Company Profile

YSI ProDSS Assemblies: Multi-Parameter Water Quality Field Assessment Rigs

Quick Answer: YSI ProDSS assemblies combine pH, dissolved oxygen, conductivity, temperature, and depth sensors into one portable field rig. Water quality teams use these rigs to check surface water, groundwater, and discharge compliance. Silver Instruments is a flow meter manufacturer and supplier for water quality field rigs. We supply flow meters that connect to the same skid or sample line when flow data must be logged beside water quality data.

What You Get in a Typical YSI ProDSS Field Rig

Most YSI ProDSS field assessment rigs include a handheld display, a cable bundle, and a multi-sensor bulkhead. The bulkhead carries optical dissolved oxygen, pH, ORP, conductivity, temperature, and depth sensors. A field team can swap sensors in a few minutes because the bulkhead uses locking connectors. We have seen that setup on customer sites many times. One contractor in Malaysia runs twelve rigs across river basins and replaces conductivity sensors every six months.

Why Field Teams Prefer a Single Assembly

A single ProDSS assembly removes the need for separate handheld meters. Technicians carry one case to a river, pond, or outfall. The cable options range from 1 meter to 100 meters. Longer cables help with deep groundwater wells. In practice, most surface water teams use 10 meter or 30 meter cables. The sensor bulkhead stores calibration data. Because of that, field crews swap bulkheads instead of recalibrating each sensor at the truck.

Flow Meter Inputs for Multi-Parameter Rig Skids

Many water quality rigs now include a flow meter on the sample line. The YSI ProDSS handles water quality. A flow meter handles flow rate and total volume. Here is the thing. Water quality data without flow data leaves a gap in load calculations. Both data streams feed the same logger or SCADA panel. Silver Instruments supplies electromagnetic flow meters and oval gear flow meters for these skids. A desalination pilot plant in Oman used a DN25 electromagnetic flow meter with 4-20 mA HART output on the feed line. That signal went into the same PLC that recorded conductivity and pH from the ProDSS bulkhead.

Water Quality Parameters That Change Flow Meter Choice

Conductivity matters because electromagnetic flow meters need a minimum conductivity to measure accurately. Most natural water has enough conductivity. Ultra-pure water may not. Most engineers skip this part when they select a flow meter. But conductivity is the first check. Temperature affects sensor life and liner material. A wastewater plant in Brazil tests discharge at 35 °C and 1200 µS/cm. That is well within the range of a standard PTFE liner electromagnetic flow meter. For low flow chemical dosing on a pH control loop, an oval gear flow meter works better because the pulse output gives high resolution at low flow. We often recommend a DN15 oval gear flow meter for coagulant or acid dosing skids that sit beside a water quality rig.

Typical Field Rig Examples by Region

A river monitoring contractor in Vietnam uses a ProDSS assembly on a small boat. They measure dissolved oxygen and conductivity at 15 points per day. The flow meter is a battery powered electromagnetic unit with a DN50 sensor. Data logs onto a SD card. A mine water treatment site in Western Australia has a permanent skid with a ProDSS bulkhead in a flow cell and a DN80 electromagnetic flow meter on the discharge line. A fish farm in Ecuador checks temperature and dissolved oxygen every morning. They use a hand held ProDSS and a small DN15 oval gear flow meter on the oxygen injection line.

Recommended Flow Meters for Water Assessment Rigs

For clean river water and raw water intake, use an electromagnetic flow meter. Sizes from DN15 to DN300 cover most field skids. For chemical dosing, use an oval gear flow meter