Heavy Duty Zero Pressure Accumulator, Roach Model SZ251ZPA Smart Zone™

Roach Model SZ251ZPA Conveyor with Smart Zone® is a heavy duty zero pressure accumulator, designed to accumulate heavy products, containers and pallets in 5’ zones

TYPE: Accumulation Conveyors

MODEL: Roach SZ251ZPA Smart Zone™

Zero Pressure Live Roller Accumulation Conveyor with SMART ZONE photoeye sensors for heavy duty accumulation applications .

The most common type of zero pressure conveyors use rollers to transport  containers while using a retro-reflective photo eye to accumulate the products into zones.  The first box travels down the conveyor and stops at the last photo-eye.  The next box comes down the conveyor and stops at the previous photo-eye, not touching the first box, hence the term zero-pressure. This is very important when trying to convey various sizes and weights of product as the boxes should not come into contact with each other.


  • Designed to accumulate heavy products, containers and pallets in 5' zones
  • Design incorporates photo electric sensors, instead of sensor rollers, eliminating issues commonly found with conveying wooden pallets
  • Products DO NOT touch during accumulation and are singulated individually off of the conveyor
  • Up to 3000 lbs may be safely accumulated


  • Package handling
  • Carton transporting
  • Converting plants
  • Manufacturing 
  • Distribution


  • Tread Rollers: 2-1/2” dia. x 11 ga. steel, model 251S.
  • Pressure Rollers: 1.9” dia. x 16 ga. steel, model 196S; 27” BF for all widths.
  • Return Rollers: 1.9” dia. x 16 ga. steel, model 196S, adjustable.
  • Belting: 24” wide PVC-120 COS
  • Side Mount End Drive: Allows one direction unit operation.
  • Drive Pulley: 12” dia., with 1-15/16” dia. shaft, crowned and fully lagged.
  • Tail Pulley: 8” dia., crowned, with 1-3/16” dia. shaft.
  • Take Up: Screw type unit at tail pulley provides 12” belt take-up.
  • Bearings Precision ABEC bearings.
  • Bed: 5” x 1-1/2” x 3/16” formed steel channel frame slotted for tread rollers to pop-out. When unit is installed at 7’-0” elevation or higher, rollers must be retained in conveyor. Specify desired elevation. Bed sections are bolted together with butt couplings and floor supports.
  • Speed: 35 FPM, constant.
  • Accumulation: 5’-0” long zones with zone singulation operation. 1’-6” of live roller over end plates at each end of conveyor remains “live” during operation (# of zones x zone length + 3’-0” = overall conveyor length). Zones are pneumatically actuated by using photo electric sensors.
  • FRL: Unit is provided with filter, regulator and lubricator with 3/8” ports for 60 PSI operational pressure.
  • Motor Drive: 1 HP, 230/460/3, 60 cycle, ODP right angle gear motor.
  • Roller Chain: No. 60 chain provided at drive pulley. Chain take-up provided on motor base.


  • Belting: 12” wide PVC-120; 24” wide PVC-150.
  • Drive Pulley: 8” dia. with 1-7/16” dia. shaft, crowned and fully lagged.
  • Slug Release: Products may be slug released rather than individual product release in normal zone singulation; accumulation mode will not be disturbed when slug release option utilized.
  • Floor Supports: Supports, knee brac-es, casters and polytier supports available. See Conveyor Accessories.
  • Speed: Constant speed 8-120 FPM; DC variable speed; AC inverter variable speed. Other constant or variable speeds available. NOTE: Capacity changes with speed.
  • Motors: Available through 3 HP in TEFC, explosion proof, dirty duty, brake motor, 115/230/1, 575/3, etc.
  • Electrical Controls: Magnetic starter; One direction manual starter; Momentary start/stop push button station; start/stop push button station.
  • Defused SmartZone: Photo eyes mounted below tread rollers.

For more information on the Model SZ251ZPA Heavy Duty Zero Pressure Accumulator SmartZone™ Conveyorplease contact a Thomas Conveyor & Equipment Automation Engineer at 844 220 0086 or click on the Contact Us button above.

QUESTIONS? CALL 844-220-0086