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Apollo Flow Measurement
Ltd
Charles Street
Walsall
WS2 9LZ
Tel 01922 645647
Tel 0800 3286674
Tel +44 1922 645647
sales@apolloflow.co.uk
DFM VARIABLE AREA FLOWMETER
The DFM is a
low cost all plastic flowmeter that gives a visual indication of the flowrate
using a tube and float arrangement.
Low cost
Clear indication of the
flowrate
Easy installation
Good chemical resistance
Short lead
times
Optional high and low alarm relays
Application
The DFM is a well proven variable area flowmeter for the
measurement of clear liquids and gases. It is simple in operation, easy to
install and requires no maintenance. It gives a clear visual display of flow
rate. It has the option of being fitted with relay outputs for high and low
flow alarm conditions.
Instrumentation
The signal can be used for a local display, remote
display or converted for transmission to a separate control system. Apollo have
a range of instruments to suit all your requirements.
Principle of Operation
When a fluid flows through the vertical tapered metering
tube the float will rise until a point of equilibrium is reached where the
downward weight of the float is balanced by the upward thrust of the fluid.
This point will represent a specific flow rate. If the flowrate increases the
float will rise to a new point where the new upward thrust of the fluid is
balanced by the weight of the float. For a given set of fluid conditions the
float will be stable at positions that can be marked on a graduated scale on
the tapered tube. These divisions can be calibrated in units of volumetric
flow. The graduated scale depends on three factors: the shape and weight of the
float, the size and taper of the measuring tube and the density and viscosity
of the fluid.
Optional Alarms
Up to three reed switch volt free contacts can be added
to the flow tube. A magnetic float is used to close the contacts on passing
them with increasing flow. The contact will remain latched until the flow
causes the float to drop below the contact and open the switch. The contacts
are rated at 240V 5A max.
Calibration
All Apollo flowmeters are individually calibrated with
water and are traceable to national standards.
We provide you with a test
certificate for each meter showing the number of pulses per litre, which is
used to set the instrumentation.
Installation
The flowmeter should be installed with the flow
vertically upwards through the flowmeter. For accurate results ensure that the
pipework is vertical to within 2/3 degrees. The standard socket connections are
for use with rigid PVC imperial pipe. There are optional BSPF inserts available
in stainless steel . When used with liquids valves may be placed upstream or
downstream of the flowmeter. When used with gases the valves should always be
downstream of the flowmeter.
DFM 165 Series
| Nominal size BSP | Socketbore dia. mm | Air range Nm3/hour 1 bar abs. 20oC | Water range litre/hour 20oC |
| 3/8" | 17.1 | 0.2-1.0 | 3-22 |
| 3/8" | 17.1 | 0.2-2.5 | 5-50 |
| 3/8" | 17.1 | 0.6-3.6 | 10-90 |
| 3/8" | 17.1 | 0.5-9.0 | 25-250 |
DFM 170 Series
| Nominal size BSP | Socketbore dia. mm | Air range Nm3/hour 1 bar abs. 20oC | Water range litre/hour 20oC |
| 1/2" | 21.4 | 0.4-2.8 | 5-50 |
| 1/2" | 21.4 | 0.8-6.2 | 15-150 |
| 1/2" | 21.4 | 0.9-9.5 | 25-250 |
| 1/2" | 21.4 | 0-15.0 | 50-500 |
DFM 185 Series
| Nominal size BSP | Socketbore dia. mm | Air range Nm3/hour 1 bar abs. 20oC | Water range litre/hour 20oC |
| 3/4" | 26.7 | 0.5-5.0 | 15-150 |
| 3/4" | 26.7 | 2.0-14.0 | 40-400 |
| 3/4" | 26.7 | 2.5-22 | 60-600 |
| 3/4" | 26.7 | 4.0-34 | 100-1000 |
DFM 350 Series
| Nominal size ins BSP | Socket bore dia. mm | Air Range Nm3/hour 1 bar abs 20oC |
|
| 1" | 33.6 | 0.7-7.5 | 15-150 |
| 1" | 33.6 | 1.0-10 | 30-300 |
| 1" | 33.6 | 2.5-20 | 60-600 |
| 1" | 33.6 | 4-34 | 100-1000 |
| 11/4" | 42.2 | 5-50 | 150-1500 |
| 11/4" | 42.2 | 8.5-76 | 250-2500 |
| 11/4" | 48.3 | 8-70 | 200-2000 |
| 11/4" | 48.3 | 10-90 | 300-3000 |
| 2" | 60.3 | 14-125 | 400-4000 |
| 2" | 60.3 | 22-190 | 600-6000 |
| 2" | 60.3 | 35-300 | 1000-10000 |
| 21/2" | 75.2 | 50-500 | 1500-15000 |
| 21/2" | 75.2 | 80-720 | 2500-25000 |
| 21/2" | 75.2 | 400-1500 | 10000-50000 |
Specifications
| Accuracy: | +/- 2% for DFM350 +/- 4% for DFM165, 175 & 185 |
| Max. temperature: | PVC - 60oC |
| Polyamide - 75oC | |
| Polysulphon -100oC | |
| Max. pressure: | 10 bar operating at 20oC |
| Scaling: | Litre/hour H2O standard and 0-100% |
| Special scaling is available. |
Parts Materials
| Description | Standard material | Optional material |
| Tube | PVC | Polyamide, polysulphon |
| Float | PVC | PVDF |
| Trap | PVDF | |
| Union nut | PVC | Stainless steel |
| Insert | PVC | Stainless steel |
| O ring | EPDM | |
| Indicator | PVC |
To see available data sheets and manuals click here: Download Area
Click below to switch to the following
flowmeters:
RN Turbine| Hygienic Turbine
|Electromagnetic | Hoverflo |
Lowflo/Peltflo | Variable Area |
Oval Gear PD | Positive
Displacement | Mass | Water
Meter | Ultrasonic | Vortex