1. Introduction
1.1. General
Valmet Mircowave Consistency Transmitter (Valmet
MCA) functions based on the measurement of mi-
crowave propagation time.
Microwaves are electromagnetic radiation; the flying
time depends on the media's dielectric constant. Flying
time is calculated as follows:
c = speed of light in a vacuum
e
r
= media's dielectric constant
In water microwaves advance at a much slower speed
that in wood fiber. Therefore, consistency can be calcu-
lated based on the time it takes the microwaves to
move through the measured mass.
The advantages of this measurement procedure are
pulp type-independence, insensitivity to flow speed,
and single-point calibration.
There are two different models of Valmet MCA sensors:
- Valmet MCA-F Fork sensor (figure 2).
- Valmet MCA-FT Flow-through sensors (figure 3).
Valmet MCA also includes a user interface known
as Transmitter Central Unit (TCU) (figure 1).
Fig. 1. Transmitter Central Unit (TCU).
Fig. 2. Valmet MCA-F.
Fig. 3. MCA-FT.
Installation & Owner’s manual OUL00298 V2.3 EN
7
Valmet Mircowave Consistency Transmitter
To Next Page
Loading...
