Hog Restrainer Requirements & Definitions

• This standard specifies the requirements for a hog restrainer.
• The word "shall" indicates mandatory requirements.
• The word "should" indicates a recommendation among possibilities.

Definitions

• Counterweight is a piece of mass with a weight nearly equal to the entrance gate, attached to a cable that acts as an operating lever.
• Counterweight guide keeps the counterweight in its line of motion.
• Discharge wall is part of the restrainer that can be tilted to release the hog after stunning.
• Drop floor is the flooring of the hog restrainer designed to suspend the hog during disengagement.
• Drop floor lever resets the drop floor.
• Dump lever opens the dumping side wall to release the hog.
• Entrance gate allows livestock access into the restrainer.
• False floor is a solid floor at the bottom of the restrainer for animals to walk down to the entrance ramp.
• Floor lock keeps the drop floor in its locked position.
• Hydraulic cylinder is a device used to give linear force using hydraulic fluid under pressure.
• Pneumatic cylinder is a device that produces force, often with movement, powered by compressed gas, typically air.
• Restrainer is a slaughterhouse equipment used to secure and restrict the animal's body movements in an upright position before stunning
• Stroke refers to the length of displacement of the cylinder rod
• Stunner renders the animal unconscious prior to sticking and bleeding
• Stunning is the process of rendering an animal unconscious before sticking and bleeding.

Classification of Hog Restrainers

• Manually operated restrainers have a dump lever.
• Semi-automatic restrainers use compressed fluid to actuate discharge wall movements via cylinder actuation, and can be:
  • Hydraulic type, using pressurized hydraulic fluid (oil or water).
  • Pneumatic type, using compressed gas (air).
• Automatic restrainers use a conveyor system to move, restrain, stun, and dump the animal.

Principle of Operation

• Hog restrainers secure the hog with minimal stress prior to humane stunning.

Manually Operated Restrainers

• The entrance gate is opened by lowering the gate's counterweight to slide the gate upward
• After the hog enters, the entrance gate is closed to secure it
• Releasing the floor lock disengages the drop floor, suspending the hog on the walls
• The operator then stuns the hog through the top access and tilts the discharge wall to release the hog

Semi-Automatic Restrainers

• Operate on the same principles as manual types but use a hydraulic or pneumatic cylinder to tilt the discharge wall

Automatic Restrainers

• Carry the hog into a conveyor system for stunning, then dump it out at the conveyor's end

Fabrication Requirements: Manually Operated

• Shall consist of the following: entrance gate, counterweight, counterweight guide, drop floor, drop floor lever, floor lock, discharge wall, and a dump lever
• Must have an open top for stunning and an opened side for the discharge wall
• Walls should have smooth surfaces and rounded edges or corners
• Mud guards are installed on top to prevent operator electrocution.
• The entrance gate should have a frame assembly for counterweight to guide motion.
• The restrainer should hold the hog upright after stunning

Fabrication Requirements: Additional Considerations for Manual Restrainers

• The vertical entrance gate is connected to the counterweight by a cable through pulleys
• The vertical entrance gate should have a rubber pad to reduce impact during closing
• The drop floor should have rubber pads underneath.
• Moving parts should have grease points for lubrication.
• The dump lever should have a safety lock.
• The drop floor should have non-slip flooring.
• Framing and major parts should be constructed from bent stainless steel (304 or higher) or non-corrosive steel plates.
• The counterweight should be made of non-corrosive steel or concrete

Fabrication Requirements: Semi-Automatic Restrainers

• Consist of the same components as manual restrainers, but replace the dump lever with actuating cylinders
• Pressure gauges (10 bars, ≥70 mm diameter) should be installed near the flow valve
• Silencers should be installed
• Other parts use bent stainless steel plates (e.g., 304 or higher) or non-corrosive steel plates.
• The counterweight should be non-corrosive steel or concrete

Fabrication Requirements: Automatic Restrainers

• Conveyor shall have no sharp edges
• The conveyor shall secure the hog
• Walls should be adjustable for different sized hogs
• A solid hold-down rack should be attached on top.
• A solid false floor should be underneath the conveyor to eliminate "visual cliff effect"
• The entrance ramp should be non-slip and sloping downward.
• Stainless steel (e.g., 304 or higher) or non-corrosive steel should be used

Fabrication Requirements: Welding

• All welded parts should be watertight and smoothly polished, and pass visual inspection (AWS D1.1:2000)
• There shall be no cracks and fusion between layers of weld metal.
• All craters filled, weld profiles acceptable
• Welded joints should be at least 4mm fillet weld.
• Undercut should not exceed 2mm (1/16 inch).

Performance Requirements

• The hog restrainer should perform sanitary operation and comply with GMP, SSOP, and HACCP
• Hog restrainer noise limited to 96dBA for four hours of continuous operation

Manually Operated Performance

• Lowering the dump lever shall tilt the discharge wall
• Restrainer shall hold the hog without stress.

Semi-Automatic Performance

• Pressure from the pump/compressor shall tilt the discharge wall and restore it
• Operating pressure of the hog restrainer should comply with the fabricator's specifications.
• The cylinder shall maintain the discharge wall in any position
• The discharge wall should tilt when dumping and return upright
• The cylinder should function normally with a hog

Automatic Performance

• The conveyor belt should carry and secure the hog.
• Conveyor speed commensurate to restrain length.

Safety, Workmanship, and Finish

• The restrainer should be free from manufacturing defects
• The surface of hog restrainer should not be painted
• Parts touching the hog should have smooth edges
• The restrainer shall have insulation to use electric stunner

Warranty

• Construction should be durable without breakdown for one year from purchase
• Warranty for parts and services provided for one year after installation.

Maintenance and Operation

• An operator's manual (PAES 102 compliant) shall be provided for local fabricators
• Grease points for axle lubrication should be provided, use food grade

Testing

• Testing of the hog restrainer shall be conducted on-site and in accordance with PAES 502.

Marking and Labeling

• In English, using a plate or stencil:
  • Brand name/trademark (optional)
  • Model/serial number
  • Maximum weight capacity
  • Fabricator information
  • Country of manufacture
• Safety/precautionary markings in English/Filipino, printed in red with white background.
• Should have a durable coating surface and be waterproof should not fade, discolor or crack.