Ultrasonic flow meters are devices that help calculate the flow of water by measuring the velocity of the liquid by using ultrasound. Ultrasonic flow meters are extremely useful as they particularly help in measuring the flow of waste water. They are ideal for measuring waste water flow as when distilled water is used on this kind of device, aerations have to be added. These flow meters work because of the acoustic properties found in the water and things like temperature, density viscosity and suspended particulates impact the result.

There are three kinds of ultrasonic flow meters that can be used to measure the flow of water. The first kind is known as transmission flow meter, which is also known as contrapropagating transit-time. The transmission flow meters are again of two types- in-line also known as intrusive or wetted meters and clamp-on (non-intrusive) meters. The second type of meter is known as the reflection or Doppler flow meter as it uses Doppler Effect to measure the flow of water. The third kind is called the open-channel flow meter.

To measure the flow of waste water using ultrasonic flow meters the basic principle of the Doppler Effect has to be understood. The Doppler Effect comes into play when the metering technique measures the changing frequencies of water flow that occurs due to discontinuities in the water. It uses a technique which is similar to measuring sound waves. The operation thus uses the frequency shift that reflects the suspended gas bubbles or particles that interrupts the motion of water.

To measure the flow of water, ultrasonic sound is transmitted into a pipe. When the ultrasonic sound passes through the discontinuities in the water, a difference in frequency is observed which is measured. This different frequency is directly proportional to the rate of flow of liquid. However, to ensure that the ultrasonic flow meter works effectively, the liquid should contain at least 100 parts per million (PPM) of 100 micron. This essentially means that the large suspended particles or bubbles should be found in water that is to be measured.

Since ultrasonic flow meters come in various forms and thus it is very important that a few things are remembered before choosing a flow meter.

• The liquid that is to be measured should have 100 ppm of 100 microns?
• A handheld monitor is necessary for repeatedly measuring the output. A continuous process monitor can also be used.
• Know the minimum and maximum flow rate of the pipe.
• Note the minimum and maximum process temperature and process pressure.
• The size of the pipe that is being used. It is very important that an appropriate size is used.
• Decide whether you would be using a digital output or an analog device.
• Before the ultrasonic flow meter is used to measure it should be noted whether the pipe will always be full or not.

Magnetic BTU meters provide numerous benefits due to their versatility across a broad range of applications. Magnetic BTU meters are vital where accuracy is paramount and can be used successfully to measure hot or cold water energy in a variety of heating/cooling systems. Typically, these systems consist of three parts: an electromagnetic flow sensor, a pair of temperature sensors and a main unit. The main unit is a powerful console which combines high accuracy measurement, temperature measurement and BTU calculation.

Magnetic flow sensors operate on the proven principles of the Faraday Law, and measure flow volume of the medium within a closed pipeline. Usually powered by a microprocessor and integrated circuitry, electromagnetic flow sensors provide reliable performance, accuracy, and trouble free performance over many years. The digital signal processing enables a wide measuring range while easy to read LCD screens makes readings fast and accurate.

Today's electromagnetic BTU meters offer the highest degree of billing-grade performance (up to 0.5% accuracy for flow, 0.15°F (0.08°C) for differential temperature), and are the ideal choice for a broad range of applications including HVAC, heating/cooling energy production, energy transfer, building management, university facility management, district heating and cooling, geothermal or solar hot water system monitoring.

Because accuracy is critical, the temperature sensors of these systems are typically are factory paired and calibrated to achieve better than 0.1°F (0.5°C) accuracy for temperature difference measurement. BTU calculations are in accordance with EN1434 heat meter standard and formulas have been carefully implemented in the microprocessor to virtually eliminate errors.

Today's magnetic BTYU meters also offer various output options including 4-20mA, dry contact, RS485/ Modbus, BACnet, LonWorks, wireless and more, and can also be easily integrated with BMS building automation systems and PLC units.

Like many industries, the water and energy utility sector have been forced to adopt change to remain competitive, profitable, and more than ever, environmentally responsible. These business drivers have seen the development of new enabling technologies, giving birth to smarter, more efficient water management systems such as Advanced Metering Infrastructure (AMI) and Automatic Meter Reading (AMR). These state-of-the-art systems combine advanced technology, automation, wireless transfer, and analytics to enable a new level of accuracy and efficiency in water measurement and utility metering.

The days of manual metering and billing are slowly coming to a close. For over 15 years, public utility companies and their operator networks have responded to new trends in water efficiency and conservation by leveraging the power of remote reading, real-time data, and powerful data analytics to deliver more accurate, predictive services to both commercial and residential customers. At the heart of these efforts lies the advanced metering infrastructure (AMI) which relies on automated, two-way communications between the water and energy consumer, and the utility providers. AMI provides a host of business benefits:

• Resource conservation - because of AMI's use of real-time data and analytics, water suppliers can better recognize usage trends and waste, and are better able to gauge allocation and delivery of resources

• Customer satisfaction - AMI provides dramatic improvements to energy and water allocation and availability, resulting in more accurate, timely billing

• Operational efficiency - By enabling automation and 24x7 operations, AMI has reduced time and complexity and eliminated virtually tens of thousands of man hours involved in traditional energy management

• Lower costs - Less complexity, combined with less time and fewer resources, has resulted in lower operating costs for suppliers, and smaller bills for consumer end-users.

The future of AMI is looking brighter than ever. It continues to provide an integrated platform for remote, continuous, two-way communications between utilities, meters, and consumers, and will continue to improve as we realize further advances in the software, hardware, and transmission sciences that power it.

With energy waste and costs on the rise, building owners and facilities managers have adopted submetering practices to gain granular control over utility costs. Traditionally, commercial buildings were viewed by utilities as a single "customer", relying on building managers to track energy output and consumption of each individual tenant. This approach is not only labor-intensive and inefficient, but ultimately, unfair to individual tenants.

From a cost perspective, the practice of submetering allows property managers greater accuracy and flexibility, enabling landlords and property managers to meter the usage of each individual tenant - and bill them exactly for the services used. This approach ensures equitable billing, encourages conservation, yields happier, more satisfied clients, and generally lowers costs for everybody involved.

From a conservation standpoint, studies have shown that submetering is one of the most effective ways to reduce energy consumption in multifamily and multitenant buildings. When properly implemented and adopted, submetering can often produce a 20 to 40% decrease in energy consumption on an annual basis. To support these efforts - the energy metering industry has responded with a broad range of submetering products for water, gas, oil, and electric energy measurement, across a broad range of property configurations.

A typical submetering system consists of a single meter to measure usage for the specific utility (oil, gas, water, electricity) for each unit, combined with a wireless telemetry system to send real time data to a centralized computer system for remote reading. A third party billing company is normally used to read the meter data and interpret and format a bill that can be sent to individual tenants. These submetering techniques can be used on new construction or to retrofit older buildings with aging infrastructure.

Typical applications for submetering include residential apartment buildings, condominiums, universities, shopping malls, commercial buildings and other large public facilities. Submetering benefits are clear:

• More fair and equitable billing means greater tenant satisfaction

• More accurate, efficient billings means higher profits and lower operating costs for building owners

• Greater energy conservation, means overall energy costs for all

With global pressure for energy conservation continuing to rise, submetering will play an increasingly critical role. Not only will submetering enable utility companies to accurately monitor energy use and reduce waste, but allow residents and businesses greater visibility into resource consumption, helping reduce energy costs on a global scale.