Image: Welch
- Motor power
- 0.4 kW
- Weight
- 21 kg
Headline ratings converted to common units for comparison; the table below shows each figure exactly as published.
Technical data
Source: Welch product page · retrieved 2026-10-02| As published | 50 Hz | 50 Hz; @ 50 Hz | Without gas ballast partial | Without gas ballast total | With gas ballast total | Value | 50 Hz; (50 Hz) | 60 Hz |
|---|---|---|---|---|---|---|---|---|
| Free Air Displacement @ 50 Hz | ||||||||
| Pumping speed @ 50 Hz Pumping speed | ||||||||
| Ultimate Pressure Without gas ballast partial Ultimate pressure | ||||||||
| Ultimate Pressure Without gas ballast total Ultimate pressure | ||||||||
| Ultimate Pressure With gas ballast total Ultimate pressure | ||||||||
| Connection flanges | ||||||||
| Ambient temperature | ||||||||
| Noise Level (50 Hz) Noise level | ||||||||
| Oil Capacity | ||||||||
| Motor speed Speed | ||||||||
| Motor power | ||||||||
| Weight | ||||||||
| Series range: Ultimate Pressure |
Original extracted values are shown with their source and review status. Multiple values under the same condition remain separate for review.
R a min–max range as published, not a single rating
Explore the parts
CRVpro 4, pulled apart
This model’s parts, by where they sit
Our drawing of the machine type, with the CRVpro 4's own parts from Welch's lists. Side view along the shaft. Oil-free (dry) pumps have no exhaust box oil, sight glass or oil filter; their exhaust filter is a dust filter.
Reviewed operating performance · 60 Hz
Loading reviewed performance…
Service parts · 94
Seals and gaskets12
Rotating parts9
Fittings and hardware31
- Bottom flange705550
- Screw A2, M6x14822419-1
- Screw A2, M4x14822476
- U-Washer A2, 6.4x12.5x1.6824636
- Anti-Suck Back SpringS3016-99
- WasherS3029-99
- SpringS3044-99
- PinS3051-99
- ScrewS3052-99
- WasherS3055-99
- ScrewS3081-99
- ScrewS3083-99
- ScrewS3085-99
- ScrewS3086-99
- Elastic WasherS3087-99
- ScrewS3088-99
- ScrewS3089-99
- Elastic WasherS3092-99
- ScrewS3093-99
- ScrewS3094-99
- Blank FlangeS3098-99
- ScrewS3100-99
- Elastic WasherS3101-99
- WasherS3102-99
- Flat KeyS3106-99
- ScrewS3107-99
- Elastic WasherS3114-99
- Flat WasherS3115-99
- ScrewS3117-99
- ScrewS3118-99
- Flat WasherS3120-99
Valves8
Housing and covers8
Piston and diaphragm parts1
Other parts16
Part numbers from Welch’s parts lists, shop and instruction manuals. Open a part for its other models, replacements and suppliers.
Parts diagrams
Exploded views from Welch’s own documents, with each position and part number as printed. Select a part to see what it fits, who sells it and what replaces it.
Exploded view · operation manual crv pro 4 6 8, page 1688 positions
The positions on this drawing haven’t been placed yet: choose a position in the list for its part. Drag to move, pinch or Ctrl + scroll to zoom.
Select a part on the drawing or in the list to see its number, what it fits and where to get it. Turn on “select several” to build one quote for many parts.
| Pos. | Part number | Description | Qty |
|---|---|---|---|
| 800200 | Molecular sieve (sorption agent 1l) | ||
| S3001-99 | Motor | ||
| 705549 | Wire mesh | ||
| S3081-99 | Screw | ||
| 705548-06 | Clamping cover | ||
| 829290 | O-ring FKM, 84x3 | ||
| S3002-99 | Handle | ||
| 822419-1 | Screw A2, M6x14 | ||
| S3083-99 | Screw | ||
| 824636 | U-Washer A2, 6.4x12.5x1.6 | ||
| 705550 | Bottom flange | ||
| S3085-99 | Screw | ||
| 822476 | Screw A2, M4x14 | ||
| S3003-99 | Coupling | ||
| S3004-99 | Red Strip | ||
| S3086-99 | Screw | ||
| S3005-99 | Side Overlay | ||
| S3006-99 | Trestle | ||
| S3007-99 | Base | ||
| S3008-99 | Foot Pad | ||
| S3087-99 | Elastic Washer | ||
| S3088-99 | Screw | ||
| S3009-99 | Felt | ||
| S3010-99 | O-Ring | ||
| S3011-99 | Gas Ballast Valve Bush | ||
| S3012-99 | Gas Ballast Valve Rod | ||
| S3013-99 | Gas Ballast Location Bush | ||
| S3014-99 | Gas Ballast Valve Ring | ||
| S3089-99 | Screw | ||
| S3015-99 | Gas Ballast Knob | ||
| S3092-99 | Elastic Washer | ||
| S3093-99 | Screw | ||
| S3016-99 | Anti-Suck Back Spring | ||
| S3017-99 | Anti-Suck Back Piston | ||
| S3019-99 | Oil Seal | ||
| S3020-99 | Anti-Suck Back Cover | ||
| S3021-99 | Anti-Suck Back Plate | ||
| S3022-99 | O-Ring | ||
| S3023-99 | Inlet Port | ||
| S3094-99 | Screw | ||
| S3095-99 | Filter | ||
| S3096-99 | O-Ring | ||
| S3097-99 | Rubber Sheet | ||
| S3098-99 | Blank Flange | ||
| S3099-99 | Hoop | ||
| S3102-99 | Washer | ||
| S3024-99 | Coupling Element | ||
| S3025-99 | Coupling | ||
| S3100-99 | Screw | ||
| S3101-99 | Elastic Washer | ||
| S3026-99 | Pump Cover | ||
| S3027-99 | Oil Seal | ||
| S3028-99 | O-Ring | ||
| S3029-99 | Washer | ||
| S3030-99 | O-Ring | ||
| S3031-99 | Bush | ||
| S3032-99 | Oil Pump Rotor(Out) | ||
| S3033-99 | Oil Pump Rotor(In) | ||
| S3034-99 | Gasket | ||
| S3035-99 | Fore Stator | ||
| S3036-99 | Oil Seal | ||
| S3037-99 | Fore Rotor | ||
| S3038-99 | Fore Vane | ||
| S3106-99 | Flat Key | ||
| S3107-99 | Screw | ||
| S3040-99 | Oil-Proofing Cover | ||
| S3109-99 | Filter | ||
| S3041-99 | Limiting Plate | ||
| S3042-99 | Exhaust Valve Plate | ||
| S3043-99 | Back Pump Vane | ||
| S3044-99 | Spring | ||
| S3045-99 | Gas Ballast Valve Head | ||
| S3046-99 | Rear Rotor | ||
| S3048-99 | Rear Vane | ||
| S3049-99 | Oil Pump Valve | ||
| S3050-99 | Rear Cover | ||
| S3051-99 | Pin | ||
| S3052-99 | Screw | ||
| S3114-99 | Elastic Washer | ||
| S3115-99 | Flat Washer | ||
| S3053-99 | Flap | ||
| S3116-99 | Centre Rest | ||
| S3054-99 | Exhaust Port | ||
| S3055-99 | Washer | ||
| S3056-99 | Oil Fill Plug | ||
| S3058-99 | Oil Casing | ||
| S3059-99 | O-Ring | ||
| S3060-99 | Glass | ||
| S3061-99 | Oil Window | ||
| S3117-99 | Screw | ||
| S3062-99 | Oil Drain Plug | ||
| S3063-99 | O-Ring | ||
| S3118-99 | Screw | ||
| S3120-99 | Flat Washer |
Positions and part numbers as printed in Welch’s operation manual crv pro 4 6 8, page 16 · view the source document