FLOW METERS. FLOW RATE MEASUREMENTS

THEORY / SUBJECT OF THE OFFER

In accordance with current regulations, each water and wastewater management facility is required to account for the volume of disposed wastewater. Flow rate metering and measuring systems are discussed as part of the relevant regulations, e.g. in the “Water resource law”, “Environmental law”, “Collective water supply and waste disposal” and the government order “on environmental fees” and the orders of the President of the Central Office of Measures. 

There are currently several dozen methods of flow measurement in use by water and wastewater management facilities. The subject of our offer is the delivery, assembly and start-up of the instruments (flow meter(s)) for liquid volume measurements. Depending on Client requirements, the measurement can be carried out in OPEN or CLOSED channels with ultrasonic or electromagnetic sensors.

1. Liquid flow rate measurement in OPEN CHANNELS

THEORY / ASSUMPTIONS

One of the most cost effective and proven methods of flow measurement is the open channel measurement based on water rise methods. A liquid flow rate is measured based on the actual liquid level measured by the ultrasonic sensor at the hydraulic structure (flume or weir) converted into the value of flow ratio by the measuring transducer. Due to high accuracy, easy installation and low costs, the method enjoys ever growing popularity.

METHOD OF OPERATION

Liquid level measurement at the hydraulic structure includes measurement of ultrasonic beam passage time between the sensor and the surface of measured liquid. The value is used to determine the actual liquid flow by the flow meter, allowing for the relation between the level and flow rate for over 20 flumes and weirs.

MEASURING SET DESIGN

DI-BOX liquid flow rate measuring set includes:

1. M1600/M2160 MICROPROCESSOR TRANSDUCER

2. ULTRASONIC LEVEL SENSOR

* 1 + 2 = FLOWBOX FLOW METER

3. HYDRAULIC STRUCTURE (depending on application):

a) Palmer-Bowlus flume (click here)

b) Venturi flume (click here)

c) Parshall flume (click here)

d) measuring weir (click here)

LEGAL BASIS

Currently, the list of instruments subject to metrological inspection in accordance with article 8 of the regulation of 11 May 2001 „Trade Metrology Act” (Dziennik Ustaw of 2004 No. 243, item 2441 as amended) is specified in the regulation of the Minister of Economy of 27 December 2007 establishing the types of measuring instruments subject to legal metrological inspection and the scope of metrological inspection (Dziennik Ustaw of 2008 No. 3, item 13). The regulation does not establish the duty of metrological inspection of liquid meters in open channels, and the certification body informs that the liquid meters in open channels are not subject to metrological inspection and no approval or verification process is anticipated.

2. Liquid flow rate measurement in CLOSED CHANNELS

INTENDED USE: Electromagnetic flow meters are intended for liquid flow rate measurements in closed channels. The flow meters measure flow rate of conductive liquids, with and without impurities, aggressive or inert as well as conductive mixtures and pulps. Electrical conductivity of the medium for standard version shall exceed 5 mS/cm. The flow meters do not reduce pressure and do not have any mechanical parts. Electromagnetic flow meters measure volumetric flow of liquids with solid impurities. See: measurement with electromagnetic flow meter

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