Pengujian bukti minangka bagean integral saka pangopènan integritas safety sistem instrumented safety (SIS) lan sistem sing gegandhengan karo safety (contone, weker kritis, sistem geni & gas, sistem interlock instrumen, lsp.). Tes bukti minangka tes periodik kanggo ndeteksi kegagalan sing mbebayani, nguji fungsi sing gegandhengan karo safety (contone, reset, bypass, weker, diagnostik, mati manual, lsp.), lan mesthekake sistem kasebut cocog karo standar perusahaan lan eksternal. Asil tes bukti uga minangka ukuran efektifitas program integritas mekanik SIS lan keandalan sistem ing lapangan.
Prosedur tes bukti kalebu langkah-langkah tes saka entuk ijin, nggawe kabar lan njupuk sistem metu saka layanan kanggo tes kanggo mesthekake tes lengkap, nyathet tes bukti lan asile, nempatake sistem maneh ing layanan, lan ngevaluasi asil tes saiki lan bukti sadurunge asil tes.
ANSI/ISA/IEC 61511-1, Klausa 16, nyakup tes bukti SIS. Laporan teknis ISA TR84.00.03 - "Integritas Mekanik Sistem Instrumen Keamanan (SIS)," nyakup tes bukti lan saiki ana ing revisi kanthi versi anyar sing bakal ditindakake. Laporan teknis ISA TR96.05.02 - "In-situ Proof Testing of Automated Valves" saiki lagi dikembangake.
Laporan HSE UK CRR 428/2002 - "Prinsip kanggo uji coba bukti sistem instrumen safety ing industri kimia" nyedhiyakake informasi babagan uji coba bukti lan apa sing ditindakake perusahaan ing Inggris.
Prosedur tes bukti adhedhasar analisis mode kegagalan mbebayani sing dikenal kanggo saben komponen ing jalur trip safety instrumented function (SIF), fungsi SIF minangka sistem, lan carane (lan yen) kanggo nguji kegagalan mbebayani. modus. Pangembangan prosedur kudu diwiwiti ing tahap desain SIF kanthi desain sistem, pilihan komponen, lan nemtokake kapan lan cara uji coba. Instrumen SIS duwe macem-macem tingkat kesulitan testing bukti sing kudu dianggep ing desain SIF, operasi lan pangopènan. Contone, meter orifice lan pemancar tekanan luwih gampang diuji tinimbang meter aliran massa Coriolis, meter mag utawa sensor tingkat radar liwat udara. Desain aplikasi lan katup uga bisa mengaruhi komprehensif tes bukti katup kanggo mesthekake yen kegagalan sing mbebayani lan incipient amarga degradasi, plugging utawa gagal gumantung wektu ora nyebabake kegagalan kritis ing interval tes sing dipilih.
Nalika prosedur tes bukti biasane dikembangake sajrone fase teknik SIF, prosedur kasebut uga kudu dideleng dening Otoritas Teknis, Operasi SIS lan teknisi instrumen sing bakal nindakake tes kasebut. Analisa keamanan kerja (JSA) uga kudu ditindakake. Penting kanggo njaluk tuku pabrik babagan tes apa sing bakal ditindakake lan kapan, lan kelayakan fisik lan safety. Contone, ora ana gunane kanggo nemtokake tes stroke parsial nalika grup Operasi ora setuju kanggo nindakake. Disaranake uga supaya prosedur tes bukti dideleng dening pakar subyek (SME) independen. Pengujian khas sing dibutuhake kanggo tes bukti fungsi lengkap digambarake ing Gambar 1.
Keperluan tes bukti fungsi lengkap Gambar 1: Spesifikasi tes bukti fungsi lengkap kanggo fungsi instrumen safety (SIF) lan sistem instrumen safety (SIS) kudu ngeja utawa ngrujuk langkah-langkah kanthi urutan saka persiapan tes lan prosedur tes nganti kabar lan dokumentasi .
Gambar 1: Spesifikasi tes bukti fungsi lengkap kanggo safety instrumented function (SIF) lan safety instrumented system (SIS) kudu ngeja utawa ngrujuk langkah-langkah kanthi urutan saka persiapan tes lan prosedur tes nganti kabar lan dokumentasi.
Pengujian bukti minangka tumindak pangopènan sing direncanakake sing kudu ditindakake dening personel sing kompeten sing dilatih ing pengujian SIS, prosedur bukti, lan loop SIS sing bakal dites. Mesthine ana langkah-langkah prosedur sadurunge nindakake tes bukti awal, lan umpan balik menyang Otoritas Teknis SIS situs kanggo perbaikan utawa koreksi.
Ana rong mode gagal utama (aman utawa mbebayani), sing dipérang dadi patang mode-mbebayani ora dideteksi, mbebayani dideteksi (dening diagnostik), aman ora dideteksi lan aman dideteksi. Istilah-istilah kegagalan sing ora dideteksi sing mbebayani lan mbebayani digunakake ing artikel iki.
Ing uji coba bukti SIF, kita utamane kasengsem ing mode kegagalan sing ora dideteksi mbebayani, nanging yen ana diagnostik pangguna sing ndeteksi kegagalan sing mbebayani, diagnostik kasebut kudu diuji bukti. Elinga yen ora kaya diagnostik pangguna, diagnostik internal piranti biasane ora bisa divalidasi minangka fungsional dening pangguna, lan iki bisa mengaruhi filosofi tes bukti. Nalika kridit diagnostik dijupuk ing petungan SIL, weker diagnostik (contone, weker sing ora ana jarak) kudu diuji minangka bagean saka tes bukti.
Mode gagal bisa dipérang manèh dadi sing dites sajrone tes bukti, sing ora dites, lan kegagalan sing diwiwiti utawa kegagalan sing gumantung karo wektu. Sawetara mode Gagal mbebayani bisa uga ora langsung dites kanggo macem-macem alasan (contone, kangelan, engineering utawa kaputusan operasional, nggatekke, incompetence, omission utawa komisi kesalahan sistematis, kemungkinan cilik kedadeyan, etc.). Yen ana mode kegagalan sing dikenal sing ora bakal dites, ganti rugi kudu ditindakake ing desain piranti, prosedur tes, panggantos piranti utawa mbangun maneh, lan / utawa tes inferensi kudu ditindakake kanggo nyilikake efek ing integritas SIF sing ora dites.
Gagal wiwitan minangka kahanan utawa kahanan sing ngremehake, saengga kegagalan kritis lan mbebayani bisa ditindakake yen tumindak koreksi ora ditindakake kanthi pas wektune. Biasane dideteksi kanthi mbandhingake kinerja karo tes bukti pathokan anyar utawa awal (contone, tandha katup utawa wektu nanggepi katup) utawa kanthi inspeksi (contone port proses sing dipasang). Gagal wiwitan biasane gumantung ing wektu-suwene piranti utawa perakitan digunakake, saya suwe saya rusak; kahanan sing nggampangake Gagal acak dadi liyane kamungkinan, proses port plugging utawa sensor buildup liwat wektu, urip migunani wis entek, etc.. Mulane, maneh interval test bukti, liyane kamungkinan Gagal incipient utawa wektu-gumantung. Sembarang proteksi marang kegagalan sing diwiwiti uga kudu diuji bukti (purging port, tracing panas, lsp.).
Prosedur kudu ditulis kanggo tes bukti kanggo kegagalan sing mbebayani (ora dideteksi). Mode kegagalan lan analisis efek (FMEA) utawa mode kegagalan, efek lan teknik analisis diagnostik (FMEDA) bisa mbantu ngenali kegagalan sing ora dideteksi mbebayani, lan ing ngendi jangkoan uji coba kudu ditingkatake.
Akeh prosedur test bukti ditulis pengalaman adhedhasar lan Cithakan saka prosedur ana. Prosedur anyar lan SIF sing luwih rumit mbutuhake pendekatan sing luwih direkayasa nggunakake FMEA / FMEDA kanggo nganalisa kegagalan sing mbebayani, nemtokake cara prosedur tes bakal utawa ora bakal nyoba kanggo kegagalan kasebut, lan jangkoan tes kasebut. Diagram blok analisis mode kegagalan tingkat makro kanggo sensor ditampilake ing Figure 2. FMEA biasane mung kudu ditindakake sapisan kanggo jinis piranti tartamtu lan digunakake maneh kanggo piranti sing padha kanthi nimbang layanan proses, instalasi lan kemampuan testing situs. .
Analisis kegagalan tingkat makro Gambar 2: Diagram blok analisis mode kegagalan level makro iki kanggo sensor lan pemancar tekanan (PT) nuduhake fungsi utama sing biasane bakal dipérang dadi pirang-pirang analisis kegagalan mikro kanggo nemtokake kanthi lengkap kegagalan potensial sing bakal ditangani. ing tes fungsi.
Gambar 2: Diagram blok analisis mode kegagalan level makro iki kanggo sensor lan pemancar tekanan (PT) nuduhake fungsi utama sing biasane bakal dipecah dadi pirang-pirang analisa kegagalan mikro kanggo nemtokake kegagalan potensial sing bakal ditindakake ing tes fungsi.
Persentase kegagalan sing dikenal, mbebayani, ora dideteksi sing diuji bukti diarani jangkoan uji bukti (PTC). PTC umume digunakake ing petungan SIL kanggo "ngijoli" kanggo Gagal kanggo nyoba luwih lengkap SIF. Wong duwe kapercayan sing salah amarga wis nganggep kekurangan jangkoan tes ing petungan SIL, dheweke wis ngrancang SIF sing bisa dipercaya. Kasunyatan sing prasaja, yen jangkoan tes sampeyan 75%, lan yen sampeyan ngetung angka kasebut ing petungan SIL lan nyoba perkara sing sampeyan wis nyoba luwih kerep, 25% saka kegagalan mbebayani isih bisa kedadeyan sacara statistik. Aku mesthi ora pengin dadi ing 25%.
Laporan persetujuan FMEDA lan manual safety kanggo piranti biasane nyedhiyakake prosedur tes bukti minimal lan jangkoan tes bukti. Iki mung menehi pandhuan, ora kabeh langkah tes sing dibutuhake kanggo prosedur tes bukti lengkap. Jinis analisis kegagalan liyane, kayata analisis wit fault lan pangopènan pusat linuwih, uga digunakake kanggo nganalisa kegagalan sing mbebayani.
Tes bukti bisa dipérang dadi tes fungsional lengkap (end-to-end) utawa tes fungsional parsial (Gambar 3). Pengujian fungsi parsial biasane ditindakake nalika komponen SIF duwe interval tes sing beda-beda ing petungan SIL sing ora cocog karo shutdowns utawa turnarounds sing direncanakake. Penting yen prosedur uji bukti fungsional parsial tumpang tindih supaya bisa nyoba kabeh fungsi safety SIF. Kanthi tes fungsi parsial, isih disaranake supaya SIF duwe tes bukti pungkasan nganti pungkasan, lan sing sabanjure sajrone giliran.
Tes bukti sebagean kudu ditambahake Gambar 3: Tes bukti sebagean gabungan (ngisor) kudu nutupi kabeh fungsi tes bukti fungsional lengkap (ndhuwur).
Gambar 3: Tes bukti sebagean gabungan (ngisor) kudu nyakup kabeh fungsi tes bukti fungsional lengkap (ndhuwur).
Tes bukti sebagean mung nguji persentase mode kegagalan piranti. Conto umum yaiku tes katup stroke parsial, ing ngendi katup dipindhah kanthi jumlah cilik (10-20%) kanggo verifikasi manawa ora macet. Iki nduweni jangkoan tes bukti sing luwih murah tinimbang tes bukti ing interval tes utama.
Prosedur tes bukti bisa beda-beda ing kerumitan karo kerumitan SIF lan filosofi prosedur tes perusahaan. Sawetara perusahaan nulis prosedur tes langkah-langkah kanthi rinci, dene liyane duwe prosedur sing cukup ringkes. Referensi kanggo prosedur liyane, kayata kalibrasi standar, kadhangkala digunakake kanggo nyuda ukuran prosedur tes bukti lan kanggo njamin konsistensi ing tes. Prosedur tes bukti sing apik kudu menehi katrangan sing cukup kanggo mesthekake yen kabeh tes wis rampung lan didokumentasikake kanthi bener, nanging ora luwih rinci sing nyebabake teknisi pengin ngliwati langkah. Duwe teknisi, sing tanggung jawab kanggo nindakake langkah tes, wiwitan langkah tes sing wis rampung bisa mbantu mesthekake yen tes bakal ditindakake kanthi bener. Ndhaptar tes bukti sing wis rampung dening Supervisor Instrumen lan wakil Operasi uga bakal nandheske pentinge lan njamin tes bukti sing wis rampung kanthi bener.
Umpan balik teknisi kudu tansah diundang kanggo mbantu ningkatake prosedur kasebut. Kasuksesan prosedur tes bukti akehe ana ing tangan teknisi, mula usaha kolaborasi dianjurake banget.
Umume pangujian bukti biasane ditindakake ing off-line sajrone mateni utawa mundur. Ing sawetara kasus, tes bukti bisa uga kudu ditindakake kanthi online nalika mlaku kanggo nyukupi petungan SIL utawa syarat liyane. Pengujian online mbutuhake perencanaan lan koordinasi karo Operasi kanggo ngidini tes bukti bisa ditindakake kanthi aman, tanpa gangguan proses, lan tanpa nyebabake trip palsu. Perlu mung siji trip palsu kanggo nggunakake munggah kabeh attaboys Panjenengan. Sajrone tes jinis iki, nalika SIF ora kasedhiya kanggo nindakake tugas safety, 61511-1, Klausa 11.8.5, nyatakake yen "Langkah-langkah kompensasi sing njamin operasi aman terus bakal diwenehake sesuai karo 11.3 nalika SIS ana. bypass (repair utawa testing). Prosedur manajemen kahanan sing ora normal kudu nganggo prosedur tes bukti kanggo mbantu mesthekake yen ditindakake kanthi bener.
A SIF biasane dipérang dadi telung bagean utama: sensor, solver logika lan unsur pungkasan. Biasane uga ana piranti tambahan sing bisa digandhengake ing saben telung bagean kasebut (contone, penghalang IS, amps trip, relay interposing, solenoida, lsp.) sing uga kudu diuji. Aspek kritis kanggo nguji bukti saben teknologi kasebut bisa ditemokake ing sidebar, "Sensor tes, pemecah logika lan unsur pungkasan" (ing ngisor iki).
Sawetara perkara luwih gampang kanggo bukti tes tinimbang liyane. Akeh teknologi aliran lan level modern lan sawetara sing luwih lawas ana ing kategori sing luwih angel. Iki kalebu flowmeters Coriolis, meter vortex, meter mag, radar liwat-ing-udara, tingkat ultrasonik, lan saklar proses ing-situ, kanggo sawetara jeneng. Untunge, akeh sing saiki duwe diagnostik sing luwih apik sing ngidini tes sing luwih apik.
Kesulitan uji coba piranti kasebut ing lapangan kudu dianggep ing desain SIF. Gampang kanggo teknik milih piranti SIF tanpa mikir babagan apa sing dibutuhake kanggo nguji piranti kasebut, amarga ora bakal dadi wong sing nyoba. Iki uga bener saka testing sebagean-stroke, kang cara umum kanggo nambah SIF rata-rata kemungkinan Gagal ing dikarepake (PFDavg), nanging mengko ing operasi tanduran ora pengin nindakaken, lan kakehan bisa uga ora. Tansah nyedhiyakake pengawasan pabrik babagan teknik SIF babagan uji coba bukti.
Test bukti kudu kalebu pengawasan instalasi lan ndandani SIF minangka perlu kanggo ketemu 61511-1, Klausa 16.3.2. Mesthine ana pamriksan pungkasan kanggo mesthekake yen kabeh wis kancing, lan priksa manawa SIF wis dipasang maneh ing layanan proses.
Nulis lan ngetrapake prosedur tes sing apik minangka langkah penting kanggo njamin integritas SIF sajrone umure. Prosedur tes kudu nyedhiyakake rincian sing cukup kanggo mesthekake yen tes sing dibutuhake ditindakake kanthi konsisten lan aman lan didokumentasikake. Gagal mbebayani sing ora dites dening tes bukti kudu menehi ganti rugi kanggo mesthekake yen integritas safety SIF dijaga kanthi cukup sajrone umure.
Nulis prosedur uji bukti sing apik mbutuhake pendekatan logis kanggo analisis teknik babagan kegagalan potensial sing mbebayani, milih cara, lan nulis langkah-langkah uji bukti sing ana ing kemampuan uji coba pabrik. Ing sadawane dalan, entuk tuku pabrik ing kabeh level kanggo tes, lan nglatih teknisi kanggo nindakake lan nyathet tes bukti uga ngerti pentinge tes kasebut. Tulis instruksi kaya-kaya sampeyan minangka teknisi instrumen sing kudu nindakake pakaryan kasebut, lan urip gumantung saka tes sing bener, amarga padha nindakake.
Testing sensors, logic solvers and final elements A SIF is typically divided up into three main parts, sensors, logic solvers and final elements. There also typically are auxiliary devices that can be associated within each of these three parts (e.g. I.S. barriers, trip amps, interposing relays, solenoids, etc.) that must also be tested.Sensor proof tests: The sensor proof test must ensure that the sensor can sense the process variable over its full range and transmit the proper signal to the SIS logic solver for evaluation. While not inclusive, some of the things to consider in creating the sensor portion of the proof test procedure are given in Table 1. Table 1: Sensor proof test considerations Process ports clean/process interface check, significant buildup noted Internal diagnostics check, run extended diagnostics if available Sensor calibration (5 point) with simulated process input to sensor, verified through to the DCS, drift check Trip point check High/High-High/Low/Low-Low alarms Redundancy, voting degradation Out of range, deviation, diagnostic alarms Bypass and alarms, restrike User diagnostics Transmitter Fail Safe configuration verified Test associated systems (e.g. purge, heat tracing, etc.) and auxiliary components Physical inspection Complete as-found and as-left documentation Logic solver proof test: When full-function proof testing is done, the logic solver’s part in accomplishing the SIF’s safety action and related actions (e.g. alarms, reset, bypasses, user diagnostics, redundancies, HMI, etc.) are tested. Partial or piecemeal function proof tests must accomplish all these tests as part of the individual overlapping proof tests. The logic solver manufacturer should have a recommended proof test procedure in the device safety manual. If not and as a minimum, the logic solver power should be cycled, and the logic solver diagnostic registers, status lights, power supply voltages, communication links and redundancy should be checked. These checks should be done prior to the full-function proof test.Don’t make the assumption that the software is good forever and the logic need not be tested after the initial proof test as undocumented, unauthorized and untested software and hardware changes and software updates can creep into systems over time and must be factored into your overall proof test philosophy. The management of change, maintenance, and revision logs should be reviewed to ensure they are up to date and properly maintained, and if capable, the application program should be compared to the latest backup.Care should also be taken to test all the user logic solver auxiliary and diagnostic functions (e.g. watchdogs, communication links, cybersecurity appliances, etc.).Final element proof test: Most final elements are valves, however, rotating equipment motor starters, variable-speed drives and other electrical components such as contactors and circuit breakers are also used as final elements and their failure modes must be analyzed and proof tested.The primary failure modes for valves are being stuck, response time too slow or too fast, and leakage, all of which are affected by the valve’s operating process interface at trip time. While testing the valve at operating conditions is the most desirable case, Operations would generally be opposed to tripping the SIF while the plant is operating. Most SIS valves are typically tested while the plant is down at zero differential pressure, which is the least demanding of operating conditions. The user should be aware of the worst-case operational differential pressure and the valve and process degradation effects, which should be factored into the valve and actuator design and sizing.Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).Ambient temperatures can also affect valve friction loads, so that testing valves in warm weather will generally be the least demanding friction load when compared to cold weather operation. As a result, proof testing of valves at a consistent temperature should be considered to provide consistent data for inferential testing for the determination of valve performance degradation.Valves with smart positioners or a digital valve controller generally have capability to create a valve signature that can be used to monitor degradation in valve performance. A baseline valve signature can be requested as part of your purchase order or you can create one during the initial proof test to serve as a baseline. The valve signature should be done for both opening and closing of the valve. Advanced valve diagnostic should also be used if available. This can help tell you if your valve performance is deteriorating by comparing subsequent proof test valve signatures and diagnostics with your baseline. This type of test can help compensate for not testing the valve at worst case operating pressures.The valve signature during a proof test may also be able to record the response time with time stamps, removing the need for a stopwatch. Increased response time is a sign of valve deterioration and increased friction load to move the valve. While there are no standards regarding changes in valve response time, a negative pattern of changes from proof test to proof test is indicative of the potential loss of the valve’s safety margin and performance. Modern SIS valve proof testing should include a valve signature as a matter of good engineering practice.The valve instrument air supply pressure should be measured during a proof test. While the valve spring for a spring-return valve is what closes the valve, the force or torque involved is determined by how much the valve spring is compressed by the valve supply pressure (per Hooke’s Law, F = kX). If your supply pressure is low, the spring will not compress as much, hence less force will be available to move the valve when needed. While not inclusive, some of the things to consider in creating the valve portion of the proof test procedure are given in Table 2. Table 2: Final element valve assembly considerations Test valve safety action at process operating pressure (best but typically not done), and time the valve’s response time. Verify redundancy Test valve safety action at zero differential pressure and time valve’s response time. Verify redundancy Run valve signature and diagnostics as part of proof test and compare to baseline and previous test Visually observe valve action (proper action without unusual vibration or noise, etc.). Verify the valve field and position indication on the DCS Fully stroke the valve a minimum of five times during the proof test to help ensure valve reliability. (This is not intended to fix significant degradation effects or incipient failures). Review valve maintenance records to ensure any changes meet the required valve SRS specifications Test diagnostics for energize-to-trip systems Leak test if Tight Shut Off (TSO) is required Verify the command disagree alarm functionality Inspect valve assembly and internals Remove, test and rebuild as necessary Complete as-found and as-left documentation Solenoids Evaluate venting to provide required response time Evaluate solenoid performance by a digital valve controller or smart positioner Verify redundant solenoid performance (e.g. 1oo2, 2oo3) Interposing Relays Verify correct operation, redundancy Device inspection
A SIF biasane dipérang dadi telung bagean utama, sensor, solver logika lan unsur pungkasan. Biasane uga ana piranti tambahan sing bisa digandhengake ing saben telung bagean kasebut (contone, penghalang IS, amps trip, relay interposing, solenoid, lsp.) sing uga kudu diuji.
Tes bukti sensor: Tes bukti sensor kudu mesthekake yen sensor bisa ngerteni variabel proses kanthi lengkap lan ngirim sinyal sing tepat menyang solver logika SIS kanggo evaluasi. Sanajan ora kalebu, sawetara perkara sing kudu ditimbang nalika nggawe bagean sensor saka prosedur uji bukti diwenehi ing Tabel 1.
Tes bukti solver logika: Nalika tes bukti fungsi lengkap rampung, bagean solver logika kanggo ngrampungake aksi safety SIF lan tumindak sing gegandhengan (contone, weker, reset, bypass, diagnostik pangguna, redundansi, HMI, lsp.) dites. Tes bukti fungsi parsial utawa sepotong kudu ngrampungake kabeh tes kasebut minangka bagean saka tes bukti sing tumpang tindih. Pabrik solver logika kudu duwe prosedur uji bukti sing disaranake ing manual safety piranti. Yen ora lan minangka minimal, daya solver logika kudu cycled, lan logic solver ndhaftar diagnostik, lampu status, voltase sumber daya, pranala komunikasi lan redundansi kudu dicenthang. Pemriksaan kasebut kudu ditindakake sadurunge tes bukti fungsi lengkap.
Aja nganggep manawa piranti lunak kasebut apik ing salawas-lawase lan logika ora kudu diuji sawise tes bukti awal amarga owah-owahan piranti lunak lan piranti keras sing ora didokumentasikake, ora sah lan ora diuji lan nganyari piranti lunak bisa nyerbu sistem liwat wektu lan kudu dianggep dadi sakabehe. filosofi tes bukti. Manajemen log owah-owahan, pangopènan, lan revisi kudu ditinjau kanggo mesthekake yen lagi anyar lan dijaga kanthi bener, lan yen bisa, program aplikasi kudu dibandhingake karo cadangan paling anyar.
Ati-ati uga kudu ditindakake kanggo nyoba kabeh fungsi bantu lan diagnostik pemecah logika pangguna (contone, pengawas, tautan komunikasi, piranti keamanan siber, lsp.).
Tes bukti unsur pungkasan: Umume unsur pungkasan yaiku katup, nanging peralatan puteran wiwitan motor, drive kacepetan variabel lan komponen listrik liyane kayata kontaktor lan pemutus sirkuit uga digunakake minangka unsur pungkasan lan mode kegagalan kudu dianalisis lan diuji bukti.
Mode kegagalan utama kanggo katup lagi macet, wektu nanggepi alon banget utawa cepet banget, lan bocor, kabeh kena pengaruh antarmuka proses operasi katup ing wektu trip. Nalika nguji katup ing kahanan operasi minangka kasus sing paling dikarepake, Operasi umume bakal nentang nyepelekake SIF nalika pabrik beroperasi. Umume katup SIS biasane dites nalika tanduran mudhun ing tekanan diferensial nol, sing paling ora nuntut ing kahanan operasi. Pangguna kudu ngerti babagan tekanan diferensial operasional sing paling awon lan efek degradasi katup lan proses, sing kudu dipikirake ing desain lan ukuran katup lan aktuator.
Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).
Suhu sekitar uga bisa mengaruhi beban gesekan katup, supaya katup tes ing cuaca sing anget umume bakal dadi beban gesekan sing paling sithik yen dibandhingake karo operasi cuaca sing adhem. Akibaté, tes bukti katup ing suhu sing konsisten kudu dianggep nyedhiyakake data sing konsisten kanggo tes inferensial kanggo nemtokake degradasi kinerja katup.
Katup kanthi posisi pinter utawa pengontrol katup digital umume duwe kemampuan kanggo nggawe tandha katup sing bisa digunakake kanggo ngawasi degradasi kinerja katup. Tandha katup baseline bisa dijaluk minangka bagean saka pesenan tuku utawa sampeyan bisa nggawe siji sajrone tes bukti awal kanggo dadi garis dasar. Tandha katup kudu ditindakake kanggo mbukak lan nutup tutup. Diagnosa katup lanjut uga kudu digunakake yen kasedhiya. Iki bisa mbantu sampeyan ngerti yen kinerja katup saya mundhak kanthi mbandhingake tandha tandha lan diagnostik katup tes bukti sabanjure karo garis dasar sampeyan. Tes jinis iki bisa mbantu ngimbangi ora nguji katup ing tekanan operasi paling awon.
Tandha katup sajrone tes bukti bisa uga bisa ngrekam wektu nanggepi kanthi prangko wektu, ora mbutuhake stopwatch. Tambah wektu respon minangka tandha rusak katup lan tambah beban gesekan kanggo mindhah katup. Nalika ora ana standar babagan owah-owahan ing wektu nanggepi katup, pola negatif saka owah-owahan saka tes bukti dadi tes bukti nuduhake potensial mundhut wates safety lan kinerja katup. Pengujian bukti katup SIS modern kudu kalebu tandha katup minangka prakara praktik teknik sing apik.
Tekanan pasokan udara instrumen katup kudu diukur sajrone tes bukti. Nalika spring katup kanggo katup spring-bali iku apa nutup tutup, pasukan utawa torsi melu ditemtokake dening pinten spring katup wis teken dening meksa sumber katup (saben Hukum Hooke, F = kX). Yen tekanan pasokan kurang, spring ora bakal ngompres, mula kurang kekuwatan bakal kasedhiya kanggo mindhah katup nalika dibutuhake. Sanajan ora kalebu, sawetara perkara sing kudu ditimbang nalika nggawe bagean katup saka prosedur uji bukti diwenehi ing Tabel 2.
Wektu kirim: Nov-13-2019
