The industry's most authoritative handbook on flow measurement provides a road map to the field of flow measurement. This best-seller discusses strategies for problem solving and puts the whole array of types of flowmeters at the reader's disposal. The text includes laminar flow elements, critical flowmeters, statistics for measurement, laboratory primary standards, and uncertainty in flow measurement. Emphasis is placed on the importance of accuracy in measurements and ways of ensuring accuracy and avoiding equipment damage through correct forecast of operating conditions, flowmeter selection, installation, calibration, and maintenance. Fundamental considerations such as mixed-phase flow, piping effects, and flow conditioning are examined at length. The problem of attaining a meaningful flow signal through linearization, compensation, and totalization is discussed. Join the thousands of engineers, technicians, managers, and salespeople that have found this reference text an invaluable resource.
TABLE OF CONTENTS Chapter 22 - Insertion (Sampling) Flow Measurement
Most flow measurements are made by meters that are installed in-line such that
all of the fluid passes through the meter body. Insertion (sampling) flow measurement
is a different technique because the meter is inserted into the pipe and the
flow rate is inferred from the measurement at a point in the flow stream.
There are both similarities and differences between in-line and insertion techniques.
On the one hand, fluid properties, pipe flow phenomena, and the basic
principles of flow sensing are the same. There are significant differences, however,
in operating principles, installation, and applications.
| What Is an Insertion Flowmeter? An insertion flowmeter consists of three basic components: a sensor, a probe assembly, and electronic circuitry. The sensor provides a signal proportional to the velocity or flow rate at a point in the flowstream from which total flow rate is inferred. The circuitry properly conditions the raw signal from the sensor and performs required computational functions. The probe assembly rigidly positions the sensor within the flow and provides a process seal. | An insertion meter is inserted into the line. An inline meter is installed in the line. |
Where Can an Insertion Meter Be Used?
An insertion meter can be used in most flow measurement applications. Insertion
meters are available that utilize most of the traditional flow sensing technologies
(i.e., turbine, vortex, magnetic, dP). The range of fluid conditions (i.e.,
pressure, temperature, fluid type) under which insertion meters operate is similar
to that of in-line meters. The performance of the sensing techniques is likewise
similar.
Why Are Insertion Meters Used?
The applications in which an insertion meter may be a better choice than an inline
meter can be divided into three categories:
- Applications in which an insertion meter is the only option. This is the
case of large line sizes for which in-line meters are unavailable. Another
example is an application where the process cannot be shut down for
meter installation. - Applications in which the insertion meter is a more economical option.
Installations in intermediate pipe sizes are suited to either in-line or insertion
meters, but the insertion meter may be more economical. - The unique operation of an insertion meter can sometimes provide a better
solution. For example, the velocity range of an insertion meter can be
changed by installing a different sensor.
