Dive compressor Mark III Silent

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Overview
The Mark III Silent is a breathing-air compressor from Coltri's Efficient Line. It combines a 3-stage high-pressure pumping unit, a Maxifilter purification system and a silenced cab chassis designed for maintenance access and low noise emission. The unit is intended for diving, industrial and emergency breathing-air supply where quiet, continuous operation and regulated air quality are required.

Pumping unit - key components

• 3-stage high-pressure pumping unit
• Aluminum monoblock
• Forged steel gooseneck
• Flutter (splash) lubrication
• Forged aluminum connecting rods
• Bench roller bearings
• Connecting-rod roller bearings
• 1st and 2nd stage cylinders in aluminum with hard Nicasil coating
• Skid-guide cylinders of 2nd and 3rd stages in aluminum with hard Nicasil coating
• 3rd stage cylinder in treated special steel
• Stainless steel intake and exhaust valves
• Stainless steel interstage cooling tubes
• Separators after the 2nd and 3rd stages
• Safety valves after each stage
• Oil level sensor

Electric motor
Available with single-phase or three-phase electric motor, power range 4–5.5 kW. Motion is transferred to the pumping unit via a belt drive with a tilting motor carrier plate to maintain belt tension.

Purification system - Maxifilter
The Maxifilter purification system uses combined molecular sieve and activated carbon cartridges to remove moisture, oil vapours and contaminants when original cartridges are installed. It is positioned after the 2nd and 3rd stage separators and before the pressure-holding valve to create a primary barrier against moisture. Filter capacity (inlet air at 20°C and 200 bar): 890 m³.

Electrical cabinet - features

• ON/OFF switch with motor protection
• Electromechanical pressure switch to stop the compressor at final pressure
• Drainage of all separators between stages and of the final separator during operation
• Timer for automatic condensate drain device
• Integrated no-load start (automatic discharge at each shutdown)
• Condensate collection tank: 5 L with silencer (operative capacity ≈ 3 L) for compliant disposal
• Interstage pressure gauges showing operating pressure for each compression stage (for valve tightness checks and diagnostics)

Frame and maintenance
Silenced cab chassis designed for easy maintenance. External oil level and drain indication. Control console equipped with interstage gauges, internal temperature indicator, presence and phase-sequence alarm, oil shortage alarm, run/stop and manual condensate drain controls.

Standard equipment

• 2 cylinder connections (choice of DIN 232, DIN 300 or INT/YOKE 232 bar)
• 2 filling hoses 1.2 m long
• Pressure holding valve
• Interstage control manometers
• Filter system Maxifilter (original cartridges recommended)
• Inside-cabin temperature monitoring with automatic shutdown
• Automatic rotation direction control
• Pressure switch with automatic shutdown
• Oil level control with automatic shutdown
• Automatic condensate drain with conveying system into the canister
• Frame color: Black RAL 9005

Application & performance notes
The unit is designed to produce breathing air that meets applicable standards when original filter cartridges are used and the system is configured properly. The combination of a 3-stage pump, interstage separators, Maxifilter and safety devices supports high air quality, operational continuity and simplified maintenance.

Technical specifications

• Model: Mark III Silent
• Brand: Coltri
• Pumping unit: 3-stage high-pressure unit (aluminum monoblock; 1st/2nd stage aluminum cylinders with hard Nicasil coating; 3rd stage treated special steel)
• Motor power: single-phase or three-phase motor, 4 ÷ 5.5 kW
• Purification: Maxifilter (molecular sieve + activated carbon)
• Maxifilter capacity: 890 m³ (inlet air 20°C, 200 bar)
• Condensate collection tank: 5 L (approx. 3 L usable) with silencer
• Standard cylinder connection options: DIN 232, DIN 300, INT/YOKE 232 bar
• Included hoses: 2 × 1.2 m filling hoses
• Safety: safety valves after each stage; interstage pressure gauges; oil level sensor and automatic shutdowns (oil level, pressure, temperature)
• Frame: silenced cab chassis; tilting motor carrier plate; frame color Black (RAL 9005)