Topic
Flow
15 guides across the knowledge base.
Differential Pressure Flow Measurement
Orifice plates, venturis, and flow nozzles: the square-root relationship, why turndown is limited, where the square root is taken, impulse line rules, and when a DP element is still the right choice against a mag meter.
10 min readUpdated Sep 5, 2026
Open Channel Flow Measurement
Flumes and weirs with a level sensor: how the head-discharge relationship works, Parshall flume and weir equations, where to put the sensor, submergence, and the errors that make a permit-reporting flow meter wrong.
11 min readUpdated Sep 5, 2026
Ultrasonic Flowmeters
Transit-time and Doppler ultrasonic flow measurement: how each works, which liquids each suits, clamp-on versus wetted transducers, the pipe data the meter needs, the accuracy to expect, and the installation details that decide whether to trust the reading.
10 min readUpdated Sep 5, 2026
Flowmeter Installation
The installation rules that decide whether a flowmeter reads correctly: straight run by meter type, keeping the pipe full, orientation, velocity range, grounding for magnetic meters, isolation and access, and the commissioning checks that prove the meter.
10 min readUpdated Sep 5, 2026
Flow Troubleshooting
A method for a flow reading that is wrong, noisy, zero, or disputed: establish the truth with an independent check, separate installation from configuration from signal chain, then the specific checks for magnetic, ultrasonic, and DP meters.
10 min readUpdated Sep 5, 2026
Differential Pressure
The differential pressure transmitter as an instrument: what it measures, static and overrange ratings, the three-valve manifold and the order of operations that protects the cell, and the applications from filter head loss to membrane TMP, flow, and level.
9 min readUpdated Sep 5, 2026
Frequency Signals
Frequency as a process signal: the instruments that produce it, how frequency differs from pulse counting, the K-factor and the conversion to flow, frequency inputs and period measurement at low rates, converters to 4-20 mA, noise, and how to verify one.
7 min readUpdated Sep 5, 2026
Pulse Signals
Pulse outputs for totalizing: flowmeters, energy meters, rain gauges, and feeders, output types, scaling in volume per pulse, counter inputs, pulse width and rate, debouncing reeds, totalizer retention and rollover, and verifying against the register.
7 min readUpdated Sep 5, 2026
Headworks Control
The first stop for raw wastewater: influent flow measurement, mechanical screens and their differential level control, grit removal, influent pumping where the plant needs it, the odor and hazardous atmosphere considerations that shape the electrical design, and what SCADA needs from the headworks.
10 min readUpdated Sep 5, 2026
RAS and WAS Control
Return and waste activated sludge: what each flow does for the process, RAS control by influent flow ratio or by blanket level, WAS control to a target sludge age or a target mixed liquor concentration, the flow and solids measurements each needs, and the pump and valve arrangements that make the setpoints achievable.
10 min readUpdated Sep 5, 2026
Raw Water
Controlling the front of a surface water plant: intake and screens, low-lift pumping, the raw water flow that paces the whole plant, the online quality instruments that warn of a changing source, and the alarms and ramp limits that keep the train stable.
9 min readUpdated Sep 5, 2026
Flow Control in Water Pumping
Controlling the flow a pumping system delivers: speed against valves, flow-paced pumping to a treatment rate, the flow loop with its ramp limits and its meter placement, and the loop tuning that keeps a flow controller steady.
8 min readUpdated Sep 5, 2026
Station Flow Control
Controlling the flow a lift station sends downstream: why a station would limit or match its flow, the plant hydraulic limit, the force main capacity, equalization, and wet weather, and the alarms.
8 min readUpdated Sep 5, 2026
How to Troubleshoot a Flowmeter
Work a flowmeter that reads wrong, reads zero, or reads with the pipe still: confirm the pipe is full and the flow is real, check the installation against the meter requirements, and compare against an independent measurement before adjusting anything.
9 min readUpdated Sep 5, 2026
Magnetic Flowmeters
Faraday's law applied to a pipe: how a mag meter works, the conductivity and full-pipe requirements, and why grounding decides whether it reads.
8 min readUpdated Aug 1, 2026
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