GRINO ROTAMIK SKS 475 2V vs Elektror 2SD720-50/5,5 Comparison

Both are 5.5kW two-stage side channel blowers (ปราศจากน้ำมัน) with identical operating point: -470 เอ็มบาร์, 312 ลบ.ม./ชม. They can replace each other, but there are significant differences in brand, internal structural details, มอเตอร์, housings, performance curves and spare parts supply.

1. ข้อมูลพื้นฐาน

GRINO ROTAMIK SKS 475 2V PDF: Spanish brand, SKS series. 2V = 2-stage; 5.5กิโลวัตต์; operating condition: 312 m³/h @ -470 เอ็มบาร์; maximum vacuum -500 เอ็มบาร์

Elektror 2SD720-50/5,5 PDF: German Elektror. 2SD = two-stage side channel; 5.5กิโลวัตต์; operating condition approx. 312 m³/h @ -470 เอ็มบาร์; ultimate vacuum up to -500 เอ็มบาร์

1. ความแตกต่างหลัก
2. ยี่ห้อ & ต้นทาง

SKS475 2V: Griño Rotamik from Spain, mid-range European side channel pump. Widely used in vacuum handling and pneumatic conveying, but limited agent network within China.

2SD720-50/5.5: German Elektror, premium side channel blower. Extensively adopted for industrial equipment and OEM applications, with mature spare parts support in China.

2. ใบพัด & Flow Path Structure

SKS475 2V: Two-stage back-to-back impeller layout. Split aluminium housing with closed-type impeller blades. Single-stage variant SKS475 (without 2V suffix) has free air flow up to 552 ลบ.ม./ชม.

2SD720-50/5.5: Two-stage side channel chambers arranged in series. Open impeller design with robust one-piece cast housing. Larger models in the 2SD series can reach ultimate vacuum up to -750 เอ็มบาร์.

3. Motor Specifications

SKS475 2V: IE2 motor, IP54, Class F insulation. Built-in thermal protection as standard; silencer supplied separately (not factory fitted).

2SD720-50/5,5: IE3 high-efficiency motor, IP54, Class F insulation. Integrated inlet/outlet silencers. Factory fitted motor winding temperature sensor for direct PLC thermal protection signal connection.

4. เสียงรบกวน & น้ำหนัก

SKS475 2V: 74~78 dB(ก), ประมาณ. 72 กก

2SD720-50/5.5: 71~76 dB(ก), heavier with thicker housing, better low-frequency noise attenuation.

5. Performance Curve Characteristics (กุญแจสำคัญสำหรับการเลือก)

SKS475 2V: Steep curve within -400 ~ -480 เอ็มบาร์. Flow drops sharply once vacuum exceeds -480 เอ็มบาร์. Suitable for stable vacuum conditions; not recommended for prolonged operation near ultimate vacuum.

2SD720-50/5.5: Gentle performance curve with higher overload margin. Stable under short-term vacuum spikes and pressure fluctuations; permits temporary operation close to ultimate vacuum.

6. การติดตั้ง & Connection Dimensions

SKS475 2V: DN65 (2.5″) inlet/outlet. Spanish standard base mounting holes, incompatible with Elektror. Direct in-situ replacement requires base and pipework modification.

2SD720-50/5.5: DN65 inlet/outlet with different flange thread specification. German standard base footprint, not interchangeable with SKS475 2V.

7. การซ่อมบำรุง & อะไหล่

SKS475 2V: Limited local stock in China, long lead times. ตลับลูกปืน, impellers and components require import ordering.

2SD720-50/5,5: Local agents stock common wear parts (ตลับลูกปืน, แมวน้ำ, ตัวกรอง, silencer inserts) with faster after-sales response.

8. ช่วงราคา

Procurement cost of SKS475 2V is generally lower than Elektror 2SD720-50/5,5.

III. Application Selection Guidance

✅ Choose SKS475 2V

ลำดับความสำคัญของงบประมาณ; stable vacuum without frequent spikes near ultimate vacuum; equipment exported to Spain / Southern Europe; existing plant using GRINO with established spare part system.

✅ Choose 2SD720-50/5.5

Large vacuum fluctuations, frequent start-stop cycles; stricter noise requirements; on-site service and fast spare parts required in China; continuous 24-hour operation; IE3 high-efficiency motor required plus PLC integrated winding temperature protection.

1. คุณสมบัติทั่วไป

Both are oil-free dry-running side channel blowers, no oil lubrication required.

Suitable for vacuum gripping, vacuum handling and powder conveying.

Both support variable frequency speed regulation.

Medium must be clean dry air; inlet filter is mandatory.

1. Replacement Risk Warning

Even though the operating point parameters fully match (312 m³/h @ -470 เอ็มบาร์), base mounting holes and nozzle flanges are not interchangeable. New base plate and pipe adapters must be fabricated for replacement.

GRINO ROTAMIK SKS 475 2V vs Elektror 2SD720-50/5,5 Outline Dimension Table

หน่วย: มม, DN65 connection, 5.5kW two-stage side channel blower

Key Mounting Replacement Notes

1. Pipe nozzles: DN65 nominal diameter for both, custom adapter required to convert external thread to flange connection;
2. Base plate: Mismatched centre height and foot print. Reuse of original base is impossible; new steel base or frame modification required;
3. Space clearance: 2SD720 is longer and taller. Verify internal equipment clearance to avoid mechanical interference;
4. Pipework: SKS475 2V has no built-in silencer. After switching to 2SD720, remove old external silencer to reduce line pressure loss.

GRINO SKS475 2V → Elektror 2SD720-50/5,5 On-site Retrofit Checklist

แอปพลิเคชัน: Replace existing SKS475 2V with 2SD720-50/5,5; 5.5kW two-stage vacuum side channel blower, working point -470 เอ็มบาร์, 312 ลบ.ม./ชม

1. Installation Space Verification

Overall length: Old SKS475 2V ≈615 mm; new 2SD720≈650 mm, +35 mm longer. Check interference at motor rear side

ความสูงโดยรวม: Old ≈430 mm; new ≈445 mm, +15 mm taller. Check clearance above for pipework/guard/cable clash

Overall width: Old ≈370 mm; new ≈385 mm, +15 มม. กว้างขึ้น. Confirm side maintenance access

Lifting space: New unit 7 kg heavier (79 กก). Verify lifting point and hoist capacity

Maintenance access: Terminal box on motor top. Confirm space for wiring and PT100 connector access

1. ฐาน & Foundation Modification

Centre height difference: เก่า 220 mm vs new 230 มม (+10 มม). Two options: add shim plates or fabricate new base

Foot hole pitch: Old 420×260 vs new 445×275. Original base cannot be reused

Base plate material: นาที. 10 mm steel plate with anti-corrosion coating; levelling shims recommended

Foundation bolts: Both M12. Check plate strength and anchor bolt capacity; rubber anti-vibration pads recommended to reduce vibration transmission

Level check: Level blower after installation to prevent impeller rubbing and premature bearing failure

III. Pipework & Nozzle Retrofit (DN65)

ประเภทการเชื่อมต่อ: SKS 2.5″ male thread vs 2SD720 flange thread, custom transition adapter required

Pipe routing: New blower has integrated silencers. Remove old external silencer to shorten piping and reduce pressure drop

กรอง: Reuse existing inlet filter, verify DN65 fit, replace all gaskets

Non-return valve / vacuum gauge: Retain mounting location, check adapter sealing. Air leakage directly reduces vacuum level

Flexible bellows: Flexible vibration isolators must be fitted at both inlet and outlet to isolate vibration; prevent pipe stress loading on blower casing

Pipe supports: Pipe weight must not rest on blower ports. Independent pipe supports required

1. Electrical Modification

Motor rating: Both 5.5kW with similar rated current. Existing circuit breaker and contactor are theoretically usable, but recheck rating

Motor insulation / การป้องกัน: SKS IE2; 2SD720 IE3 with built-in PT100 winding temperature sensor

Temperature wiring: Add PT100 signal cable to PLC / โมดูลอุณหภูมิ; configure high-temperature alarm and trip logic

Terminal box location: New terminal box on motor top. Redesign cable routing, check cable length to avoid tension

Cable sizing: Existing ≥4 mm² copper power cable can be reused. Verify terminals and reliable PE protective earth connection

วีเอฟดี (ถ้าติดตั้ง):

Re-enter motor nameplate parameters into VFD (จัดอันดับปัจจุบัน, ความเร็ว, พลัง)

Adjust carrier frequency to reduce motor noise

Set overload and stall protection

1. Vacuum Control & Process Protection

Operating point: เป้า -470 mbar @312 m³/h. New model has flatter curve with improved vacuum fluctuation performance

Vacuum transmitter: Reuse existing sensor, re-calibrate zero point

Interlock logic review:

Low vacuum alarm (ป้องกันการรั่วไหล)

Over-limit vacuum protection (anti-overload)

Motor high temperature alarm and shutdown

การควบคุมลำดับ: Open inlet valve → start blower; stop blower only after pressure relief to avoid vacuum shock

1. Pre-commissioning Inspection

Manual turning: Rotate impeller with power disconnected. No binding or rubbing noise

รัด: Tighten base and pipe fittings to specified torque

ซีล: Replace all gaskets, apply suitable sealant to threads/flanges

Filter inspection: Check filter element; replace if contaminated

การต่อสายดิน: Confirm reliable protective earth connection

No-load trial run: บายพาส / release load, run 3~5 minutes. Check noise, temperature rise and vibration

ปกเกล้าเจ้าอยู่หัว. Commissioning Acceptance Tests

Measure no-load current, compare against motor nameplate

Close loop, adjust to target operating point: -470 เอ็มบาร์, record actual flow rate

Vibration measurement: Record housing vibration values against acceptance criteria

Noise inspection: Confirm no abnormal sharp noise

Temperature rise: Continuous run 1~2 hours, monitor winding temperature

Leakage test: Pressure hold test, confirm zero pipe air leakage

8. อะไหล่ & Maintenance Update

Update spare parts list to Elektror OEM bearings, seals and silencer inserts

ช่วงเวลาการบำรุงรักษา: Both oil-free dry type. Regular inlet filter cleaning; bearing service life approx. 20000 ชม.

Alarm system: Add PT100 high temperature alarm and HMI alarm message

⚠️ High Risk Reminders

1. Air leakage in vacuum system is the most common fault. All joint sealing must be carefully inspected, otherwise target -470 mbar cannot be achieved;
2. Do not rigidly couple pipework. Flexible joints are mandatory; pipe stress can crack blower housing;
3. Do not simply enlarge original base holes for fitting. Long-term vibration will shorten bearing life;
4. If original external silencer is not removed after retrofit, extra pressure loss will reduce flow performance.
5. Elektror 2SD Two-Stage Side Channel Blower Series (2SD720-50/5,5 belongs to this series)

Naming rule: 2SD frame size 50 / กำลังมอเตอร์; 2SD = two-stage, 50 = 50Hz, power in kW. All models with integrated silencer + PT100 motor temperature sensor, oil-free dry-running, ultimate vacuum up to -750 mbar for larger frames.

Full Frame List

1. 2SD220 (small frame)

2SD220-50/0,55

2SD220-50/0,75

2SD220-50/1,1

2SD220-50/1,5

2SD220-50/2,2

2. 2SD320

2SD320-50/1,5

2SD320-50/2,2

2SD320-50/3,0

2SD320-50/4,0

3. 2SD520

2SD520-50/2,2

2SD520-50/3,0

2SD520-50/4,0

2SD520-50/5,5

2SD520-50/7,5

4. 2SD720 (replacement model for this project)

2SD720-50/4,0

2SD720-50/5,5 (target model)

2SD720-50/7,5

5. 2SD740 (alternative frame with same power)

2SD740-50/4,0

2SD740-50/5,5

2SD740-50/7,5

6. 2SD820

2SD820-50/7,5

2SD820-50/11,0

2SD820-50/15,0

7. 2SD840

2SD840-50/8,5

2SD840-50/11,0

2SD840-50/15,0

8. 2SD920 (largest frame)

2SD920-50/11,0

2SD920-50/16,5

2SD920-50/20,0

2SD920-50/25,0

บันทึก: 60Hz versions available (replace 50 กับ 60 for overseas projects). All models VFD compatible. Same frame size shares identical chamber/impeller; only motor differs for different power ratings.

1. GRINO ROTAMIK SKS Series (Original SKS475 2V belongs to this series)

SKS: side channel vortex pump; 2V = Two-Stage. Suffix without 2V = single-stage SKH/SKS; T1.B for 400V three-phase version

SKS Two-Stage (2วี) รายการรุ่น

SKS80 2V

SKS156 2V

SKS250 2V

SKS370 2V

SKS475 2V (existing equipment)

SKS570 2V

SKS750 2V

SKS Single-Stage Models (SKH / SKS, max vacuum approx. -400 เอ็มบาร์, insufficient for -470 เอ็มบาร์)

SKS80

SKS140

SKS156

SKS250

SKS370

SKS475 (single stage, no 2V suffix, not a valid replacement for two-stage unit)

SKS570

SKS750

III. Quick Selection Guidance

1. Elektror 2SD: All 2SD models are two-stage, suitable for high vacuum >450 mbar absolute vacuum. Single-stage Elektror models designated SD/1SD, do not mix up.
2. GRINO SKS: Must carry suffix 2V for two-stage version. Models without 2V are single-stage with insufficient vacuum for -470 mbar application.
3. Operating Point Quick Reference (Your Working Condition)

หน่วยเดิม: SKS475 2V, 5.5กิโลวัตต์, 312 m³/h @ -470 เอ็มบาร์

Matching Elektror model: 2SD720-50/5,5; alternative option: 2SD740-50/5,5 (slightly different performance curve)