Overview
Every conventional VRC — hydraulic or mechanical — uses chains, cables, sheaves, sprockets, or bearings somewhere in the lifting system. Each of those components can wear, stretch, break, or require lubrication. The PFlow D Series eliminates all of them. Its Dual-Pak design uses two direct-acting hydraulic cylinders that raise and lower the carriage without any intermediate drivetrain components. The cylinders do the work. Nothing else is in the load path.
For mezzanine and balcony applications where loads are moderate and the priority is years of reliable operation with minimal service, the D Series is the simplest hydraulic VRC available.
Dual-Pak Direct-Action Design
The D Series carriage is lifted and lowered by dual 2-inch direct-acting hydraulic cylinders mounted between 6-inch structural steel guide columns. An ultra-high molecular weight polyethylene cylinder guide prevents the cylinders from twisting during operation, extending cylinder life. A pressure-compensated control valve regulates hydraulic oil flow for constant lowering speed under any load — the carriage descends at the same controlled rate whether it is empty or fully loaded.
Because there are no chains, cables, sheaves, sprockets, or bearings in the lifting system, the D Series requires no drivetrain lubrication and has no drivetrain components that can wear or fail.
Specifications
- Capacity: up to 3,000 lbs (based on carriage size)
- Carriage: up to 6 ft wide x 6 ft long
- Configuration: cantilever
- Vertical rise: up to 15 ft
- Speed: 17 fpm standard, up to 25 fpm available
- Cycle rate: 10 cycles per hour, 100 per day
- Environment: indoor or outdoor
- Warranty: lifetime structural warranty
- Compliance: ASME B20.1 Safety Standards
Safety Features
- Mechanical stops ensure positive carriage leveling with the upper deck and prevent overtravel
- Pressure switch prevents drifting or sinking for stable loading and unloading
- Velocity fuses prevent uncontrolled descent if a hose ruptures
- Check valves hold the carriage in place during power loss
- Manual lowering valve for emergency descent
Installation and Options
The remote-mounted control panel and hydraulic pump are pre-wired and ready for immediate installation. Optional quick-connect cabling reduces field wiring costs. For outdoor or wash-down environments, optional hot-dipped galvanized or epoxy finishes are available. Explosion-proof components can be specified for classified (hazardous) environments.
Applications
The D Series is purpose-built for mezzanine and balcony transfers where simplicity, low maintenance, and reliability are the top priorities. It serves warehouses, retail stockrooms, archives, self-storage, light manufacturing, and any two-level indoor or outdoor application where loads stay within 3,000 lbs and vertical rise is 15 feet or less.
D Series vs. 21 Series
Both are PFlow hydraulic VRCs with lifetime structural warranties. The D Series uses direct-acting cylinders with no chains or cables for maximum simplicity and minimum maintenance. The 21 Series uses chain-over-sprocket actuation with a synchronized torsion bar for higher capacity (up to 6,000 lbs), larger carriages (up to 12′ x 10′), and greater rise (up to 22 ft). Choose the D Series when simplicity and low maintenance are the priority. Choose the 21 Series when capacity, carriage size, or lift height exceed D Series limits.