Macnaught 050 User Manual

Page 1 of 14

INSTRUCTION MANUAL

To the Owner

OVAL GEAR FLOWMETER

MECHANICAL MODEL 050 (2”)

PLEASE READ THIS SAFTEY INFORMATION
CAREFULLY BEFORE USE.

Read and retain this instruction manual to assist you
in the operation and maintenance of this product.

If you have any problems with the meter, refer to the
maintenance and trouble shooting sections of this
manual.

This manual contains connection and operating
instructions for meters with Mechanical Displays

If you need further assistance, contact your local
representative or distributor for advice.

This Flow Meter has incorporated the oval rotor
principal into its design. This has proven to be a
reliable and highly accurate method of measuring
flow.

Exceptional repeatability and high accuracy over a
wide range of fluid viscosities and flow rates are
features of the oval rotor design. With a low pressure
drop and high pressure rating oval rotor flow meters
are suitable for both gravity and pump (in line)
applications.

050 Mech

07.11

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CAUTION

Important Information

Operating Principle

Installation Procedure

WARNING

Before use, confirm the fluid to be used is
compatible with the meter. Refer to Industry
fluid compatibility charts or consult your local
representative for advice.

To prevent damage from dirt or foreign matter it is
recommended that a Y or Basket type 60 mesh
strainer be installed as close as possible to the
inlet side of the meter. Contact your local
representative for advice.

When a strainer is installed it should be
regularly inspected and cleaned. Failure to
keep the strainer clean will dramatically effect
flow meter performance.

To prevent damage caused by air purge slowly
fill the meter with fluid. To reduce pressure build
up turn off the pump at the end of each day.

Maintenance can be carried out to the liquid crystal
displays and pulse units without removing or
isolating the meter from the line. When
maintenance to any other part of the meter is
required, the meter must be isolated and the line
pressure reduced.

The reed switch pulse unit can cause inaccurate
rate counts when used with high speed counters. It is
advised that a debounce circuit be used. Contact

CAUTION

CAUTION

When fluid passes through the meter the rotors
turn, as shown below. The magnets which are
located in the rotors will pass across the pulser
circuit board (containing either Reed switches or Hall
Effect sensors). A signal is generated which is then
sent by the Pulse Circuit Board (PCB) to the relevant
LC display or receiving instrument..

1) It is recommended that when setting up pipe work
for meter installations a bypass line be included in
the design. This provides the facility for a meter to
be removed for maintenance without interrupting
production. (see figure above)

2) Use thread sealant on all pipe threads.

3) For pump applications ensure pipe work has
the appropriate working pressure rating to match
the pressure output of the pump. See Meter
Specifications section for further details.

4) Install a wire mesh strainer, Y or basket type
60 mesh (250 micron), as close as possible to
the inlet side of the meter.

5) Ensure that the meter is installed so that the
flow of the liquid is in the direction of the
arrows embossed on the meter body.

6) The meter can be installed in any
orientation as long as the meter
shafts are in a horizontal plane.
(Refer to figures to the right for
correct installation) The register
assembly may be orientated to suit
the individual.
Note: Incorrect installation can
cause premature wear of meter
components.

7) Do not over tighten meter connections. Note:
Incorrect installation can cause premature wear
of meter components.

8) It is important that after initial installation you
fill the line slowly, high speed air purge could
cause damage to the rotors.

9) Test the system for leaks.

10) Check the strainer for swarf or foreign material,
after the first 200 litres check periodically,
particularly if the flow rate decreases.

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Maintenance Procedures

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,
for item numbers.

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 (Item 12) and
remove the cover plate (Item 11).

4) Remove the six meter cap screws (Item 5) and
remove the meter cap (Item 4).

5) Remove rotors (Item 3).

Reassembly - Flow Meter

1) Before reassembling check the condition of
the rotors (replace if necessary).

2) Check that the smooth side of the rotors (not
the plug side) is facing you when inserting
the rotors, the smooth side of the rotor is the
magnet side. There is no difference between rotor
one or rotor two.

3) Replace the rotors (Item 3) onto the shafts at 90
degrees to each other (refer Fig) 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.

4) Re-check the operation of the rotors

5) Inspect the gears (Item 6) in the meter cap (Item

4) for wear. (Replace if required, refer to parts on
page 4)

6) Replace the o’ring (Item 2) into groove In the

meter cap, if the o’ring has grown or is damaged
in any way replace it with a new part.

7) Replace the meter cap making sure that the gear
on the rotor is meshing correctly with the gear in
the meter cap (Item 4). Insert the cap head
screws (Item 5) and tighten in a diagonal
sequence 1, 4, 2, 5, 3, 6.

8) Replace the cover plate inspect the o-ring
(item 10), bevel gear (Item 7), for wear or
damage. (Replace if necessary).

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Product Specifications

Problem Cause Remedy

Fluid will not flow
through meter

a) Foreign matter blocking rotors
b) Line strainer blocked
c) Damaged rotors
d) Meter connections over tightened
e) Fluid is too viscous

a) Dismantle meter, clean rotors (strainer must be fitted in
line)
b) Clean strainer
c) Replace rotors (Strainer must be fitted in line)
d) Re-adjust connections
e) See specifications for maximum viscosity

Reduced flow
through meter

a) Strainer is partially blocked
b) Fluid is too viscous

a) Clean strainer
b) See specifications for maximum viscosity

Meter reading
inaccurate

a) Fluid flow rate is too high or too low
b) Fluid is too viscous
c) Excess wear caused by incorrect
installation

a) See specifications for minimum and maximum flow rates
b) Bleed air from system
c) Check meter body and rotors. Replace as required. Refer
to installation instructions

Fluid flows but no
reading on meter

a) Bevel gear is loose on shaft
b) Rotor drive gear is damaged
c) Transmission gears damaged
d) Register gears damaged

a) Tighten grub screws
b) Replace rotor
c) Replace gears
d) Replace register assembly

Fluid leaks into
register

a) Seal worn or damaged on the cover
plate

a) Replace seal (Check seal compatibility with fluid)

Troubleshooting Guide

Flowmeter Mech

Metric US

‘F’ and ‘M’ Meters

Flow Range

Below 5 cP 15 to 500 L/min 4 to 130 G/min

5 to 1000 cP 15 to 500 L/min 4 to 130 G/min

‘S’ Meters

Flow Range

Below 5 cP 30 to 300 L/min 8 to 80 G/min

5 to 1000 cP 15 to 350 L/min 4 to 93 G/min

Maximum Operating Temperature (Standard / High Temperature) 80°C / 120°C 176°F / 248°F

Maximum Operating Pressure

1

3400 kPa 500 psi

Accuracy of Reading ±0.5%

1. Conforms to Directive 97/23/EC—Cat 1

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Exploded Diagram

Parts Identification

Item No. Part Description

1

Meter Body

2

Meter Cap 0-Ring

3

Rotor Set

4

Adaptor Bolts

5

Flanged Process Connection

6

Adaptor O-Rings

7

Threaded Process Connection

8

Meter Cap

9

Gear Set

10

Meter Cap Screws

11

Cover Plate O-Ring

12

Cover Plate and Gear Set

13

Cover Plate Screws