Tecfluid PT Series - Manual (Page 2)

Working principle
The flowmeter consists of a float inside a conical
tube. The rising flow pushes the float to an
equilibrium point. The area obtained between the
float and the orifice is proportional to the flow rate.
This type of measuring principle is known as
variable area.
The equilibrium point depends on :
− The float weight : Pf
− The fluid thrust : E
− The free flow area : Al
The area proportional to the flow rate will be:
Al = Ac - Af
where:
Ac = Flow measuring tube area
Af = Float area
Each position of the float corresponds to a flow
rate indicated on the scale printed on measuring
tube.
Rea ding
line
(See below)
2
RECEPTION
The flowmeter is supplied ready for installation and service.
The instrument is supplied packed for their protection during transport and storage. Likewise they
have blocking elements that should be removed before installation.
Turning the instrument up side down, check that the float moves freely up and down through the
whole length of the tube.
INSTALLATION
Before carrying out the installation, verify that the seals are made of a material that is suitable for
the fluid to be measured.
The instrument must be installed taking into account the following:
The fluid inlet will be in the bottom of the flowmeter (the one nearest the scale’s minimum value).
The fluid outlet will be in the top of the flowmeter (the one nearest the scale’s maximum value).
It is very important that the position of the instrument is completely vertical, given that deviations
of about 5º can produce errors of about 10% of the reading.
FLOW RATE READING
The float determines the flow rate measurement on the scale.
For the different shapes of floats, the readings must be taken at the height shown in the following
drawing.
Reading line