Purified Water Refill Station Product

Overview

A purified water refill station sells drinking water by the liter into the customer's own container. Common at supermarkets, fuel stations, and street corners in regions where tap water quality or taste is poor, the machine treats municipal water on site through a multi-barrier train and dispenses it for a small fraction of bottled-water price, eliminating the bottle, the bottling plant, and the truck.

The treatment chain runs left to right through the cabinet: the Pretreatment Train train conditions the feed, the Reverse-Osmosis Module removes dissolved solids, the Storage Tank tank buffers production against demand, and the Post-Treatment Train gives a final taste, particulate, and microbial barrier on the way to the Dispensing Bay. The Payment System stack and Control Electronics meter every liter against paid credit.

Treatment train

Pretreatment exists mainly to protect the membrane. The Sediment Filter takes out particles above 5 µm that would foul the membrane surface, and two Carbon Filter stages strip chlorine, because free chlorine chemically attacks thin-film composite RO material and will destroy a membrane in weeks. A Pressure Sensor ahead of the membrane lets the controller detect clogged pre-filters as a pressure drop and flag a service visit before production falls off.

Reverse osmosis is the working heart. The Booster Pump raises feed pressure to 8-12 bar and pushes it across the RO Membrane Element elements in their Membrane Housing vessels. Water molecules pass the membrane; 96-99 % of dissolved salts, heavy metals, nitrates, and essentially all microorganisms do not. The Concentrate Valve sets the recovery ratio, typically 25-50 %: the rest of the feed leaves as concentrate to drain, carrying the rejected solids with it. Two TDS Probe conductivity probes, one on feed and one on permeate, let the controller compute rejection continuously, and a Flush Valve fast-flushes the membrane surface at intervals to wash off accumulating scale precursors.

Because RO is slow relative to dispensing, permeate collects in the Tank Body, a 200-500 L food-grade tank. Its Level Switch Set start and stop the RO module, its Vent Filter lets it breathe through a 0.2 µm hydrophobic barrier, and a Recirculation Pump periodically loops the stored water through the UV stage so it never stagnates. Stored RO water is aggressive and slightly acidic, so the Remineralizer in the polish train adds back calcium and magnesium carbonates, raising pH toward neutral and improving taste; the Post-Carbon Filter cartridge polishes flavor and the Final Filter is an absolute 0.2 µm membrane that stops anything picked up downstream of the RO stage.

The last barrier is the UV Sterilizer. Water flows through a polished UV Chamber around a Quartz Sleeve containing a low-pressure mercury UV-C Lamp emitting at 254 nm. A dose of 30-40 mJ/cm² inactivates bacteria, viruses, and protozoan cysts by damaging their DNA. The UV Ballast reports lamp current to the controller, which locks out dispensing if the lamp fails — a fail-safe required by NSF/ANSI 55 Class A practice.

Dispensing and payment

A customer places a container on the Bottle Shelf, pays at the Coin Acceptor, Card Reader, or Token Reader, and selects a volume on the LCD Panel. The Main Control Board opens the Dispense Valve, runs the Delivery Pump, and counts pulses from the Flow Meter until the paid volume — accurate to about ±1 % — has passed the Fill Nozzle. The nozzle is shrouded so hands and bottle necks cannot touch the wetted tip, and the Catch Basin drains spills. Regular customers commonly use RFID tokens or punch cards debited per liter, which is faster than coins for the typical 19 L carboy fill at 8-15 L/min.

Operations

The economics depend on consumable management, and the Telemetry Modem reports the numbers that matter: liters sold, permeate TDS (a rising value means membrane exhaustion), pre-filter differential pressure, and UV lamp hours. A service route operator changes sediment and carbon cartridges every 3-6 months, the UV lamp yearly, and membranes every 2-4 years depending on feed water. The cabinet's Freeze Heater protects the plumbing in outdoor winter installs, and periodic sanitization — draining the tank via the Tank Drain Valve and circulating sanitizer through the loop — keeps the downstream side compliant with drinking-water vending regulations.