TSA Process Equipments Pvt. Ltd. Offers Reverse Osmosis Unit. TSA Process Equipments Pvt. Ltd. Manufactures piping needs of the food, beverages and pharmaceutical industries. The Reverse Osmosis Unit is a membrane separation unit. The Reverse Osmosis Unit is the forced passage of water through a membrane against the natural osmotic pressure to accomplish separation of water and ions. The Osmosis is a process which can be defined as a passage of liquid from weak solution to a more concentrated solution across a semi permeable membrane. The semi permeable membrane allows the passage of liquid [solvent] but does not allow solids [solutes] to pass through.