As a key fluid control component in industrial automation control systems, angle seat valves' performance directly impacts the stability and safety of production processes. To ensure reliable operation under complex operating conditions, a systematic inspection process is required to comprehensively evaluate their functionality, sealing, and durability. The following details the standard inspection process for angle seat valves, from inspection preparation, key items, to result evaluation.
Pre-Inspection Preparation
Before inspection, the technical parameters of the angle seat valve (such as nominal diameter, pressure rating, media type, and temperature range) must be clearly defined, and a testing plan must be developed in accordance with relevant standards (such as ISO 5208 and GB/T 13927). First, inspect the valve body for casting defects (such as pinholes or cracks), scratches on the sealing surface, or loose components. Secondly, ensure that the testing environment temperature (typically 5-40°C) and humidity (≤85% RH) meet requirements. Prepare tools such as a high-precision pressure gauge (with a range covering 1.5 times the operating pressure), a flow meter, a leak detector (such as a helium mass spectrometer or bubble detector), a drive air source (for pneumatic valves), and a power supply (for electric valves). For new valves, perform a visual and dimensional review; for repaired valves, focus on verifying the compatibility of replacement components.
Core Inspection Items and Methods
(I) Appearance and Dimensional Inspection
Using a combination of visual inspection and tools such as calipers and micrometers, inspect key components such as the valve body, bonnet, and valve core for surface roughness (Ra ≤ 3.2μm), thread integrity, and sealing surface flatness (deviation ≤ 0.05mm). Ensure the absence of cracks, corrosion pits, or deformation, thread stripping, and sealing surface damage-these defects could lead to leakage or sticking. (II) Sealing Performance Test
Sealing performance is a core performance indicator for angle seat valves. It is divided into two types of tests: internal leakage (leakage between the valve seat and valve core) and external leakage (leakage at the connection):
1.Internal Leakage Test: Close the valve and drive it to the fully closed position through the air inlet (pneumatic valve) or power supply (electric valve). Apply 1.1 times the nominal pressure (for gaseous media) or 1.5 times the nominal pressure (for liquid media) to the inlet. Maintain pressure for 5-10 minutes. Apply a leak detector (such as soapy water) to the valve seat seal or connecting flange to observe for the formation of continuous bubbles. Alternatively, connect a leak detector and ensure a leakage rate of ≤0.1% of the rated flow rate (the specific value depends on the operating conditions).
2.External Leakage Test: Apply 0.6 MPa compressed air (or nitrogen) to all connection interfaces (such as threads, flanges, and welded ends) for 3 minutes. Check for visible bubbles or pressure drop (pressure drop ≤5% of the initial value). For valves operating under high-temperature conditions, the sealability must also be retested in a hot state (operating temperature ±10°C) to verify the sealing reliability after thermal expansion of the material.
(III) Performance Testing
For pneumatic or electric angle seat valves, simulate the switching operation under actual operating conditions:
•Pneumatic valves: Connect an air source (0.4-0.7MPa clean compressed air) and control the switch via a solenoid valve. Record the time from fully open to fully closed (usually ≤2 seconds) and the stability of the operation, observing for any sticking, abnormal noise, or non-positioning. Repeat the operation at least 10 times to verify wear resistance and response consistency.
•Electric valves: Connect a rated power supply (AC/DC 24V/220V) and send a switch signal through the controller to test the valve opening and closing time (deviation from design parameters ≤10%) and whether the torque output meets the valve core actuation requirements. Check the accuracy of the limit switch triggering (fully open/closed position deviation ≤1°). (IV) Pressure Resistance Test
To verify the valve body's pressure resistance, place the valve in the closed or fully open position (according to standard requirements) and apply 1.5 times the nominal pressure (for gas) or 2 times the nominal pressure (for liquid) internally. Maintain pressure for 10-15 minutes and inspect the valve body for plastic deformation, weld cracking, or leaks at joints. This test is only applicable to factory inspection of new valves; it is generally not performed on repaired valves.
Test Result Evaluation and Processing
After all test items are completed, the data must be summarized and compared with the technical specifications. If the sealing, actuation time, and pressure resistance meet the standards (e.g., leakage rate ≤ allowable value, actuation time deviation within the range), the valve is deemed qualified, a qualified label is affixed, and the test parameters are recorded. If any item fails to meet the standards (e.g., excessive internal leakage, stuck actuation, or pressure leakage), the item must be marked as unqualified, the cause analyzed (e.g., worn sealing surface, drive mechanism failure, or valve body defect), and targeted repairs (e.g., grinding the sealing surface, replacing the seal ring, or repairing the valve body) are performed before re-inspection. The valve can be put into service only after all indicators meet the standards. Conclusion
A standardized angle seat valve inspection process is fundamental to ensuring long-term, stable operation. Through systematic visual inspection, leak-proofness verification, performance testing, and pressure resistance assessment, potential hazards can be accurately identified, providing reliable assurance for fluid control in industrial production. In actual operation, inspectors must strictly adhere to standard procedures and adjust parameters based on specific operating conditions to ensure that every angle seat valve meets the core requirements of "zero leakage and high reliability."