Chapter 9. Diagnostics and Troubleshooting

9.3.2 Pipe Problems

Improper pipe conditions and/or flowcell installation can cause problems with fluid flow measurement. Check the items below if you suspect this class of problem. Contact the factory for unsolved pipe-related problems.

1.THE INSIDE OF THE PIPE OR FLOWCELL MUST BE RELATIVELY CLEAN. Excessive build up of scale, rust, or debris will interfere with flow measurement. Generally, a thin coating or a solid well-adhered buildup on the pipe wall will not cause problems. Loose scale and thick coatings (such as tar or oil) will interfere with ultrasound transmission and may result in incorrect or unreliable measurements.

2.THE FLOWCELL ORIENTATION MUST NOT ALLOW SEDIMENT OR GAS ENTRAPMENT AT THE TRANSDUCER LOCATIONS. Sediment or gas trapped in the transducer ports for wetted transducers, or at the transducer locations for clamp-on transducers, will interfere with flow measurement. Realignment of the flowcell or transducers often cures these problems. In some cases different transducers may be used that protrude into the flow stream.

3.THE PIPE OR FLOWCELL DIMENSIONS MUST BE ACCURATE. The accuracy of your flow measurements will be no better than the accuracy of your programmed pipe or flowcell dimensions. If GE did not supply your flow cell, the dimensions you program must be consistent with the required flow accuracy. Check your pipe for wall thickness, diameter, dents, eccentricity, weld deformity, and straightness.

4.THE PIPE SURFACES SHOULD BE SMOOTH (FOR CLAMP-ON). When using clamp-on transducers, both the inside and the outside of the pipe at the transducer locations must be smooth. If the pipe is extremely rough, the ultrasonic signal will be scattered by the rough surface, and will not be received by the flowmeter, preventing flow measurement.

5.THE PIPE MUST ALLOW ULTRASOUND TO PASS THROUGH (FOR CLAMP-ON). Some pipe materials or linings such as Fiberglass (or generic fiber reinforced pipe), Teflon, and polyethylene, absorb ultrasound and may cause problems in clamp-on applications. Pipes with extremely thick walls or high OD to ID ratios may also present difficulties.

Transport® Model PT878 Portable Liquid Flowmeter User’s Manual

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GE PT878 user manual Pipe Problems

PT878 specifications

The GE PT878 is a state-of-the-art portable ultrasonic flow meter designed for the precise measurement of liquid flow in various applications. As part of General Electric’s renowned instrumentation lineup, the PT878 combines innovative technology with user-friendly features, making it an invaluable tool for engineers, technicians, and plant operators.

One of the standout characteristics of the PT878 is its non-invasive measurement capability. The meter utilizes clamp-on transducer technology, allowing it to be installed on the exterior of the pipe, eliminating the need for invasive procedures which can disrupt the system or require pipe cutting. This non-contact approach not only simplifies installation but also enhances the device’s versatility, as it can be applied to a wide range of pipe sizes and materials.

The PT878 leverages advanced digital signal processing and sophisticated algorithms to provide accurate and reliable flow measurements. It operates using the time-of-flight method, whereby ultrasonic signals are sent and received through the fluid in the pipeline to determine the flow rate. This technology allows for remarkable precision, ensuring that operational efficiency can be maintained.

Moreover, the PT878 is equipped with features such as a bright, easy-to-read display, intuitive navigation, and robustness against harsh environmental conditions. Its compact and lightweight design enhances portability, making it suitable for field applications. The meter operates on battery power, providing a long-lasting solution for remote monitoring and temporary installations.

Another impressive aspect of the PT878 is its ability to measure not only water but also a variety of liquids, from hydrocarbons to chemicals. It supports multiple measurement modes, including volumetric flow and velocity, offering a level of flexibility that caters to diverse industrial needs.

In addition to flow measurement, the PT878 offers data logging capabilities, allowing users to store and analyze flow data over time. This function is vital for understanding trends, diagnosing issues, and optimizing system performance. Users can easily transfer data to computers for comprehensive analysis, enhancing operational insights.

With its combination of innovative technology, user-friendliness, and robust measurements, the GE PT878 ultrasonic flow meter stands out as a comprehensive solution for industries requiring reliable liquid flow measurement. Whether in a manufacturing plant, a water treatment facility, or any application requiring fluid monitoring, the PT878 delivers exceptional performance and accuracy.