Digital Water Flow Meter

Most popular digital water flowmeters: rotameter flowmeters, turbine water flowmeters, electromagnetic water flowmeters, and vortex flowmeters for water volume measurement, positive displacement flowmeters, differential pressure flowmeters, Coriolis water mass flowmeter and ultrasonic water flowmeter, the following is a description of the principle, features, application overview for different digital water flow meter types.

Turbine flowmeter for water measurement

Turbine flowmeter is a kind of velocity flowmeter. Turbine flow transmitter uses a multi-blade rotor (turbine) to sense the average water flow rate, then deriving the water flow rate or water total. Generally, it consists of a flow sensor and an integral display instrument to show water detecting information and turbine water meter parameter setting.
Turbine flowmeters, positive displacement flowmeters, and Coriolis mass flowmeters are known as the best repeatability and accuracy comparing with other types flow meters. Silver Automation Instruments can offer turbine meter as cheap inline water flow meter.
Advantages to use turbine flow meter for water metering:
(1) High precision can reach accuracy 0.5% to 0.25%:
(2) Good repeatability:
(3) Inline digital water flow meter has no zero drift, good anti-interference ability;
(4) Digital turbine flow transmitters to have LCD display to read water flow rate and cumulative water total flow;
(5) 4-20mA and pulse output, RS485 communications possibility;
(6) Battery operated water flow meter or 24V DC power supply
(7) Wide range for water measurement
(8) Compact structure and light weight for easy transportation
(9) Inline water flow meter with various size, from low flow rate water flow meter with only 1/8 inch dial size to 10”, DN250 water flow meter, normal buy water flow meter sizes are :1/2” water flow meter,  1 inch water flow meter, 2 inch digital water flow meter GPM, 3”, 4 inch and DN150 water turbine flow meters;
Disadvantages:
(1)Need regular calibration to ensure accuracy:
(2) The physical properties of the water have a great influence on the flow characteristics.
Application for turbine water flow meter:
Turbine flowmeters are widely used in the following measurement objects: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas and cryogenic fluid systems.  Only clean water can be measured by inline digital water flow meter turbine type, such as tap water, drinking water, RO Reverse Osmosis water, clean water, soft water, pure water, mineral water, distilled water, bottle water, dirty or slurry water should go for magnetic water flow meter.

Vortex flowmeter for water measurement

Vortex flowmeter is an instrument that places a bluff vortex generator in the water, and the fluid is alternately separated on both sides of the generator to release two series of regularly staggered vortices.
Vortex flowmeter can be divided into: stress type, strain type, capacitive type, thermal type, vibrating body type, photoelectric type and ultrasonic type according to the frequency detection method. Vortex flowmeter is the youngest type of flowmeter. However, it has developed rapidly and has now become a common type of flowmeter.
Advantages for water measurement by Vortex flow meter
(1) Simple and firm structure, without moving parts inside flow sensor
(2) Suitable for many types of fluids, such as normal clean water, high temperature water flow measurement, condensed water flow meter, fully demineralized water, boiler feedwater, digital hot water flow meters; the max water temperature by vortex flow meter is 300 °C.
(3) Accuracy: 1.0% for water flow measurement
(4) Wide range, turn down ratio for water is around 1:10;
(5) Inline digital water flow meter small pressure loss in the closed water pipeline;
(6) Industrial digital water flow meter with electronic indicator, current output and 4-20Ma, pulse output or HART protocol;
(7) Inline vortex flow meter for water flow range

15mm, 1/2”, water flow range 1.3-13 GPM
20mm, 3/4” inch dial size, water flow range: 4.4- 30 GPM
25mm, DN25, 1 inch digital water flow meter, range: 1.6-10 cubic meter per hour
32mm, 1-1/4” vortex flow range for water: 2.1-15 m3/h
40mm,1-1/2” vortex shedding flow meter range: 11-110 gpm;
50 DN, 2 inch digital water flow meter, 15-150gpm water metering range;
65,2-1/2 inch water meter: 6.5~68 m3/h
80, 3 inch water flow meter range 10-100 m3/h
100mm, DN100, 4inch digital water flow range: 66-660 GPM
125mm vortex water flow meter range: 15.8-158 cfm;
DN150, 6 inch large water flow meter: 40-350 m³/h
200,DN200, 8 inch water flow meter, flow range: 22-180L/s
DN250,10” digital water flow meter can detect water flow from 70 to 559 CFM water flow;
DN300 metering range : 180-1800 m3/h;

Disadvantages:

(1) It is not suitable for low Reynolds number measurement;

(2) Long straight pipe section is required before and after vortex shedding flow sensor;

(3) The meter coefficient is lower (compared with turbine flowmeter):
4) The vortex meter is not suitable for water pulsating flow and multiphase flow;

Electromagnetic flowmeter for water flow measurement

Electromagnetic flowmeter is a kind of instrument for measuring conductive water made according to Faraday's law of electromagnetic induction. Electromagnetic flowmeter has a series of excellent features, which can solve the problems that other flowmeters are not easy to apply, such as the measurement of dirty water flow and corrosive water flow;
In the 1970s and 1980s, there was a major breakthrough in electromagnetic flow technology, making it a widely used type of flowmeter, and the percentage of its use in flow meters continued to rise for it is cheap inline water flow meter.
Advantages of magnetic water flow meter

• (1) The measurement tube of magnetic water flow sensor is a smooth straight pipe, which will not be blocked by passing water, and is suitable for dirty water measurement, such as sewage, waste water, pulp water, mud water, industrial wastewater, raw water, ground water geothermal water at 120°C,effluent water, fire fighting water, ;
• (2) No pressure loss caused by water flow detection , the energy saving effect is good;
• (3) the measured volume flow is actually not significantly affected by changes in water density, viscosity, temperature, pressure and conductivity:
• (4) The flow range is large and can be made into large size water flow meter, such as 8inch water flow meter, 10” water meter, 12inch, DN500,DN600,DN900, 1000mm dial size water flow meters;
• (5)  Mag water flow meter not only measure dirty water flow, but also can be made into acid water flow meter or NaOH water flow meter, such as water solution with HCL, Nitric Acid, sulfuric acid.,etc
• (9) Digital magnetic water flow meter can be with integral or remote display, option with MOBUS ,HART and profibus-DP water flow meters;
• (10) Magnetic water flow meter has may flow units for water measurement, such as m3/h, GPM, gph, kg/h, TPH.,etc

Disadvantages:
(1) Magnetic water meter cannot measure water with very low conductivity, such as pure water, demineralized water, distilled water.,etc
(2) Magnetic water flow meter cannot measure water with vapors or steam; also water should not have large bubbles’
(3) The max water temperature for inline digital water flow meter, Silver automation instruments water flow meter is 160°C;
Application overview:
Electromagnetic flowmeters are widely used, and large-diameter size magnetic water meters are mostly used in water supply and drainage projects: medium and small size mag meters are often used in high-demand or difficult-to-measure occasions, such as the control of cooling water in blast furnace tuyere in the iron and steel industry, and the measurement of pulp and black liquor in the paper industry. Strong corrosive liquid in chemical industry, ore pulp in non-ferrous metallurgical industry; small-diameter and micro-diameter are often used in places with hygiene requirements such as pharmaceutical industry, food industry, and biochemistry.
It is a kind of induction meter measuring the volume flow of conductive media. In addition to measuring the volume flow of normal conductive liquid, it can be used to measure the volume flow of strong corrosive liquid, such as strong acid and alkali, as well as mud, pulp, etc. It is widely used in oil, chemical, metallurgy, light spinning, paper making, environmental protection, food and other industries and municipal management, water conservancy construction, river dredging and other areas of flow measurement.

Variable area flow meter for water flow measurement

Variable area flow meter, also known as Float flowmeter, rotameter, it is a widely used cheap water flow meter. In a vertical conical tube that expands from bottom to top, the gravity of the float with a circular cross section is borne by the hydrodynamic force, so the float can rise and fall freely in the cone tube with water flow range change.
Float flowmeter is the most widely used classic DP flowmeter, it is especially perfect for small and micro flow water flow measurement.Float flow meters can be glass tube , plastic tube or metal tube variable area flow meter.
The glassl tube rotameter has a simple structure and is easy to use,it is a kind of very cheap rotameter to show water flow rate, cheap inline water flow meter.
The disadvantage of rotameter is that the pressure resistance is low, and there is a greater risk of the glass tube being fragile; VA flow meter for pipeline with small and low water flow measurement, the pressure loss is also very small.
Silver Automation Instruments sell metal tube rotameter, it can be mechanical rotameter without any power supply or metal tube rotameters with transmitters to have 4-20mA output,digital rotameter also has the possibility with HART or MODBUS for different process control or remote monitoring.

Differential pressure flowmeter for water measurement

Differential pressure flowmeter is an instrument that calculates the flow rate according to the differential pressure generated by the flow detection element installed in the pipeline, the known fluid conditions and the geometric dimensions of the detection element and the pipeline.
Differential pressure flowmeter consists of a primary device (detection piece) and a secondary device (differential pressure transmitter and flow computer). Differential pressure flowmeters are usually classified in the form of detection pieces, such as orifice flowmeters, Venturi flowmeters , V-cone flow meters.,etc
DP flow meters for water measurement has long history, it has stable performance and reliable measurement result.
It can be used for high pressure water flow measurement or high temperature water flow measurement , inline digital water flow meter.
Advantages:
(1) The most widely used DP flow meter is orifice plate flowmeter , the DP flow sensor has a firm structure, stable and reliable performance, and long service life;
(2) DP flow meter has a wide range of applications, and so far there is no other type of flowmeter that can be compared with it; Transmitters and display instruments are produced by different manufacturers, which is convenient for easy replacement;
Disadvantages:
(1) The measurement accuracy is generally low
(2) The rangibility is narrowing, generally only 3:1-4:1:
(3) Orifice plate need long straight pipeline when mounting the primary elements;
(4) Relative large pressure loss
Application overview:
Differential pressure flowmeter has a wide range of applications. It is used in various fluids in the flow measurement of closed pipelines, such as clean water, high temperature water, industrial high pressure water.,etc

Ultrasonic flowmeter for water measurement

Ultrasonic flow meters are instruments that measure flow by detecting the action of water flow on ultrasonic beams (or ultrasonic pulses).
According to the principle of signal detection, ultrasonic flowmeter can be divided into Transit time flow meter and Doppler flow meter.
Like electromagnetic flowmeters, ultrasonic flowmeters are unobstructed flowmeters because there is no obstruction in the water flow pipeline. They are a type of flowmeter suitable for solving difficult problems in flow measurement, especially in large water flow meters used in large-diameter pipeline.
Advantages:
(1) Non-contact water measurement, non-contact flow meter by just applying clamp on transducers on the pipe wall;
(2) No flow obstruction one the pipe, so no pressure loss;
(3) Low cost digital water flow meter for large water pipelines
Disadvantages:
The transit time ultrasonic water flow meter only apply for clean water measurement , cannot be used for waste water or water with suspended particles and air bubbles; Doppler water flow meter for waste water but with low measurement accuracy;

Coriolis Mass water Flow Meter

Coriolis mass flowmeter (CMF) is a direct water mass flow meter made by using the principle of Coriolis force proportional to the mass flow when the fluid flows in the vibrating tube.
Coriolis water flow meter price is not cheap and normally not very economical solution for water measurement; it is very high accuracy water mass flow meter, the accuracy can be 0.1%.
Coriolis flow meter is stainless steel water flow meter, we have 6mm, DN10, 1/2 inch, 1 inch , 2inch Coriolis water flow meters;
Digital water mass flow meter can also show water density on the flow meter electronic display;
Can measure different kinds of water, drilling mud, slurry pulp, sludge.,etc., inline digital water mass flow meter.

Positive Displacement water Flowmeter

Positive displacement flowmeter, referred to as PD flowmeter, is the most accurate type of flowmeter. It uses mechanical measuring elements to continuously divide the fluid into a single known volume part. According to the measurement the total fluids volume is measured by the number of times the chamber repeatedly fills and discharges a portion of that volume of fluid. Household water meters are PD flow meters, but in industry water flow measurement, SILVER AUTOMATION INSTRUMENTS developed a kind of micro PD flow meter for low flow water measurement. The water low flow can detect as low as 1 cc/min flow still with 0.5% high accuracy.

• This kind of low flow PD flow meter can be used in Deep Water Sampling, chip cutting, water treatment system, odorizing system, coolant ,ammonia water,perfume measurement.,etc;
• Low water flow range can be detected by PD flow meter:
• 0.5-150 ml/min,1-400 cc/min,1-800 ml/min,0.5-100LPH,0.2-21 CFM, 0.3-30 LPM, 0.1-26 GPM water flow;
• Digital water flow meter with pulse NPN or PNP mode;
• No straight pipeline need in the upstream and downstream of PD water flow meters;