The portables line from Panametrics, a Baker Hughes business, offers both ultrasonic liquid and gas clamp-on flow meters: The TransPort PT878GC for gas; and the TransPort PT900 for liquid. These ultrasonic flow meters utilize ultrasound to measure the velocity of a given fluid or gas - also known as "flow" - and are used in a wide variety of fluid and gas applications, from wastewater and various fuels to natural gas and compressed air.
These meters attach to pipe fixtures to measure the flow within the pipe. Quick installation and meter readings enable our users to continue their process without having to shut down. The meter’s portability allows the device to move to numerous measurement locations, making it easy to spot-check the flow, verify the flow meter, or temporarily install the device.
Of the two available types of ultrasonic flow meters, we offer one for liquid measurement and one for gas measurement:
- The TransPort PT900 uses a rugged and intuitive smart device/tablet and includes a new compact clamp-on fixture along with wireless capabilities. Its easy-to-use design gives operators confidence that their liquid measurements are accurate.
- The TransPort PT878GC is a clamp-on flow meter designed for short-term flow surveys in natural gas pipelines, compressed air, inert gas, or any other compressed gas application. With the ability to measure gas flow rates and then log and export important data, this useful meter measures erosive, corrosive, toxic, high-purity, and sterile gasses.
The TransPort PT900 is a portable ultrasonic liquid clamp-on flow meter. It easily attaches to the piping fixture to measure flow within the pipe. Users have no need to cut into the pipe and cause delays and downtime. The PT900 can also be used to spot-check other meters or deploy for temporary installations. Apps for the TransPort PT900 can now be found for Android and iOS mobile devices. - Get the app for iOS
This flow meter can be installed in just minutes for a variety of industries without needing to shut down:
- Water and wastewater / Cooling and heating water
- Ultrapure water and liquids / Water/glycol solutions
- Crude oil / Refined hydrocarbons
- Diesel and fuel oils / Lubricating oils
- Chemicals
- Food and beverage
- Pharmaceutical
Historically, clamp-on flow meters were limited to liquids because existing methods could not work on metal pipes containing gases.
Panametrics developed a new technology that extends all the benefits of clamp-on flow metering to gas measurement. This remarkable ultrasonic technology works with gases at high or low pressure in pipes made of metal and most other materials.
The TransPort PT878 portable gas flow meter is a complete ultrasonic flow metering system for measuring most gases including:
- Natural gas
- Compressed air
- Fuel gases
- Erosive & corrosive gases
- Toxic gases
- High-purity gases
- Air separation gases
This flow meter can be installed in just minutes without needing to shut down, thus avoiding costly downtime.
Ultrasonic flow meters use transit time to determine the liquid or gas flow in a pipeline.
Measured transit time consists not only of the time the ultrasonic signal spends in a fluid, but also of a portion of “dead time,” being the time that the electrical signal is converted into an acoustical signal and the time the acoustic signal travels inside the transducer.
In the case of Custody Transfer, ultrasonic flow meters are used to calculate the flow, and thus volume, of product being transferred from one party to another.
Obviously then, accuracy is of great importance to all parties involved, from those who are procuring and delivering raw product, producing a refined material, those tasked with delivering the material, to the eventual end recipient.
While there are many types of flow meters in use today, the ultrasonic flow meter is by far and away the most popular flow meter, thanks in part to its high accuracy and low maintenance design.
When selecting an ultrasonic flow meter for your specific application, you'll need to ask yourself:
- What are the unique properties of the fluid I am detecting?
- What pressures or temperatures are present?
- Is this for Custody Transfer, Municipal Metering, or something else?
- What is the min/max acceptable range for measurement?
- How large are the pipes (line size) you'll be attaching your detector to?
- Do you require a portable solution or a static one?
Ultrasonic flow meters calculate and report volumetric flow rates, and typically use transit-time to do so. Transit time is calculated when the difference between sound waves transmitted in the direction of fluid flow travels at a different speed than those traveling in the opposite direction. This calculated difference is proportional to fluid velocity.
Unlike other mechanical flow meters, ultrasonic flowmeters do not have any moving parts. Ultrasonic meters offer additional benefits by being easier to install, with minimal maintenance, especially when compared to other flow meter types.
There are two types of ultrasonic flow meters, which are defined by their measurement method, Doppler and Transit Time.
Doppler
One of the drawbacks to the Doppler version is that they require the liquid being measured to have bubbles in it, in order for the doppler signals to reflect off of them, to achieve an accurate measurement. The problem, of course, is that 1) you will need to introduce bubbles into your target liquid, 2) different bubbles travel at different velocities, and 3) a signal reflected by a particle may very well hit another particle or bubble, thus altering your results.
Transit Time
Transit time works in somewhat the opposite way of the Doppler method and does not require the presence of bubbles in your liquid. In the transit time version, measured transit time consists not only of the time the ultrasonic signal spends in a fluid but also of a portion of “dead time,” being the time that the electrical signal is converted into an acoustical signal and the time the acoustic signal travels inside the transducer.
By sending a pulse and measuring its reflection, the dead time is measured in real-time rather than using a preset value.
