Fan balansi
(Information used from GOST 31350-2007 “VIBRATION. INDUSTRIAL FANS. REQUIREMENTS FOR PRODUCED VIBRATION AND BALANCING QUALITY” — an interstate standard developed from ISO 14694:2003 “Industrial fans — Specifications for balance quality and vibration levels”)
Source note: this page is based on the fan vibration and balance quality requirements equivalent to ISO 14694:2003 and related interstate (GOST) adoptions of ISO standards, whose designations differ from the original ISO publication numbers. Where older ISO 1940-1 terminology appears, the current balance quality standard is ISO 21940-11 (formerly ISO 1940-1).
Vibration Fan tomonidan ishlab chiqarilgan tebranish uning eng muhim texnik xususiyatlaridan biridir. Bu mahsulot dizayni va ishlab chiqarish sifatini ko'rsatadi. Tebranishning kuchayishi fanning noto'g'ri o'rnatilishini, uning texnik holatining yomonlashishini va hokazolarni ko'rsatishi mumkin.Shu sababli, fanning tebranishi odatda qabul sinovlari paytida, ishga tushirishdan oldin o'rnatish vaqtida, shuningdek, mashina holatini kuzatish dasturini bajarishda o'lchanadi. Fanning tebranish ma'lumotlari, shuningdek, uni qo'llab-quvvatlash va ulangan tizimlarni (kanallarni) loyihalashda ham qo'llaniladi. Vibratsiyani o'lchash odatda ochiq assimilyatsiya va tushirish portlari bilan amalga oshiriladi, ammo shuni ta'kidlash kerakki, fanning tebranishi havo oqimi aerodinamikasining o'zgarishi, aylanish tezligi va boshqa xususiyatlar bilan sezilarli darajada farq qilishi mumkin.
GOST ISO 10816-1-97 (ISO 10816-1:1995), GOST ISO 10816-3-2002 (ISO 10816-3:1998), and GOST 31351-2007 (ISO 14695:2003) establish measurement methods and define vibration sensor locations. If vibration measurements are carried out to assess their impact on the duct or fan base, the measurement points are chosen accordingly.
Fanning tebranishini o'lchash qimmat bo'lishi mumkin va ba'zida ularning narxi mahsulotning o'zini ishlab chiqarish xarajatlaridan sezilarli darajada oshadi. Shuning uchun, individual diskret tebranish komponentlarining qiymatlari yoki chastota diapazonidagi tebranish parametrlari bo'yicha har qanday cheklovlar faqat ushbu qiymatlardan oshib ketganda fanning noto'g'ri ishlashini ko'rsatadigan hollarda kiritilishi kerak. Vibratsiyani o'lchash nuqtalarining soni ham o'lchov natijalaridan maqsadli foydalanish asosida cheklanishi kerak. Odatda, fanning tebranish holatini baholash uchun fan tayanchlarida tebranishlarni o'lchash kifoya.
Baza fanning o'rnatilgani va fan uchun kerakli yordamni ta'minlaydigan narsadir. Poydevorning massasi va qattiqligi u orqali uzatiladigan tebranishning kuchayishini oldini olish uchun tanlanadi.
Qo'llab-quvvatlashlar ikki xil:
- mos keladigan qo'llab-quvvatlash: qo'llab-quvvatlashning birinchi tabiiy chastotasi fanning ish aylanish chastotasidan sezilarli darajada past bo'lishi uchun mo'ljallangan fanni qo'llab-quvvatlash tizimi. Qo'llab-quvvatlashning muvofiqlik darajasini aniqlashda fan va qo'llab-quvvatlash tuzilishi o'rtasidagi elastik qo'shimchalarni hisobga olish kerak. Qo'llab-quvvatlashning muvofiqligi fanni kamonlarga osib qo'yish yoki tayanchni elastik elementlarga (prujkalar, kauchuk izolyatorlar va boshqalar) joylashtirish orqali ta'minlanadi. Osma tizimning tabiiy chastotasi - fan odatda sinovdan o'tgan fanning minimal aylanish tezligiga mos keladigan chastotaning 25% dan kam.
- qattiq qo'llab-quvvatlash: qo'llab-quvvatlashning birinchi tabiiy chastotasi ish aylanish chastotasidan sezilarli darajada yuqori bo'lishi uchun mo'ljallangan fanni qo'llab-quvvatlash tizimi. Fan bazasining qattiqligi nisbiydir. Mashinaning rulmanlarining qattiqligi bilan solishtirganda hisobga olinishi kerak. Rulman korpusining tebranishini taglik tebranishiga nisbati bazaning muvofiqligi ta'sirini tavsiflaydi. Mashinaning oyoqlari yoki qo'llab-quvvatlash ramkasi yaqinidagi asosiy tebranishning (har qanday yo'nalishda) amplitudasi eng yaqin rulman tayanchida (har qanday yo'nalishda) olingan maksimal tebranish o'lchash natijasining 25% dan kam bo'lsa, bazani qattiq va etarlicha massiv deb hisoblash mumkin.
Zavod sinovi paytida fan o'rnatilgan vaqtinchalik poydevorning massasi va qattiqligi ish joyidagi o'rnatish shartlaridan sezilarli darajada farq qilishi mumkinligi sababli, zavod shartlarining chegara qiymatlari aylanish chastotasi diapazonidagi tor diapazonli tebranish uchun qo'llaniladi. joyida fan sinovi - keng polosali tebranish uchun, mashinaning umumiy tebranish holatini aniqlash. Operatsion sayt fanning oxirgi o'rnatish joyi bo'lib, uning uchun ish sharoitlari aniqlanadi.
Muxlislar toifalari (BV-toifalari)
Ventilatorlar mo'ljallangan foydalanish xususiyatlariga ko'ra tasniflanadi, balanslash aniqligi sinflari, va tavsiya etilgan tebranish parametrining chegaraviy qiymatlari. Ventilatorning konstruksiyasi va maqsadi ko'p turdagi ventilatorlarni ruxsat etilgan imbalance qiymatlari va tebranish darajalari (BV-kategoriyalari) bo'yicha tasniflash imkonini beruvchi mezonlardir.
1-jadvalda ruxsat etilgan nomutanosiblik qiymatlari va tebranish darajalarini hisobga olgan holda, fanatlarni qo'llash shartlariga ko'ra, qaysi toifalarga kiritish mumkinligi ko'rsatilgan. Fan toifasi ishlab chiqaruvchi tomonidan belgilanadi.
1-jadval – Muxlislar toifalari
| Qo'llash shartlari | Misollar | Quvvat iste'moli, kVt | BV toifasi |
| Turar-joy va ofis xonalari | Shift va chordoq fanatlari, deraza konditsionerlari | ≤ 0,15 | BV-1 |
| > 0,15 | BV-2 | ||
| Binolar va qishloq xo'jaligi binolari | Shamollatish va konditsioner tizimlari uchun fanatlar; Uskunalar seriyasidagi muxlislar | ≤ 3.7 | BV-2 |
| > 3.7 | BV-3 | ||
| Sanoat jarayonlari va energiya ishlab chiqarish | Yopiq maydonlardagi fanatlar, konlar, konveyerlar, qozonxonalar, shamol tunnellari, gazni tozalash tizimlari | ≤ 300 | BV-3 |
| > 300 | ISO 10816-3 ga qarang | ||
| Transport, shu jumladan dengiz kemalari | Lokomotivlar, yuk mashinalari va avtomobillardagi muxlislar | ≤ 15 | BV-3 |
| > 15 | BV-4 | ||
| Tunnellar | Metro, tunnel, garajlarni ventilyatsiya qilish uchun fanatlar | ≤ 75 | BV-3 |
| > 75 | BV-4 | ||
| Har qanday | BV-4 | ||
| Neft-kimyo ishlab chiqarish | Xavfli gazlarni olib tashlash uchun fanatlar va boshqa texnologik jarayonlarda qo'llaniladi | ≤ 37 | BV-3 |
| > 37 | BV-4 | ||
| Kompyuter chiplari ishlab chiqarish | Toza xonalarni yaratish uchun muxlislar | Har qanday | BV-5 |
| Notes
1 This standard only considers fans with power less than 300 kW. The vibration assessment of fans with greater power is according to ISO 10816-3. However, standard series electric motors can have a rated power of up to 355 kW. Fans with such electric motors should be accepted according to this standard.
2 Table 1 does not apply to large diameter (usually from 2800 to 12500 mm) low-speed light axial fans used in heat exchangers, cooling towers, etc. The balancing accuracy class for such fans should be G16, and the fan category – BV-3
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When purchasing individual rotor elements (wheels or impellers) for subsequent installation on the fan, the balancing accuracy class of these elements (see table 2) should be followed, and when purchasing the fan as a whole, the results of factory vibration tests (table 4) and on-site vibration (table 5) should also be considered. Usually, these characteristics are agreed upon, so the choice of fan can be made based on its BV-category.
The category established in table 1 is typical for the normal use of fans, but in justified cases, the customer may request a fan of a different BV-category. It is recommended to specify the fan’s BV-category, balancing accuracy class, and acceptable vibration levels in the equipment supply contract.
A separate agreement between the customer and the manufacturer can be concluded regarding the fan installation conditions, so that the factory testing of the assembled fan considers the planned installation conditions at the operating site. In the absence of such an agreement, there are no restrictions on the type of base (rigid or compliant) for factory tests.
Fan balansi
General Provisions
Ventilator ishlab chiqaruvchisi mas'uliyat yuklaydi muvozanatlash tegishli me'yoriy hujjatga muvofiq ventilatorlar. Ushbu standart quyidagi talablarga asoslanadi: ISO 1940-1. Balanslashtirish odatda yuqori sezgirlikka ega, maxsus ishlab chiqilgan balanslashtirish mashinalarida, bu qoldiq muvozanatsizlikni aniq baholash imkonini beradi qoldiq muvozanatsizlik.
Fan Balancing Accuracy Classes
The balancing accuracy classes for fan wheels are applied in accordance with table 2. The fan manufacturer can perform balancing for several elements in assembly, which may include, in addition to the wheel, the shaft, coupling, pulley, etc. In addition, individual assembly elements may require balancing.
Table 2 – Balancing Accuracy Classes
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Fan Category
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Rotor (Wheel) Balancing Accuracy Class
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BV-1
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G16
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BV-2
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G16
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BV-3
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G6.3
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BV-4
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G2.5
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BV-5
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G1.0
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Note: Fans of category BV-1 can include small size fans weighing less than 224 g, for which it is difficult to maintain the specified balancing accuracy. In this case, the uniformity of mass distribution relative to the fan’s axis of rotation should be ensured by the manufacturing technology.
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Fan Vibration Measurement
Measurement Requirements
General Provisions
Figures 1 – 4 show some possible measurement points and directions on each fan bearing. The values given in table 4 relate to measurements in the direction perpendicular to the axis of rotation. The number and location of measurement points for both factory tests and on-site measurements are determined at the manufacturer’s discretion or by agreement with the customer. It is recommended to measure on the bearings of the fan wheel shaft (impeller). If this is not possible, the sensor should be installed in a place where the shortest mechanical connection between it and the bearing is ensured. The sensor should not be mounted on unsupported panels, the fan housing, enclosure elements, or other places not directly connected to the bearing (such measurement results can be used, but not for assessing the fan’s vibrational state, but for obtaining information about the vibration transmitted to the duct or base – see ISO 14695 (GOST 31351) and ISO 5348.
Figure 1. Location of a three-coordinate sensor for a horizontally mounted axial fan
Figure 2. Location of a three-coordinate sensor for a single-suction radial fan
Figure 3. Location of a three-coordinate sensor for a double-suction radial fan
Figure 4. Location of a three-coordinate sensor for a vertically mounted axial fan
Measurements in the horizontal direction should be carried out at a right angle to the shaft axis. Measurements in the vertical direction should be carried out at a right angle to the horizontal measurement direction and perpendicular to the fan shaft. Measurements in the longitudinal direction should be carried out parallel to the shaft axis.
Measurements using inertia-type sensors
All vibration values specified in this standard refer to measurements taken using inertia-type sensors, the signal of which reproduces the movement of the bearing housing.
The sensors used can be either accelerometers or velocity sensors. Particular attention should be paid to the correct attachment of sensors: without gaps on the support surface, without swings and resonances. The size and mass of the sensors and the attachment system should not be excessively large to avoid significant changes in the measured vibration. The total error caused by the method of sensor attachment and calibration of the measuring system should not exceed +/- 10% of the measured value.
Measurements using non-contact sensors
By agreement between the user and the manufacturer, requirements for the maximum allowable shaft displacement (see ISO 7919-1) within sliding bearings may be established. The corresponding measurements can be carried out using non-contact sensors.
In this case, the measuring system determines the displacement of the shaft surface relative to the bearing housing. It is obvious that the allowable amplitude of displacements should not exceed the value of the bearing clearance. The clearance value depends on the size and type of bearing, the load (radial or axial), and the measurement direction (some bearing designs have an elliptical hole, for which the clearance in the horizontal direction is greater than in the vertical direction). The variety of factors that need to be considered does not allow setting uniform shaft displacement limits, but some recommendations are presented in table 3. The values given in this table represent a percentage of the total radial clearance value in the bearing in each direction.
Table 3 – Maximum Relative Shaft Displacement within the Bearing
| Fan Vibrational State | Maximum Recommended Displacement, Percentage of Clearance Value (Along Any Axis) |
| Commissioning/Satisfactory State | Less than 25% |
| Warning | +50% |
| Shutdown | +70% |
| 1) Radial and axial clearance values for a specific bearing should be obtained from its supplier. | |
The given values take into account “false” displacements of the shaft surface. These “false” displacements appear in the measurement results because, in addition to the shaft vibration, mechanical runouts also affect these results if the shaft is bent or has an out-of-round shape. When using a non-contact sensor, the measurement results will also include electrical runouts determined by the magnetic and electrical properties of the shaft material at the measurement point. It is believed that during the commissioning and subsequent normal operation of the fan, the range of the sum of mechanical and electrical runouts at the measurement point should not exceed the larger of two values: 0.0125 mm or 25% of the measured displacement value. Runouts are determined by slowly rotating the shaft (at a speed of 25 to 400 rpm), when the effect of forces caused by imbalance on the rotor is negligible. To meet the established runout tolerance, additional shaft machining may be required. Non-contact sensors should, if possible, be mounted directly on the bearing housing.
The given limit values apply only to a fan operating in its nominal mode. If the fan design allows operation with variable rotational speed, higher vibration levels are possible at other speeds due to the inevitable influence of resonances.
If the fan design allows changing the blade positions relative to the airflow at the intake port, the given values should be applied for conditions with the blades fully open. It should be noted that airflow stall, especially noticeable at large blade angles relative to the intake airflow, can lead to increased vibration levels.
Fan Support System
The vibrational state of fans after installation is determined considering the support stiffness. A support is considered rigid if the first natural frequency of the “fan – support” system exceeds the rotational speed. Usually, when mounted on large concrete foundations, the support can be considered rigid, and when mounted on vibration isolators – compliant. A steel frame, often used for mounting fans, can belong to either of the two support types. In case of doubt about the fan support type, calculations or tests can be carried out to determine the system’s first natural frequency. In some cases, the fan support should be considered rigid in one direction and compliant in another.
Limits of Allowable Fan Vibration during Factory Tests
The limit vibration levels given in table 4 apply to assembled fans. They relate to narrow-band vibration velocity measurements at bearing supports for the rotational frequency used during factory tests.
Table 4 – Limit Vibration Values during Factory Tests
| Fan Category | Limit RMS Vibration Velocity, mm/s | |
| Rigid Support | Mos keladigan qo'llab-quvvatlash | |
| BV-1 | 9.0 | 11.2 |
| BV-2 | 3.5 | 5.6 |
| BV-3 | 2.8 | 3.5 |
| BV-4 | 1.8 | 2.8 |
| BV-5 | 1.4 | 1.8 |
| Notes
1 Tor diapazonli tebranish uchun tebranish tezligi birliklarini siljish yoki tezlashtirish birliklariga aylantirish qoidalari A ilovasida keltirilgan.
2 Ushbu jadvaldagi qiymatlar ochiq kirish yo'riqnomasi qanotlari bilan rejimda ishlaydigan fanning nominal yuki va nominal aylanish chastotasiga tegishli. Boshqa yuklash shartlari uchun chegara qiymatlari ishlab chiqaruvchi va mijoz o'rtasida kelishilgan bo'lishi kerak, ammo ular jadval ko'rsatkichlaridan 1,6 martadan oshmasligi tavsiya etiladi.
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Saytda sinovdan o'tkazishda ruxsat etilgan fan tebranishlarining chegaralari
Har qanday fanning ish joyidagi tebranishi nafaqat uning muvozanatlash sifatiga bog'liq. O'rnatish bilan bog'liq omillar, masalan, qo'llab-quvvatlash tizimining massasi va qattiqligi ham ta'sir qiladi. Shuning uchun, fan ishlab chiqaruvchisi, agar shartnomada ko'rsatilmagan bo'lsa, ish joyidagi fanning tebranish darajasi uchun javobgar emas.
5-jadvalda turli toifadagi fanatlarning normal ishlashi uchun tavsiya etilgan chegara qiymatlari (rulman korpuslarida keng polosali tebranish uchun tebranish tezligi birliklarida) keltirilgan.
5-jadval - Operatsion maydonchada tebranish qiymatlarini cheklash
| Fan Vibrational State | Fan Category | Limit RMS Vibration Velocity, mm/s | |
| Rigid Support | Mos keladigan qo'llab-quvvatlash | ||
| Ishga tushirish | BV-1 | 10 | 11.2 |
| BV-2 | 5.6 | 9.0 | |
| BV-3 | 4.5 | 6.3 | |
| BV-4 | 2.8 | 4.5 | |
| BV-5 | 1.8 | 2.8 | |
| Warning | BV-1 | 10.6 | 14.0 |
| BV-2 | 9.0 | 14.0 | |
| BV-3 | 7.1 | 11.8 | |
| BV-4 | 4.5 | 7.1 | |
| BV-5 | 4.0 | 5.6 | |
| Shutdown | BV-1 | __1) | __1) |
| BV-2 | __1) | __1) | |
| BV-3 | 9.0 | 12.5 | |
| BV-4 | 7.1 | 11.2 | |
| BV-5 | 5.6 | 7.1 | |
| 1) BV-1 va BV-2 toifalari muxlislari uchun o'chirish darajasi tebranishlarni o'lchash natijalarini uzoq muddatli tahlil qilish asosida belgilanadi. | |||
Ishga qabul qilinayotgan yangi fanatlarning tebranishi "ishga tushirish" darajasidan oshmasligi kerak. Fan ishlaganda, uning tebranish darajasi eskirish jarayonlari va ta'sir etuvchi omillarning yig'indisi ta'siri tufayli oshishi kutilmoqda. Vibratsiyaning bunday o'sishi odatda tabiiydir va u "ogohlantirish" darajasiga yetguncha tashvish tug'dirmasligi kerak.
"Ogohlantirish" tebranish darajasiga erishgandan so'ng, tebranishning kuchayishi sabablarini o'rganish va uni kamaytirish choralarini aniqlash kerak. Ushbu holatda fanning ishlashi doimiy nazorat ostida bo'lishi va tebranishning kuchayishi sabablarini bartaraf etish choralarini aniqlash uchun zarur bo'lgan vaqt bilan cheklanishi kerak.
Agar tebranish darajasi "o'chirish" darajasiga yetsa, tebranishning kuchayishi sabablarini bartaraf etish choralarini darhol ko'rish kerak, aks holda fanni to'xtatish kerak. Vibratsiya darajasini maqbul darajaga etkazishni kechiktirish podshipnikning shikastlanishiga, rotordagi yoriqlarga va fan korpusining payvandlash joylariga olib kelishi mumkin, natijada fanning nobud bo'lishiga olib keladi.
Fanning tebranish holatini baholashda vaqt o'tishi bilan tebranish darajasidagi o'zgarishlarni kuzatish juda muhimdir. Vibratsiya darajasining keskin o'zgarishi fanni zudlik bilan tekshirish va texnik xizmat ko'rsatish choralarini ko'rish zarurligini ko'rsatadi. Vibratsiyali o'zgarishlarni kuzatishda, masalan, moylash materiallarini almashtirish yoki texnik xizmat ko'rsatish tartib-qoidalari tufayli yuzaga keladigan o'tish jarayonlarini hisobga olmaslik kerak.
Yig'ilish tartibining ta'siri
G'ildiraklarga qo'shimcha ravishda fanatlar fanning tebranish darajasiga ta'sir qilishi mumkin bo'lgan boshqa aylanadigan elementlarni o'z ichiga oladi: haydovchi kasnaklar, kamarlar, muftalar, motor rotorlari yoki boshqa haydovchi qurilmalar. Agar buyurtma shartlari fanni haydovchi qurilmasisiz etkazib berishni talab qilsa, ishlab chiqaruvchining tebranish darajasini aniqlash uchun montaj sinovlarini o'tkazish mantiqiy bo'lmasligi mumkin. Bunday holatda, ishlab chiqaruvchi fan g'ildiragini muvozanatlashtirgan bo'lsa ham, fan mili haydovchiga ulanmaguncha va ishga tushirish vaqtida butun mashina tebranish uchun sinovdan o'tkazilgunga qadar fanning muammosiz ishlashiga ishonch yo'q.
Odatda, montajdan so'ng, tebranish darajasini maqbul darajaga tushirish uchun qo'shimcha muvozanat talab qilinadi. BV-3, BV-4 va BV-5 toifalarining barcha yangi muxlislari uchun ishga tushirishdan oldin yig'ilgan mashina uchun tebranishlarni o'lchash tavsiya etiladi. Bu bazani yaratadi va keyingi parvarishlash choralarini belgilaydi.
Fan ishlab chiqaruvchilari zavod sinovidan so'ng o'rnatilgan qo'zg'aysan qismlarining tebranishiga ta'siri uchun javobgar emas.
Vibratsiyani o'lchash asboblari va kalibrlash
O'lchov asboblari
Amaldagi o'lchov asboblari va balanslash mashinalari tekshirilishi va topshiriq talablariga javob berishi kerak. Tekshiruvlar orasidagi interval ishlab chiqaruvchining o'lchov (sinov) asboblari bo'yicha tavsiyalari bilan belgilanadi. O'lchov vositalarining holati ularning sinov muddati davomida normal ishlashini ta'minlashi kerak.
O'lchov vositalari bilan ishlaydigan xodimlar mumkin bo'lgan nosozliklar va o'lchov vositalarining sifati yomonlashishini aniqlash uchun etarli ko'nikma va tajribaga ega bo'lishi kerak.
Kalibrlash
Barcha o'lchov asboblari standartlarga muvofiq kalibrlangan bo'lishi kerak. Kalibrlash protsedurasining murakkabligi oddiy jismoniy tekshiruvdan butun tizimni kalibrlashgacha farq qilishi mumkin. ISO 1940-1 ga muvofiq qoldiq nomutanosiblikni aniqlash uchun ishlatiladigan tuzatuvchi massalar o'lchov vositalarini kalibrlash uchun ham ishlatilishi mumkin.
Hujjatlar
Balancing
Agar so'rov bo'yicha, agar shartnoma shartlarida nazarda tutilgan bo'lsa, mijozga quyidagi ma'lumotlarni o'z ichiga olishi tavsiya etiladigan fan balansi sinov hisoboti taqdim etilishi mumkin:
– balanslash mashinasi ishlab chiqaruvchisining nomi, model raqami;
– Rotorni o'rnatish turi: tayanchlar o'rtasida yoki konsolli;
– Balanslash usuli: statik yoki dinamik;
– Rotor majmuasining aylanuvchi qismlarining massasi;
– Har bir tekislikdagi qoldiq muvozanatsizlik tuzatish tekisligi (use our qoldiq muvozanatsizlik kalkulyatori (ISO 21940-11) ruxsat etilgan qiymatlarni aniqlash uchun);
– Har bir tuzatish tekisligida ruxsat etilgan qoldiq nomutanosiblik;
– Balanslash aniqlik klassi;
– Qabul qilish mezonlari: qabul qilingan/rad etilgan;
- Balans sertifikati (agar kerak bo'lsa).
– balanslash mashinasi ishlab chiqaruvchisining nomi, model raqami;
– Rotorni o'rnatish turi: tayanchlar o'rtasida yoki konsolli;
– Balanslash usuli: statik yoki dinamik;
– Rotor majmuasining aylanuvchi qismlarining massasi;
– Har bir tekislikdagi qoldiq muvozanatsizlik tuzatish tekisligi (use our qoldiq muvozanatsizlik kalkulyatori (ISO 21940-11) ruxsat etilgan qiymatlarni aniqlash uchun);
– Har bir tuzatish tekisligida ruxsat etilgan qoldiq nomutanosiblik;
– Balanslash aniqlik klassi;
– Qabul qilish mezonlari: qabul qilingan/rad etilgan;
- Balans sertifikati (agar kerak bo'lsa).
Vibration
Agar so'rov bo'yicha, agar shartnoma shartlarida nazarda tutilgan bo'lsa, mijozga fanning tebranishini tekshirish hisoboti taqdim etilishi mumkin, unda quyidagi ma'lumotlarni kiritish tavsiya etiladi:
– Amaldagi o‘lchov vositalari;
– tebranish datchigini biriktirish usuli;
– Fanning ish parametrlari (havo oqimi, bosim, quvvat);
– Fan aylanish chastotasi;
– Qo‘llab-quvvatlash turi: qattiq yoki mos;
- o'lchangan tebranish:
1) tebranish sensori pozitsiyalari va o'lchov o'qlari,
2) o'lchov birliklari va tebranish mos yozuvlar darajalari,
3) o'lchash chastota diapazoni (tor yoki keng chastota diapazoni);
– Ruxsat etilgan tebranish darajasi(lar);
– o‘lchangan tebranish darajasi(lar);
– Qabul qilish mezonlari: qabul qilingan/rad etilgan;
– Vibratsiya darajasi sertifikati (agar kerak bo'lsa).
– Amaldagi o‘lchov vositalari;
– tebranish datchigini biriktirish usuli;
– Fanning ish parametrlari (havo oqimi, bosim, quvvat);
– Fan aylanish chastotasi;
– Qo‘llab-quvvatlash turi: qattiq yoki mos;
- o'lchangan tebranish:
1) tebranish sensori pozitsiyalari va o'lchov o'qlari,
2) o'lchov birliklari va tebranish mos yozuvlar darajalari,
3) o'lchash chastota diapazoni (tor yoki keng chastota diapazoni);
– Ruxsat etilgan tebranish darajasi(lar);
– o‘lchangan tebranish darajasi(lar);
– Qabul qilish mezonlari: qabul qilingan/rad etilgan;
– Vibratsiya darajasi sertifikati (agar kerak bo'lsa).
MUVAZONLASHTIRISH MOSHINADA MUVOZONLASHTIRISH USULLARI
B.1. To'g'ridan-to'g'ri haydovchi fan
B.1.1. Umumiy qoidalar
The fan wheel, which is mounted directly on the motor shaft during assembly, should be balanced according to the same rule for accounting for the keyway effect as for the motor shaft.
Motors from previous years of production could be balanced using a full keyway. Currently, motor shafts are balanced using a half-keyway, as prescribed by ISO 8821 (adopted as GOST 31322), and marked with the letter H (see ISO 8821).
B.1.2. Motors Balanced with a Full Keyway
The fan wheel, mounted on the motor shaft balanced with a full keyway, should be balanced without a key on a tapered arbor.
B.1.3. Motors Balanced with a Half-Keyway
For the fan wheel mounted on the motor shaft balanced with a half-keyway, the following options are possible:
a) if the wheel has a steel hub, cut a keyway in it after balancing;
b) balance on a tapered arbor with a half-key inserted into the keyway;
c) balance on an arbor with one or more keyways (see B.3), using full keys.
a) if the wheel has a steel hub, cut a keyway in it after balancing;
b) balance on a tapered arbor with a half-key inserted into the keyway;
c) balance on an arbor with one or more keyways (see B.3), using full keys.
B.2. Fans Driven by Another Shaft
Where possible, all rotating elements, including the fan shaft and pulley, should be balanced as a single unit. If this is impractical, balancing should be performed on an arbor (see B.3) using the same keyway accounting rule as for the shaft.
B.3. Arbor
The arbor on which the fan wheel is mounted during balancing must meet the following requirements:
a) be as light as possible;
b) be in a balanced state, ensured by appropriate maintenance and regular inspections;
c) preferably be tapered to reduce errors associated with eccentricity, resulting from the tolerances of the hub hole and arbor dimensions. If the arbor is tapered, the true position of the correction planes relative to the bearings should be considered in the imbalance calculations.
a) be as light as possible;
b) be in a balanced state, ensured by appropriate maintenance and regular inspections;
c) preferably be tapered to reduce errors associated with eccentricity, resulting from the tolerances of the hub hole and arbor dimensions. If the arbor is tapered, the true position of the correction planes relative to the bearings should be considered in the imbalance calculations.
If it is necessary to use a cylindrical arbor, it should have a keyway cut into it, into which a full key is inserted to transmit the torque from the arbor to the fan wheel.
Another option is to cut two keyways on opposite ends of the shaft diameter, allowing the use of the reverse balancing method. This method involves the following steps. First, measure the wheel imbalance by inserting a full key into one keyway and a half-key into the other. Then rotate the wheel 180° relative to the arbor and measure its imbalance again. The difference between the two imbalance values is due to the residual imbalance of the arbor and the universal drive joint. To obtain the true rotor imbalance value, take half the difference of these two measurements.
SOURCES OF FAN VIBRATION
There are many sources of vibration within the fan, and vibration at certain frequencies can be directly linked to specific design features of the machine. This appendix only covers the most common vibration sources observed in most types of fans. The general rule is that any looseness in the support system causes deterioration in the fan’s vibrational state.
Fan Imbalance
Bu ventilator vibratsiyasining asosiy manbai bo'lib, aylanish chastotasida (birinchi harmonic). Muvozanatsizlikning sababi shundaki, aylanuvchi massa o'qi aylanish o'qiga nisbatan markazdan siljigan yoki qiyshiq joylashgan. Bu notekis massa taqsimoti, vtulka teshigi va val o'lchamlaridagi toleranslar yig'indisi, valning egilishi yoki ushbu omillar kombinatsiyasi tufayli yuzaga kelishi mumkin. Muvozanatsizlik natijasida vujudga kelgan vibratsiya asosan radial yo'nalishda ta'sir qiladi.
Temporary shaft bending can result from uneven mechanical heating – due to friction between rotating and stationary elements – or electrical nature. Permanent bending can result from changes in material properties or misalignment of the shaft and fan wheel when the fan and motor are separately mounted.
During operation, the fan wheel imbalance can increase due to particle deposition from the air. When operating in an aggressive environment, imbalance can result from uneven erosion or corrosion of the wheel.
Imbalance can be corrected by additional balancing in the appropriate planes, but before performing the balancing procedure, the sources of imbalance should be identified, eliminated, and the machine’s vibrational stability checked.
Fan and Motor Misalignment
This defect can occur when the motor and fan shafts are connected via a belt drive or flexible coupling. Misalignment can sometimes be identified by characteristic vibration frequency components, usually the first and second harmonics of the rotational frequency. In the case of parallel misalignment of the shafts, vibration primarily occurs in the radial direction, while if the shafts intersect at an angle, longitudinal vibration may become dominant.
If the shafts are connected at an angle and rigid couplings are used, alternating forces begin to act in the machine, causing increased wear of the shafts and couplings. This effect can be significantly reduced by using flexible couplings.
Fan Vibration Due to Aerodynamic Excitation
Vibratsiya qo'zg'alishi vентилятор g'ildiragi bilan konstruksiyaning statsionar elementlari — yo'naltiruvchi qanotlar, motor yoki podshipnik tayanchi — o'rtasidagi o'zaro ta'sir, noto'g'ri bo'shliq qiymatlari yoki noto'g'ri loyihalashtirilgan havo kirish va chiqish qurilmalari tufayli yuzaga kelishi mumkin. Ushbu manbalarning xarakterli xususiyati shundaki, g'ildirakning aylanish chastotasi bilan bog'liq davriy vibratsiya, g'ildirak qanatlari va havo o'rtasidagi o'zaro ta'sirning tasodifiy tebranishlari fonida namoyon bo'ladi. Vibratsiya quyidagilarda kuzatilishi mumkin: qanot chastotasi garmonikalari, bu g'ildirakning aylanish chastotasi va g'ildirakdagi qanotlar sonining ko'paytmasiga teng.
Aerodynamic instability of the airflow, caused by its stall from the blade surface and subsequent vortex formation, causes broadband vibration, the spectrum shape of which changes depending on the fan’s load.
Aerodynamic noise is characterized by the fact that it is not related to the wheel’s rotational frequency and can occur at subharmonics of the rotational frequency (i.e., at frequencies below the rotational frequency). In this case, significant vibration of the fan housing and ducts can be observed.
If the aerodynamic system of the fan is poorly matched with its characteristics, sharp impacts may occur in it. These impacts are easily distinguishable by ear and are transmitted as impulses to the fan support system.
If the above-mentioned causes lead to blade vibration, its nature can be investigated by installing sensors in different parts of the structure.
Fan Vibration Due to Whirl in the Oil Layer
Whirls that may occur in the lubrication layer of sliding bearings are observed at a characteristic frequency slightly below the rotor’s rotational frequency unless the fan operates at a speed exceeding the first critical. In the latter case, oil wedge instability will be observed at the first critical speed, and sometimes this effect is called resonant whirl.
Sources of Electrical Nature Fan Vibration
Uneven heating of the motor rotor can cause it to bend, leading to imbalance (manifesting at the first harmonic).
In the case of an asynchronous motor, the presence of a component at a frequency equal to the rotational frequency multiplied by the number of rotor plates indicates defects related to the stator plates, and vice versa, components at a frequency equal to the rotational frequency multiplied by the number of rotor plates indicate defects related to the rotor plates.
Many vibration components of electrical nature are characterized by their immediate disappearance when the power supply is turned off.
Fan Vibration Due to Belt Drive Excitation
Generally, there are two types of problems related to belt drives: when the drive’s operation is influenced by external defects and when the defects are in the belt itself.
In the first case, although the belt vibrates, this is due to forcing forces from other sources, so replacing the belt will not produce the desired results. Common sources of such forces are imbalance in the drive system, pulley eccentricity, misalignment, and loosened mechanical connections. Therefore, before changing the belts, vibration analysis should be carried out to identify the excitation source.
If the belts respond to external forcing forces, their vibration frequency will most likely be the same as the excitation frequency. In this case, the excitation frequency can be determined using a stroboscopic lamp, adjusting it so that the belt appears stationary in the lamp’s light.
In the case of a multi-belt drive, unequal belt tension can lead to a significant increase in the transmitted vibration.
Cases where the vibration sources are the belts themselves are related to their physical defects: cracks, hard and soft spots, dirt on the belt surface, missing material from its surface, etc. For V-belts, changes in their width will cause the belt to ride up and down the pulley track, creating vibration due to changing its tension.
If the vibration source is the belt itself, the vibration frequencies are usually the harmonics of the belt’s rotational frequency. In a specific case, the excitation frequency will depend on the nature of the defect and the number of pulleys, including tensioners.
In some cases, the vibration amplitude may be unstable. This is especially true for multi-belt drives.
Mechanical and electrical defects are sources of vibration, which subsequently convert into airborne noise. Mechanical noise can be associated with fan or motor imbalance, bearing noise, axis alignment, duct wall and housing panel vibrations, damper blade vibrations, blade, damper, pipe, and support vibrations, as well as transmission of mechanical vibrations through the structure. Electrical noise is related to various forms of electrical energy conversion: 1) Magnetic forces are determined by the magnetic flux density, the number and shape of the poles, and the geometry of the air gap; 2) Random electrical noise is determined by brushes, arcing, electrical sparks, etc.
Aerodynamic noise can be associated with vortex formation, pressure pulsations, air resistance, etc., and can have both broadband and narrowband nature. Broadband noise can be caused by: a) blades, dampers, and other obstacles in the airflow path; b) fan rotation as a whole, belts, slits, etc.; c) sudden changes in airflow direction or duct cross-section, differences in flow velocities, flow separation due to boundary effects, flow compression effects, etc. Narrowband noise can be caused by: a) resonances (organ pipe effect, string vibrations, panel, structural element vibrations, etc.); b) vortex formation on sharp edges (air column excitation); c) rotations (siren effect, slits, holes, slots on rotating parts).
Strukturaning turli mexanik elementlari oʻrtasidagi aloqa natijasida hosil boʻlgan taʼsirlar bolgʻacha urishi, momaqaldiroqning shovqini, rezonansli boʻsh quti va boshqalar natijasida hosil boʻladigan shovqinga oʻxshash shovqin hosil qiladi. Taʼsir tovushlari tishli tishlarning taʼsiridan va kamarning nuqsonli qarsaklaridan eshitiladi. Ta'sir impulslari shunchalik tez bo'lishi mumkinki, davriy ta'sir impulslarini vaqtinchalik jarayonlardan farqlash uchun maxsus yuqori tezlikda qayd etish uskunasi kerak. Ko'p zarba impulslari paydo bo'ladigan maydon, ularning cho'qqilarining bir-biriga qo'shilishi doimiy g'uvullash effektini yaratadi.
Vibratsiyaning fanni qo'llab-quvvatlash turiga bog'liqligi
Fanni qo'llab-quvvatlash yoki poydevor dizaynini to'g'ri tanlash uning silliq, muammosiz ishlashi uchun zarurdir. Fan, vosita va boshqa qo'zg'alish moslamalarini o'rnatishda aylanadigan komponentlarning hizalanishini ta'minlash uchun po'latdan yasalgan ramka yoki temir-beton taglik ishlatiladi. Ba'zan qo'llab-quvvatlash konstruktsiyasini tejashga urinish mashinaning tarkibiy qismlarining kerakli hizalanishini saqlab qolishning imkoni yo'qligiga olib keladi. Bu, ayniqsa, tebranish hizalanish o'zgarishlariga sezgir bo'lsa, ayniqsa, metall mahkamlagichlar bilan bog'langan alohida qismlardan iborat mashinalar uchun qabul qilinishi mumkin emas.
Baza yotqizilgan poydevor fan va vosita tebranishiga ham ta'sir qilishi mumkin. Agar poydevorning tabiiy chastotasi fan yoki motorning aylanish chastotasiga yaqin bo'lsa, fan ishlayotganda poydevor aks sado beradi. Buni poydevor, uning atrofidagi zamin va fan tayanchlari bo'ylab bir necha nuqtalarda tebranishlarni o'lchash orqali aniqlash mumkin. Ko'pincha rezonans sharoitida vertikal tebranish komponenti gorizontaldan sezilarli darajada oshadi. Poydevorni qattiqroq qilish yoki uning massasini oshirish orqali tebranishlarni susaytirish mumkin. Majburiy kuchlarni kamaytirishga imkon beradigan nomutanosiblik va noto'g'ri hizalanish bartaraf etilsa ham, sezilarli tebranish shartlari mavjud bo'lishi mumkin. Bu shuni anglatadiki, agar fan, uning qo'llab-quvvatlashi bilan birga, rezonansga yaqin bo'lsa, maqbul tebranish qiymatlariga erishish uchun odatda bunday mashinalar uchun talab qilinadiganidan ko'ra aniqroq muvozanat va milya tekislanishi talab qilinadi. Bu holat istalmagan va uni qo'llab-quvvatlash yoki beton blokning massasini va / yoki qattiqligini oshirish orqali oldini olish kerak.
Vibratsiya holatini kuzatish va diagnostika bo'yicha qo'llanma
Mashinaning tebranish holatini monitoring qilishning asosiy printsipi (bundan buyon matnda holat deb ataladi) tebranish darajasini oshirish tendentsiyasini aniqlash va uni yuzaga kelishi mumkin bo'lgan muammolar nuqtai nazaridan ko'rib chiqish uchun to'g'ri rejalashtirilgan o'lchovlar natijalarini kuzatishdan iborat. Monitoring zarar sekin rivojlanadigan va mexanizm holatining yomonlashishi o'lchanadigan jismoniy belgilar orqali namoyon bo'ladigan holatlarda qo'llaniladi.
Jismoniy nuqsonlarning rivojlanishi natijasida yuzaga keladigan fan tebranishini ma'lum vaqt oralig'ida kuzatish mumkin va tebranish darajasining oshishi aniqlanganda, kuzatish chastotasini oshirish va vaziyatni batafsil tahlil qilish mumkin. Bunday holda, tebranish chastotasini tahlil qilish asosida tebranish o'zgarishlarining sabablari aniqlanishi mumkin, bu esa zarur chora-tadbirlarni aniqlash va zarar jiddiy bo'lishidan ancha oldin ularni amalga oshirishni rejalashtirish imkonini beradi. Odatda, tebranish darajasi asosiy darajaga nisbatan 1,6 marta yoki 4 dB ga oshganda chora-tadbirlar zarur deb hisoblanadi.
Vaziyat monitoringi dasturi bir necha bosqichlardan iborat bo'lib, ularni qisqacha quyidagicha shakllantirish mumkin:
- a) fanning holatini aniqlang va asosiy tebranish darajasini aniqlang (u turli xil o'rnatish usullari va boshqalar tufayli zavod sinovlarida olingan darajadan farq qilishi mumkin);
- b) tebranishlarni o'lchash nuqtalarini tanlash;
- v) kuzatish (o'lchash) chastotasini aniqlash;
- d) axborotni ro'yxatga olish tartibini belgilaydi;
- e) fanning tebranish holatini baholash mezonlarini, mutlaq tebranish va tebranish o'zgarishlarining chegaraviy qiymatlarini aniqlash, shunga o'xshash mashinalarni ishlatish tajribasini umumlashtirish.
Ventilyatorlar odatda kritik darajaga yaqinlashmagan tezlikda hech qanday muammosiz ishlaganligi sababli, tebranish darajasi engil tezlik yoki yuk o'zgarishi bilan sezilarli darajada o'zgarmasligi kerak, ammo shuni ta'kidlash kerakki, fan o'zgaruvchan aylanish tezligi bilan ishlaganda, belgilangan tebranish chegarasi qiymatlari qo'llaniladi. maksimal ish aylanish tezligiga. Belgilangan tebranish chegarasida maksimal aylanish tezligiga erishib bo'lmasa, bu jiddiy muammo mavjudligini ko'rsatishi va maxsus tekshiruvni talab qilishi mumkin.
C ilovasida keltirilgan diagnostika bo'yicha ba'zi tavsiyalar fanning ishlash tajribasiga asoslanadi va tebranishning kuchayishi sabablarini tahlil qilishda ketma-ket qo'llash uchun mo'ljallangan.
Muayyan fanning tebranishini sifat jihatidan baholash va keyingi harakatlar uchun ko'rsatmalarni aniqlash uchun ISO 10816-1 tomonidan belgilangan tebranish holati zonasi chegaralaridan foydalanish mumkin.
Yangi muxlislar uchun ularning tebranish darajalari 3-jadvalda keltirilgan chegara qiymatlaridan past bo'lishi kutilmoqda. Bu qiymatlar ISO 10816-1 ga muvofiq tebranish holatining A zonasi chegarasiga to'g'ri keladi. Ogohlantirish va o'chirish darajalari uchun tavsiya etilgan qiymatlar fanatlarning muayyan turlari bo'yicha to'plangan ma'lumotlarni tahlil qilish asosida belgilanadi.
MUVOFIQ TAQIDA MA'LUMOT
USHBU STANDARTDA NORMATIV ISTANOMALAR OLARAK FOYDALANILGAN XALQARO STANDARTLAR
H.1-jadval
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Malumot davlatlararo standartining belgilanishi
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E'lon qilingan xalqaro standartning nomi va nomi va uning davlatlararo standartga muvofiqlik darajasining shartli belgilanishi
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GOST ISO 1940-1-2007
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ISO 1940-1: 1986. Tebranish. Qattiq rotorlarning muvozanatlash sifatiga qo'yiladigan talablar. 1-qism. Ruxsat etilgan nomutanosiblikni aniqlash (IDT)
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GOST ISO 5348-2002
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ISO 5348: 1999. Vibratsiya va zarba. Akselerometrlarni mexanik o'rnatish (IDT)
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GOST ISO 7919-1-2002
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ISO 7919-1: 1996. Pistonli bo'lmagan mashinalarning tebranishi. Aylanadigan vallar bo'yicha o'lchovlar va baholash mezonlari. 1-qism. Umumiy ko'rsatmalar (IDT)
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GOST ISO 10816-1-97
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ISO 10816-1: 1995. Tebranish. Aylanmaydigan qismlarda tebranish o'lchovlari bilan mashinaning holatini baholash. 1-qism. Umumiy ko'rsatmalar (IDT)
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GOST ISO 10816-3-2002
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ISO 10816-3: 1998. Tebranish. Aylanmaydigan qismlarda tebranish o'lchovlari bilan mashinaning holatini baholash. 3-qism. Nominal quvvati 15 kVt dan ortiq va nominal tezligi 120 dan 15000 rpm gacha bo'lgan sanoat mashinalari, in-situ o'lchovlari (IDT)
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GOST 10921-90
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ISO 5801: 1997. Sanoat muxlislari. Standartlashtirilgan kanallar yordamida ishlashni tekshirish (NEQ)
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GOST 19534-74
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ISO 1925: 2001. Tebranish. Balanslash. Lug'at (NEQ)
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GOST 24346-80
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ISO 2041: 1990. Vibratsiya va zarba. Lug'at (NEQ)
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GOST 31322-2006 (ISO 8821:1989)
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ISO 8821: 1989. Tebranish. Balanslash. Millar va o'rnatilgan qismlarni muvozanatlashda kalit yo'llarining ta'sirini hisobga olish bo'yicha ko'rsatmalar (MOD)
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GOST 31351-2007 (ISO 14695:2003)
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ISO 14695: 2003. Sanoat muxlislari. Vibratsiyani o'lchash usullari (MOD)
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Eslatma: Ushbu jadvalda standartning muvofiqlik darajasining quyidagi shartli belgilaridan foydalaniladi: IDT – bir xil standartlar;
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