FLOWTECH OFMM-025 User manual

Oval Gear Flow Meter
Flowtech
Measuring Instruments Pvt Ltd
Email: [email protected] /[email protected]
Website: flowtech-instruments.com
Mobile Number: 8469769988 / 9428876496 / 8160255957

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1. Introduction
OMFF/OFS Series aluminium oval gear flow meter has the ability to handle a wide range of fluid viscosities with
exceptional levels of repeatability and durability, applying in the petroleum, chemical, food industry, etc.
It is also applicable in Diesel, Kerosene and Petrol fluid usage industries
Flowtech provides Fuel Flow Meter from FMIPL-OFMM-025 to 50 Positive Displacement Fuel Meter. The Diesel
Flow Meter FMIPL-OFMM-025 to 50 has also incorporated the oval rotor principal into its design.
This has proven to be a highly reliable and highly accurate method of measuring flow, providing exceptional
repeatability and high accuracy. The low pressure drop through the meter makes the meter ideally suited for use
in gravity applications or with the Diesel Flow Meter & Digital Diesel Flow Meter range of electric fuel pumps.
2. Technical Specification
Model
OFMM-025
OFS-025
OFMM-040
OFS-040
OFMM-050
OFS-050
Size
25MM
40MM
50MM
Min Flow (LPM)
12 L/Min
25 L/Min
30 L/Min
Max Flow (LPM)
120 L/Min
250 L/Min
300 L/Min
Accuracy
+/- 0.5%
+/- 0.5%
+/- 0.5%
Repeatability
0.03%
0.03%
0.03%
Max Viscosity
1000 CPS
1000 CPS
1000 CPS
Best Working Pressure
0.3 Mpa
0.3 Mpa
0.3 Mpa
3. Operating Principle
The oval gear flow meter comprises oval-shaped, geared rotors which
rotate within a housing of specified geometry as shown in the diagram
below. One of the rotors is fitted with a gearing pinion which (through
a secondary gearing set) transfers the rotation of the rotor to the
Mechanical Register. Fluid differential pressure causes the intermeshing gears to rotate, trapping a 'pocket' of
fluid between the gear and the outer housing and subsequently emptying the fluid pocket into the downstream
flow.
The measurement part of oval gear flow meter is
posed by two elliptical gears mesh with each
other and its shell (measuring room).
The flow meter works by two elliptical gears to
mesh with each other, its working process are as
follows: P1 in the figure shows the pressure of

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liquid from inlet side, to show the outlet pressure, the bottom rotor has no rotating torque even it
effected the liquid pressure, but the above gears will move by the rotating pressure. ln the status of the
above gears driving gear, and the bottom gear is driven gear.
Both of these two gears have rotating torque by the liquid press u/'e, and they move with the direction
of the arrow to space. The gear space is opposite to, the bottom gear is driving gear, and above gear is
driven gear. The bottom gear pushes the liquid out from the half-moon space under the liquid press
pushes liquid volume four times of "measurement room". So, as long as the rotation of gears, the liquid
volume can be counted.
4. Installation Guide
1. Flow Meter should be cleaned before installing pipes. If the liquid containing solid particles in the
upstream of the pipe, you must install filters. Only when the flow meter connected to the pipeline, can
you remove the interface on the piston to prevent debris from entering the meter
2. No Specific requirements on the front and back of the flow meter pipeline, it can be installed horizontally
or vertically. During the installation, this oval gear flow meter axis of rotation should be parallel to the
ground. Please stick to the Picture 4
3. The direction of the flow meter installation should be the same as shown in the direction of the arrow
with the liquid flow to the meter shell: installation position should pay attention to the ease of reading.
4. The flow meter should be installed on the output end of the pump. If installed in the suction side, the
pressure loss of the flow meter filter will lead to the increase of the pump negative suction pressure, the
liquid at the outflow of the pump shaft also causes the flow meter error increases, the flange of the pump
suction side should be designed to prevent leakage, otherwise, it can also cause the error increases to the
flow meter.
5. A filter should be installed at the front of the flow meter to prevent greater than 0.2mm tiny particles
blocking the flow meter and the filter should be easy to clean
6. The flow meter is preferably mounted in front of the one-way valve only unidirectional flow of the liquid
within the pipe to prevent the reverse rotation of the counting gear
7. The flow meter recommendations shown in Picture 5. The bypass valve can be installed in the vertical or
the other direction of the pipeline from the top down, from bottom to top, right to left from left to right
8. When using the flow meter makes sure the internal filled with liquid. If the liquid to be measured mixed
with a gas otherwise the measured gas and liquid mixing volume it will cause the measurement in error
accuracy. If the liquid is mixed with gas and oil and gas separator must be installed.
9. When the flow rate traffic exceeds the specified maximum flow the speed of the oval gear increased and
wear increases and the pressure loss increased dramatically and so it should be avoided though still
measured at below the minimum flow the error increases the viscosity of a liquid slow meter 10Pa.s start
the flow of about 1% of the maximum flow rate
10. When the flow meter is out the factory were used on the 7th mechanical oil calibration under ambient
conditions the viscosity of the oil due to room temperature changes and about 13 Pa.s at room
temperature. Theoretical volumetric flow meter measuring viscosity of the liquid changes does not affect
the measurement accuracy because the measurement of the amount of leakage is generated in the gap,

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the gap exists between the inner wall and the oval gear influenced by the viscosity of the liquid varies but
actually in a small flow liquid viscosity greater impact
11. When the flow meter is used to measure high viscosity liquid, generally the heating liquid reduce the
viscosity and then flow within the duct stop using the flow meter because the liquid inside cooling
becomes viscous. If enabled the flow meter external steam liquid shall get heat until the liquid viscosity
has been reduced in order to use the meter otherwise the mucus will bite transmission parts and cause
damage
12. The measured liquid temperature should not be higher than the predetermined value, if its exceed and it
will cause jammed and cannot move, the liquid temperature change will cause additional error of the
viscosity affect in addition the temperature increase will cause the increase in volume of the crescent
shaped space so that the flow will become slow
13. Pressure loss proportional to the square of the liquid flow, the liquid viscosity increases the pressure loss
is also increased
5. Inspection and Elimination of the Fault
Phenomena
Reason
Measurement
Remarks
The failure of the oval
gear rotation
1. Installation is jammed when the
gear impurities fall into the flow
meter
Reinstall removed after
cleaning. Installation follows
the mark on the oval gear
An annotated mark
installed oval gear
2. The measured liquid impure, filter
clogging impurities
Clearing filter to remove
impurities
3. The measured pressure of the
liquid is too small
Increase the pressure
Oval gear rotates but
the word wheel fixed
The drive wheel might be stuck
Remove impurities, if cause
gear damage and replace the
gear
Gear turns, abnormal
noise
Exceeding the specified value due to
the over run of the flow rate
Adjust the flow rate to the
specified value
The Counter turning of
the word wheel
The flow direction of the liquid
might be in the opposite way to the
arrow of the meter shell
Disassemble the flow meter as
the arrow direction
The error is too large
1. The flow is too small and below
the specified value
2. Bypass leak
3. Useful lives for too long oval gear
wear serious
4. Liquid containing gas
5. The liquid viscosity has a large
difference with the testing liquid
viscosity
Change a smaller diameter
flow meter
Negotiate with
Manufacturer
Check the bypass to prevent a
leak
Adjust the oval gear according
to the change range of the
error data
An oil and gas separator
should be installed at the
front of the flowmeter to
prevent the leak of the joint of
the flange
Choose a proper liquid
viscosity

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6. Maintenance Procedure
6.1 Disassembly - Flow Meter
Ensure that the fluid supply to the meter is disconnected, and the line pressure is released before disassembly.
Refer to the exploded parts diagram and parts list.
1. Remove the four screws located on the face of the register. Then remove the face plate cover including
register assembly
2. Remove the four register mounting screws and remove the lower half of the register housing.
3. Remove the six cover plate screws and remove the cover plate
4. Remove the six-meter cap screws and remove the meter cap
5. Remove the rotors
6.2 Reassembly –Flow Meter
1. Before reassembling check the condition of the rotors (replace if
necessary). Note: there is one long and one short shaft. The short
shaft is to accommodate the rotor with the gearing pinion fitted
2. Replace the rotors onto the shafts at 90 degrees to each other and
check their operation by turning either of the rotors. If the rotors
are not in mesh correctly or do not move freely, remove one of
the rotors and replace correctly at 90 degrees to the other rotor
3. Re-check the operation of the rotors
4. Inspect the gears in the meter cap for wear. (Replace if required, refer to exploded diagram)
5. Replace the o’ring into groove in the meter cap, if the o’ring has grown or is damaged in any way replace
it with a new part
6. Replace the meter cap making sure that the gear on the rotor is meshing correctly with the gear in the
meter cap. Insert the cap head screws and tighten in a diagonal sequence 1, 4, 2, 5, 3, 6
7. Replace the cover plate inspects the O-ring, bevel gear, for wear or damage. (Replace if necessary)
7. Applications
Chemical Production Plants, Food Industry, Pharmaceutical Industry, Cosmetic Industry, Oil and Gas Industry,
Water and Wastewater Industry, Pulp and Paper Industry, Printing, Automotive Industry, Textile Plants,
Petroleum Industry, Paints, Shipbuilding, Mining Industry, Metal Industry, Glue Industry