimination of emergency ruptures of dampers when pressure is released.

[0020] The overall technical result is a significant improvement in the operational and service life characteristics of the gland seal and, accordingly, the characteristics of the gate valve.

[0021] The invention has the following essential features in common with the prototype: a leak monitoring system in a gate valve gland, comprising a pipeline (1) for connecting to the gland; a line (2) for supplying a signal gas medium; a container (14) with nitrogen; pressure gauges (6, 9) for monitoring pressure.

[0022] The technical result is achieved by a mobile system for monitoring leaks in a gate valve packing gland with a line for supplying a signal gas medium, containing a pipeline (1) for connecting to the packing gland, a line (2) for supplying a signal gas medium, connected to an autonomous tank (14) with nitrogen, equipped with a gas level indicator (13), and pressure gauges (6, 9) for monitoring pressure, differing from the prototype in that a fine filter (12) is introduced, installed after the gas level indicator (13), a shut-off valve (11), a pressure regulator (10), a flow limiter (8) and a shut-off valve (7) sequentially located on the line (2) starting from the fine filter (12), as well as two hydraulic dampers (5) located on the corresponding parallel control branches, the first of which is connected to the section of the line (2) between the pressure regulator (10) and the flow limiter (8), and the second one - to the section between the valve (7) and the pipeline (1),each of the said control branches contains a shut-off valve (3), a pressure relief valve (4) installed at the inlet of the damper (5), and a pressure gauge (6 or 9) connected to the outlet of the damper, wherein the valve (7) is located between the connection points of the said branches.

[0023] Integrating additional equipment improves pressure control accuracy and seal reliability. Line (2) supplies nitrogen at a pressure 20-30% higher than the operating pressure, ensuring prompt leak detection. Pressure regulation is accomplished using shut-off valves, allowing for a temporary pressure increase of 50% for testing.

[0024] Fig. 1 shows the main view of a gate valve with a mobile leakage control system connected to it;

[0025] Fig. 2 shows a diagram of the pipeline for supplying the signal gas medium.

[0026] The figures show the following positions: 1 - pipeline connecting to the gate valve stuffing box; 2 - signal gas medium (nitrogen) supply line; 3, 4, 7, 11 - shut-off valve; 5 - dampers; 6, 9 - pressure gauge; 8 - flow limiter; 10 - pressure regulator; 12 - filter; 13 - gas level indicator; 14 - nitrogen tank.

[0027] The mobile leak detection system comprises a pipeline (1) for connection to the gate valve gland, connected to a line (2) for supplying a signal gas medium (nitrogen) to the gland. An autonomous tank (14) with nitrogen is equipped with a gas level indicator (13) and is connected to the line (2) through a fine filter (12) (10 μm) that blocks abrasive particles. The following are installed in series on the line (2): a shut-off valve (11) after the filter (12), a pressure regulator (10) for controlling the nitrogen supply, a flow limiter (8), and a shut-off valve (7) forming a test pressure circuit. The first hydraulic damper (5) is connected to the section of the line (2) between the pressure regulator (10) and the flow limiter (8). The second hydraulic damper (5) is installed between the valve (7) and the pipeline (1). These dampers are designed to dampen pressure pulsations and operate on parallel control lines. Each of these lines includes:

[0028] - Hydraulic type damper (5);

[0029] - Pressure relief valve (4) installed at the damper inlet;

[0030] - Pressure gauge (6, 9) connected to the damper outlet;

[0031] - Shut-off valve (3) regulating the supply of nitrogen to the branch.

[0032] To ensure mobility and structural integrity, all listed components of the device are mounted on a common frame (platform) (not shown in the figure), made, for example, of a steel profile. The layout of the elements on the frame is rational and ensures compactness, ease of transportation, and functional coherence.

[0033] During installation, the damper branches must be positioned strictly horizontally to eliminate measurement errors caused by pressure gradients in the gas environment. The pressure gauge (6) indicates the nitrogen pressure in the tank, while the pressure gauge (9) indicates the pressure inside the sealed cavity of the gland. The shut-off valve (7) is located on the line (2) between the connection points of these parallel control branches.

[0034] The system operates as follows: nitrogen from a separate tank (14) passes through a filter (12), where it is cleaned of abrasive particles, and then enters the line (2). The pressure regulator (10) sets the excess nitrogen supply pressure at 20-30% above the working pressure in the seal, and the flow restrictor (8) stabilizes the gas flow. In normal operation, nitrogen is supplied to the sealed cavity of the seal (not shown in the figure) through the pipeline (1), creating excess pressure of the signal gas environment to monitor the tightness.

[0035] Pressure pulsations are dampened by hydraulic dampers (5) installed on parallel branches: the first damper (5) monitors flow parameters downstream of the regulator (10), while the second monitors the pressure in the gland area upstream of the pipeline (1). Pressure gauges (6, 9) continuously display pressure, and a drop in pressure on gauge (6) indicates a leak through the sealed cavity of the gland (e.g., through its sealing groups). If such a leak occurs, nitrogen is purged out.

[0036] To test the seals (gland seal groups), the pressure is temporarily increased by 50% above the working pressure using the regulator (10) and the limiter (8). The shut-off valve (7) is closed, isolating the test pressure circuit from the source (14) and forming a closed volume, which includes a section of the line (2) after the valve (7), the second damper (5), the pipeline (1) and the sealed cavity of the gland. The difference in the rate of pressure drop is recorded by the pressure gauge (6) and is caused by different hydraulic resistance of the leakage paths: when the shut-off valve (3) is open, the pressure in the line (2) before the valve (7) is equalized with the pressure in the closed volume through the first damper (5). If within 5 minutes the pressure on the pressure gauge (6) drops to the working level, a leak through a seal with high hydraulic resistance is recorded; If it drops to zero within 30 seconds, this indicates a leak through a seal with low hydraulic resistance.Upon completion of the test, excess pressure is released through valves (4) installed at the damper inlets (5). Valves (3) allow the branches to be isolated for servicing or replacing dampers and pressure gauges without shutting down the system.

[0037] Thus, the declared system has significant differences from the prototype and achieves the declared technical results due to the use of:

[0038] 1. Transportable autonomous nitrogen cylinder (14), allowing to abandon dependence on a centralized nitrogen supply system for purging.

[0039] 2. Dampers (5) in front of the pressure gauges (6, 9), used to stabilize pressure readings, dampen pulsations and pressure surges caused by the operation of the regulator (10), which reduces measurement errors and improves the overall safety of the system.

[0040] 3. Configurations of shut-off valves (3, 7, 11) for prompt maintenance and repair of system components and performing operational checks of gland seals without stopping the system.

[0041] 4. Filter (12), providing additional protection, increasing the service life of seals by blocking the ingress of solid particles, and the safety of system operation.

[0042] 5. Parallel branches allowing calibration of the pressure gauge (9) at the outlet of the tank (14) without interrupting the control of the gland (pressure gauge (6)).

[0043] All claimed technical results of the invention are achieved solely through the combination of features stated in the claims. Experimental studies confirm that the combined use of an autonomous nitrogen tank, a fine filter, hydraulic dampers, a pressure regulator, a flow restrictor, and parallel control lines provides a comprehensive solution to the stated technical problems. Achieving the stated technical effects and the overall technical result is due to the interconnected operation of all system elements as a whole, as confirmed by tests conducted under conditions corresponding to actual operating parameters. Consequently, the combination of features set forth in the claims is sufficient to achieve all the stated technical effects and the overall technical result, which meets the patentability requirements for industrial applicability.

Claims

A mobile system for monitoring leaks in a gate valve gland with a pipeline for supplying a signal gas medium, comprising a pipeline for connecting to the gland, a pipeline for supplying a signal gas medium, connected to an autonomous tank with nitrogen, equipped with a gas level indicator, and pressure gauges for monitoring the pressure, characterized in that a fine filter is introduced, installed after the gas level indicator, a shut-off valve, a pressure regulator, a flow limiter and a shut-off valve, arranged in series after the filter on the pipeline, as well as two hydraulic dampers, located on the corresponding parallel branches of the control: the first damper is connected to the section of the pipeline between the pressure regulator and the flow limiter, and the second damper is connected to the section between the valve and the pipeline;each of the said control branches contains a shut-off valve, a pressure relief valve installed at the inlet of the damper, and a pressure gauge connected to the outlet of the damper, with the valve located between the connection points of the said branches.

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