9.1        Important Note

  • The comments in this chapter are only provided to highlight common safety hazards of working with the filter press, chemicals, and other equipment. Complete operation and safety information will be found in the appropriate OEM manuals and MSDS sheets.
  • The OEM manuals and MSDS are considered authoritative and final. The comments in this section are only a brief introduction and guide to very common safety issues.  It is the responsibility of the technician to review the manuals and MSDS sheets.
  • Where plant safety rules are more stringent, they must be obeyed.

9.2       Filter Press

9.2.1    General

  • Make sure the filter press is properly closed to the correct pressure, that the plates and cloths are properly aligned to prevent excessive leakage.
  • Make sure all pipe fittings and connections are tightened properly
  • When running the membrane press, make sure that the compressed gas cylinder can be isolated and that the membranes can be safely vented.

9.2.2   Recessed Chamber

  • Make sure the filter press hydraulics are pumped to the correct closing pressure for the specific unit used.
  • Make sure the locking ring tight before feeding the press
  • Do not exceed 225 psig on the HPL300, HPL470, and HPL500
  • If filtering hot liquids (180 – 200 F) the maximum pressure is 100 psig
  • Do not exceed 100 psig on the Bench Press
  • When the HPL300, HPL470, or HPL500 press is full and the pump is off open the feed vent valve to relieve all pressure on the filter press and feed lines. Leave the valve open until the press is closed for the next run.
  • When finished with run on the Bench Press, disconnect the air supply from the bomb and allow it to vent to atmospheric pressure
  • When releasing the hydraulic pressure do not stand along side of the press, there should not be any pressure on the filter press, but if there is any slurry will tend to spew out the side.

9.2.3   Membrane

  • Observe all the rules for the recessed chamber press.
  • Additionally, always make sure that the maximum membrane pressure is 225 psig.
  • Also, after inflating the membrane (membrane squeeze will last 15 – 30 min) vent the membranes to atmosphere so there is no pressure on the membranes. Note the gas or water supply should have a shut off or isolation valve before the membrane header.
  • Before opening the press disconnect any hoses connected to the membrane plates, this will insure that the membranes are at atmospheric pressure
  • One operating note, leave the membranes disconnected until needed for inflation.

9.3       Chemical

9.3.1    General

  • Wash one’s hands after working any chemical before eating or when leaving for the day. Some chemicals may be on the hands and without causing skin burns or noticeable irritation but could be dangerous if ingested.
  • Wear safety glasses to prevent splashes from damaging one’s eyes. Contact lens should not be worn when working with chemicals
  • Do not wear loose fitting clothing.
  • Wear shoes if safety shoes or boots are not required by local plant rules
  • Do not wear shorts; one must wear pants, jeans, or trousers.
  • Wear a shirt – clothing is the first line of protection
  • Some the chemicals may attack the fibers in a fabric or permanently stain, so wear old cloths
  • Long hair must be tied back.
  • Review the MSDS for complete health and safety information, as well as required personal protective equipment.
  • Always respect the chemical and slurries one comes in contact with. Any chemical or slurry handled carelessly could be potentially very dangerous to individuals exposed to them.

9.3.2   Ferric Chloride Solutions

  • These are very acidic solutions that are very corrosive. Primary exposure concerns are skin, eyes, and ingestion.  Required safety equipment includes gloves and safety glasses.  Eye wash and safety shower must be available.

9.3.3   Hydrated Lime

  • This is a corrosive, powdery, alkaline white solid. Primary exposure concerns of the solid is dust exposure.  The dust will dry skin, damage mucous membranes, and damage lungs.  Lime slurries are corrosive to eyes and skin and damaging when ingested to the esophagus.  Required safety equipment includes gloves and safety glasses.  Eye wash and safety shower must be available.

9.3.4   Polymer

  • Polymer solutions and damp polymer solids are very slippery and must be washed down to prevent a slipping hazard. Good chemical hygiene must be practiced but most polymers and polymer solutions are not as aggressive as either ferric chloride or lime.

9.3.5   Nitrogen

  • Nitrogen is a compressed gas, in a high-pressure cylinder; a full cylinder has a pressure of about 2000 psig. The cylinder must be properly secured before being used.  If the tank is not properly secured and it falls over, the valve on the tank can break off.  This will cause a very rapid expansion of the nitrogen and the cylinder will become a very dangerous projectile.  In addition, nitrogen is an asphyxiation hazard because it can displace oxygen in air and this particularly dangerous in small, poorly ventilated rooms.  Use nitrogen in a well-ventilated room and take due precautions to prevent nitrogen leaks (make sure all fittings are tight).

9.3.6   Slurries

  • The potential hazards of the various slurries one might test are very broad. One must review the MSDS for the health and safety information even when one believes the slurry is nearly identical to one that was tested previously.
  • Municipal sewage can make one ill because of the bacteria in the sewage. One must thoroughly wash one’s hands before eating.

9.4       Mechanical and Electrical

9.4.1    Important Note

  • Review the OEM manuals for detailed safety information and required safety precautions

9.4.2   Pumps

  • On all the pumps make sure that all the pipe fittings and connections are tightened properly.
  • The large Abel pump belt guard must be in place. Make sure that it is properly connected and grounded to avoid electrical shock.  Be aware of all pinch points that could occur while the pump is operating.  When servicing the pump, make sure the power is off and that any process pressure has been relieved.  Do not service the pump if there is power from the MCC to the pump, the power must be turned off or disconnected at the MCC.
  • On the AOD pumps remove the air connection and relieve all the process pressure before working on the pump.

9.4.3   Mixers

  • Make sure mixers are properly installed and that the tank wall or mounting bracket is sturdy enough to support a mixer during operation.
  • Keep hands and clothing clear of mixer shaft and blades while mixer is in use.
  • Disconnect the mixer from electrical power or air source before installing, adjusting, or removing.

9.4.4   General

  • Keep hose and electrical cords out of the way to avoid tripping hazards
  • Properly ground all electrical equipment.
  • Locate equipment and supplies to have easy access to all, keeping supplies out of the work area.
  • Inspect all hoses for damage or evidence of chemical attack. Discard all damaged hoses and replace.  Damaged or weakened hoses can burst unexpectedly while under pressure.