Standard Operation Performance Acceptance Test Specification for Four Types of Anti-Corrosion Heating Tubes After Installation and Retrofit

Standard Operation Performance Acceptance Test Specification for Four Types of Anti-Corrosion Heating Tubes After Installation and Retrofit ## Acceptance Test Specification for 316L Stainless Steel Heating Tubes The primary objectives of the core acceptance test After installation or renovation, evaluate the quality of the welding, the uniformity of the wall thickness, the integrity of the passivation film, the heat exchange efficiency, the reliability of the alkali temperature interlock, and the smoothness of the exhaust pipeline. A comprehensive inventory of test items and the standard judgement criteria 1. Raw material and wall thickness test: Perform a comprehensive ultrasonic wall thickness scan of all tube bundles. The wall thickness tolerance must be maintained within ±5%, with no local thinning exceeding 10% of the nominal thickness. Provide the original documents for the raw material spectral test. 2. Weld surface inspection: Visual and magnifying glass examination of all welding seams to ensure that there are no pits, undercuts, cracks, or oxidation blackening. Complete mechanical polishing is performed to ensure a smooth transition between the pipe body and weld. 3. Hydraulic tightness test: Pressurise the system to 1.2 times the design working pressure and maintain the pressure for 30 minutes. No liquid seepage, sweating, or pressure drop are permitted. 4. Film of passivation detection: Utilise a surface potential tester to verify that the passivation film is uniformly covered and that there are no localised bare metal or rust areas on the pipe's outer wall. 5. Heating efficiency performance test: Conduct three consecutive batches of full-load medium heating; the heating power fluctuation must be maintained within ±5%, and there must be no abnormal power surge induced by heat resistance defects. 6. Alkali cleaning interlock linkage test: The system will automatically cut off heating power and trigger an alarm at 60℃ without failure or delay, simulating an over-temperature of alkaline circulation fluid. 7. Test of exhaust function: The exhaust valve discharges gas smoothly, and there is no persistent bubble accumulation at the high point of the tube bundle when the circulating pump is operated at the normal working flow rate. Disposal regulations that are not qualified Tube bundles with unqualified wall thickness, cracked welds, and incomplete passivation film must be returned for revision or replacement. Before formal production access, interlock and exhaust system defects must be fully rectified. ## Acceptance Test Specification for Pure Titanium the acceptance test parameters for heating tubes cores After installation or renovation, verify the purity of the titanium base material, the anti-oxidation effect of the weld, the surface passivation potential, the tightness of the fluoride isolation pipeline, the dissolved oxygen aeration linkage, and the galvanic corrosion isolation structure. A comprehensive inventory of test items and the standard judgement criteria 1. Raw material qualification verification: Conduct sampling component testing to validate that no impurities are mixing with carbon steel; review the Grade 2 pure titanium factory inspection certificate. 2. Inspection of weld appearance: Argon shield welding without overheating discolouration; no scratches, burrs, or residual fluoride release agent on the entire pipe surface. 3. Electrochemical potential test: The tube bundle surface must be scanned in full coverage; the surface potential must be within the qualified standard range, with no localised low-potential etching areas. 4. Tightness test of the fluoride isolation pipeline: The maximum feeding flow is simulated, and the dual interlock valves operate sensitively. There is no cross-leakage between the fluoride pipeline and the fermentation main pipeline. 5. Hydraulic pressure tightness test: Maintain 1.2 times the design pressure for 30 minutes without any seepage or pressure decrease. 6. Aeration linkage performance test: Activate the CIP cleaning cycle; the aeration device will automatically begin to maintain dissolved oxygen levels above 8mg/L, ensuring that oxygen-rich water is circulated uniformly across all pipe surfaces. 7. Inspection of isolation accessories: The contact points between titanium tubes and carbon steel brackets/flanges are entirely covered with integral PTFE sleeves to prevent metal-to-metal contact. Disposal regulations that are not qualified The replacement of titanium tubes with milky white etching traces, unqualified potential values, and exposed metal contact positions is necessary. The reconstruction of the pipeline and a secondary comprehensive test are necessary in the event of a fluoride pipeline interlock failure. ## Quartz Anti-Corrosion Acceptance Test Specification the acceptance test parameters for heating tubes cores Detect the effectiveness of the alkali pipeline mechanical interlock, the temperature rise rate, and the power density limiting control, as well as the sealing tightness, anti-vibration assembly performance, and internal microcracks and bubbles, following the installation or renovation. A comprehensive inventory of test items and the standard judgement criteria 1. Visual inspection of light transmission cracks: 100% visual scanning under strong light; no internal bubbles, penetrating microcracks, thread edge flaking, or surface frosting. 2. Low-pressure water tightness test: The working flow pressure is circulated for 20 minutes, and there is no leakage at the thread sealing joints. 3. Vibration damping assembly test: Continuously operate the circulating pump at the rated flow velocity for four hours; no abnormal swaying of the quartz tube bundle and no friction collision between the pipe body and its fixed supports. 4. Alkali pipeline interlock forced shutdown test: The alkali liquid supply valve will be manually opened to simulate misoperation. The mechanical interlock will immediately cut off the pipeline and trigger a fault alarm, preventing liquid from entering the quartz loop. 5. Temperature rise rate limit test: Begin full-load heating; the actual heating rate must not exceed 0.4℃/min, and the power density must be consistently controlled below 0.6 W/cm². 6. Thermal shock simulation test: Conduct a slow cooling procedure after heating to the working temperature; no new microcracks are produced after conducting multiple temperature cycle tests. Disposal regulations that are not qualified Quartz tubes with concealed microcracks and edge chipping are immediately discarded; however, the shock absorption structure and alkali interlock system must be modified and retested until they are fully compliant. ## Acceptance Test Specification for PFA Coated Heaters The primary objectives of the core acceptance test After installation or renovation, evaluate the coating's integrity, uniformity in thickness, substrate tightness, temperature interlock protection, delayed cooling program linkage, and anti-abrasion filtering effect. A comprehensive inventory of test items and the standard judgement criteria 1. Coating comprehensive visual scanning test: The entire surface is free of pinholes, penetrating scratches, blisters, peeling, or uneven coating thickness; new finished products are free of yellow ageing discolouration. 2. Coating thickness sampling test: Multiple sites sampling on the pipe body and sealing ends; the thickness meets the design standard without a local ultra-thin area that exposes the substrate. 3. Hydraulic tightness test: Maintain 1.2 times the design pressure for 30 minutes; no liquid seepage from the carbon steel substrate under the coating. 4. Coating adhesion test: A sampling peel test that does not involve the separation of a significant area of the coating from the steel substrate. 5. Over-temperature power-off interlock test: The heating circuit will be automatically disconnected for protection without delay when the continuous medium temperature exceeds 95℃. 6. Post-cleaning slow cooling linkage test: The high-temperature CIP cycle must be completed; the system will automatically execute the 40-minute slow cooling program and cannot be bypassed manually. 7. Solid particle filtering test for pipelines: The front filter effectively intercepts hard impurities without coating scratch risks in input liquid containing standard abrasive particles. Disposal regulations that are not qualified Before acceptance, heaters with pinholes, penetrating scratches, and unqualified adhesion must be replaced. Temperature interlock and slow cooling program defects must be debugged and rectified in their entirety. ## Specifications for Universal Acceptance Management in Installation and Retrofit Projects 1. Acceptance batch division rule: Group test according to single tank heating tube bundle; all test items within the same group must meet the standard simultaneously to successfully complete overall acceptance. Partial qualified single items are not permitted to be signed off separately. 2. Requirement for submitting test records: Record data and take photos of each test link. Bind all inspection reports, test curves, and defect rectification records into the equipment full-life-cycle file as permanent audit vouchers. 3. Third-party re-inspection trigger condition: If the standard is not met twice after rectification, introduce a professional third-party testing institution for independent re-inspection. This includes key core indicators such as wall thickness, coating integrity, and titanium surface potential if they do not meet the standard. 4. Production trial run confirmation clause: The final pass condition of overall acceptance is the completion of a continuous full-load production trial run for two batches after passing static acceptance tests. The trial run must not experience any abnormal alarms, efficiency attenuation, or equipment damage. 5. Restrictions on acceptance signature authority: Operators who lack testing authority are prohibited from verifying acceptance results; only professional equipment engineers with the appropriate material heating tube training qualification are permitted to sign acceptance documents. ## Executive Summary Core testing items that address the inherent quality risks of four varieties of heating tubes are differentiated in the acceptance test specifications. The following are the mandatory inspection contents for titanium tube testing: material purity, surface potential, and fluoride isolation pipeline. Quartz acceptance prioritises light transmission crack screening and alkali liquid interlock safety test. PFA coating heaters are tested for coating integrity, adhesion, and high-temperature protection linkage. Stainless steel acceptance is centred on welding, wall thickness, and alkali interlock performance. After the installation of new equipment or the renovation of old equipment, the strict implementation of standardised full-item acceptance tests can eliminate hidden quality defects in heating tubes before formal production startup. This approach also prevents frequent failures and quality pollution accidents in subsequent operation, and ensures that the heating system aligns with the design performance indicators for long-term stable operation.