Dresser iRMR Series User manual

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An EN ISO 9001: 2000 certified Company
iTN 30107rev00_ENGLISH
Installation and operation manual
Series: iMRM and iMRM-TWIN

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Installation and operation manual
Series: iMRM and iMRM-TWIN
Document Conventions
Warning
Indicates a procedure that has to be followed strictly as contravention
could result in escaping gas, and cause property damage, serious injury or death
Caution
Highlights a procedure which, if not strictly followed, can result in damage to the meter
Note
Is an important element of the procedure and should be observed
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Installation and operation manual
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CONTENTS
1 INTRODUCTION
2 GENERAL DESCRIPTION
3 RECEIVING, HANDLING AND STORAGE
4 INSTALLATION
5 MAINTENANCE
6 TROUBLE SHOOTING
7 TECHNICAL DATA
APPENDIX
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Installation and operation manual
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1 INTRODUCTION
The DRESSER iMRM Rotary Piston Gas Meter is a positive displacement type of meter which, by means of
two counter-rotating impellers and a counting mechanism, measures a known volume of gas with each
rotation. As a result of years of development and experience, DRESSER has been able to provide a meter
of unparalleled accuracy and turn down ratio. The construction of the meter and the materials used will
give years of faithful service even under very demanding conditions. The special designed coupling
guarantees flexibility in functionality for the future, since indexes and electronic switches can be replaced
on-site with the meter in-line.
The purpose of this manual is to provide a general guide to the installation, operation and care of a
standard DRESSER rotary gas meter. Every effort has been made to ensure that the information contained
in this manual is as accurate as possible; however, the continuous improvements which DRESSER makes to
its products may result in small inconsistencies. Custom manufactured meters or “specials” may also result
in small differences.
It is therefore prudent to consult the specific technical data sheets and other
documents which accompany the meter. If in any doubt, DRESSER should be
consulted.
2 GENERAL DESCRIPTION
The meter must be considered a part of the pressure containing system.
Operating Principle
The iMRM Rotary Meter is a positive displacement type of meter, passing pre-determined volumes of gas
by means of two counter-rotating impellers. Four times per each revolution a fixed unit of volume is
displaced through the measurement chambers. The flowing gas volume is proportional with the number of
revolutions of the output. The output of this model Rotary Gas Meter is a special designed magnetic
coupling where one part is fitted inside the meter body and the associated part is in the read-out unit. The
read-out unit can either be a mechanical index or an electronic index.
The typical design of the impeller tips allows considerable increased turn down ratios. Since the shape of
the impeller tip is at least two times larger compared to conventional impeller tips, the unregistered
leakage through the meter is significantly reduced resulting in an enlarged turn down ratio whereby the
meter is still less sensitive to installation stress or dirty gas.
The robust design of the iMRM is quite visible:
•the shape of the meter body
•the shape of the impellers
•the design of the main shafts and its bearings
•the material selected for the meter body
•the overall dimensions of the meter
•No bending, no twisting, no torque, no vibrations.
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Installation and operation manual
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The bearings are placed on the outside of the timing gears, which allows the connection between the
impellers and the timing gears to be much stronger then conventional type of rotor meters. Consequently,
these rotor meters are far less sensitive for improper start up.
The iMRM series rotary meters are designed to provide maximum comfort for the user. All functions, like
index, sight glass and oil filling plugs are accessible from the front side. This also makes it possible to
install the meter with the back against the wall, and as such saving space in, for instance basements
installations.
The mechanical index is 100% sealed avoiding condensation and accumulation of moisture. The index is
equipped with a slot for an electronic pulse box to allow maximum flexibility. By changing the pulse box,
the meter can be fitted on-site with several types of Low Frequency pick-ups (Reed switches or Wiegand
sensors).
The iMRM series of rotary meters are suitable for handling most types of clean, dry, common gases at
either constant or varying flow rates. The meter is not suitable for handling liquids. Measurement accuracy
and life expectancy can be impeded by excessive deposits of dirt of other types of foreign material present
in the gas stream.
Meters of standard construction are not directly suitable for handling oxygen, acetylene, biogas or sewage
gas. Specially constructed meters made of materials directly compatible with these and other gases are
available. Please contact the DRESSER for details.
The iMRM Series have a Maximum Allowable Operating Pressure (MAOP) rating. (Refer to the basic meter
body type-plate for the MAOP.)
Every meter is leak-tested at 1.1 times its MAOP and strength is tested at 1.5 times its MAOP. All in
accordance with International Standards and Codes. Important: The maximum working pressure of a
rotary meter is limited by casing design. Meters should not be installed where line pressure can exceed the
Maximum Allowable Operating Pressure.
The standard meter operating temperature range is -25°C to +55°C (EN12480 Class TC2).
Displaced volume measurement is completely independent of the gas specific gravity, temperature and
pressure. Displaced volume can be easily converted to volume at Standard conditions for elevated pressure
and varying temperature by application of the Basic or Ideal Gas Laws.
Meter Indexes
In some countries it is not allowed to change the index without supervision by the
local metrological authorities. Removing the seal could invalidate the metrological
status of the meter.
Using a special coupling, the index of the meter can be changed on-site with the meter in-line. This
enables to change the functionality in the future by just “one click”. The Index is already prepared for the
most commonly used functions. For information regarding availability contact DRESSER or the DRESSER
representative.
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Installation and operation manual
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Electronic pulse box
In some countries it is not allowed to change the pulse box without supervision by
the local metrological authorities. Removing the seal could invalidate the
metrological status of the meter.
Using a removable/external pulse box, the electronic output of the meter can be changed on-site with the
meter in-line. This enables to change the functionality of the electronic output in the future. The pulse box
is already prepared for the most commonly used functions. For information regarding availability contact
DRESSER or the DRESSER representative.
As there are many options for the electronic pulse box, details about the
functionality and the connectors are indicated on a separate document supplied
with the meter.
Accessories
Various accessories such as volume correctors, pressure and temperature transmitters, etc. can be fitted to
the IMRM. When connecting these accessories, reference should be made to the instructions and other
documents accompanying these products.
The IMRM can be equipped with two thermo wells for mounting a temperature sensor or a temperature
transmitter (max. 6 mm). The position of the two thermo wells allows calibration of volume correctors in
the field.
3 RECEIVING, HANDLING AND STORAGE
iMRM Rotary Meters are precision measurement instruments. Although of very rugged construction,
reasonable care should be taken during handling and storage.
At time of delivery:
1. check the packing list to account for all items received.
2. inspect each item for damage.
3. record any visible damage or shortages on the delivery record.
•file a claim with the carrier
•notify DRESSER or representative immediately
•Do not accept any shipment with evidence of mishandling in transit without making an
immediate inspection for damage and checking each meter for free rotation of the
impellers. All new meters should be checked for free rotation after arrival since damage to
internal working parts can exist without obvious external evidence.
•Should any serious problems be encountered during installation or initial operation of the
meter, notify DRESSER or representative immediately.
•Do not attempt repairs or adjustments, as doing so is a basis for voiding all claims for
warranty.
•If the meter is not tested or installed soon after receipt, store in a dry location. Leave the
protective caps or tape installed at the meter flanges. The caps or tape will provide
reasonable protection against atmospheric moisture.
•Do not add oil to the meter until after the meter has been installed in a permanent
installation and is ready for service.
•When reporting a suspected problem, please provide the following information:
-Your sales order number and/or DRESSER’s order number.
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Installation and operation manual
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-Meter model, serial number.
-Description of the problem
-Application information such as gas type, pressure, temperature and flow
characteristics.
Authorization for return is required for all DRESSER Products shipped to the Factory for repair, calibration,
warranty, exchange or credit. To obtain authorization for return of DRESSER products purchased from an
DRESSER Distributor of Representative, please contact the Distributor or Representative from whom the
product was purchased.
4 METER INSTALLATION
Installation only by authorized skilled people.
International, national, local and company safety rules are to be strictly followed
as contravention may result in serious injury or death.
Piping Configurations
The gas should be clean and free of liquids, dust or foreign material, which could
damage or block the meter impellers.
The iMRM series of rotary meters may be installed in either a Top Inlet (vertical) or a Side Inlet (horizontal)
configuration. The preferred or recommended installation is top inlet in a vertical pipe line with gas flow
downward. Although the design of the impellers tends to make the meter inherently self-cleaning, the top
inlet mounting allows gravity to pass dirt, pipe scale, or other debris trough the meter.
An additional recommendation is to install the meter in a side loop with a bypass adjacent to the main line.
Piping should be solid and properly aligned. Eliminate piping strains on the meter body.
Do not install the meter lower than the discharge pipe run to avoid accumulation of condensate and foreign
materials in the metering chamber. Use a Gasket Strainer or other Y-type strainer upstream of the meter to
remove liquids and foreign matter (pipe sealant, tape, weld slag, etc.) from the gas stream. A 100 micron
mesh screen is recommended.
Do not install a lubricated gas valve directly before a meter, as excess valve lubricant or other foreign
material can stop impeller rotation.
If over-speed conditions occur, a restricting flow orifice plate should be installed 2 to 4 pipe diameters
downstream of the meter outlet. Contact DRESSER for sizing, pricing and availability. Warranty does not
cover over-speed conditions.
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Installation and operation manual
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Placing meter in line
Remove the plastic protective caps or tape from both meter flanges prior to
meter installation.
1. Before installing a meter:
Make sure the upstream piping is clean by partially opening the valve to let a
sufficient amount of gas blow to atmosphere.
Insure the impellers turn freely and no objects or contaminants are in the measuring chamber.
Depending upon meter condition(for instance used meters), it may be necessary to flush the meter with
an approved solvent. After flushing, drain all solvent from the front cover. Make sure the measuring
chamber is clean and dry and the impellers turn freely.
2. Meter Orientation:
Connect meter inlet to the gas supply side of the line, insuring the gas flow will be in the same direction
as the arrow on the meter body nameplate (i.e., arrow pointing downward for top Inlet). See also fig.1 in
the appendix. Turn the index in the required position.
3. Install the meter without piping strain to prevent a binding of the impellers. Use pipe supports, as
required. Level the iM-RM series rotary gas meters to within 5mm/m, side-to-side and front-to-back.
4. Tighten flange bolts evenly in a cross-pattern. The flange bolts which should intrude at least 16 mm into
the meter should have a maximum torque of:
M12 (1/2 UNC): 55 Nm M16 (5/8 UNC): 130 Nm M20 (3/4 UNC): 180 Nm
5. Connect connectors to the index according to the diaphragms accompanying the meter.
If the meter is installed in a zone classified as hazardous area, then ensure all
connections are to intrinsic safe circuits.
6. There is only one oil reservoir in the iMRM SINGLE Series. Oil is shipped with each new meter in a
quantity sufficient to fill the reservoir in either a Top Inlet or a Side Inlet configuration. The iMRM TWIN
Series have oil reservoirs at the front and rear side of the meter.
Be sure that the meter is depressurized before removing the oil filling plugs.
7. Remove the filling plug in the front end cover. Slowly add oil to the end cover reservoir until the oil level
is to the centre of the oil gauge (sight glass). See also figures in the appendix. For the iMRM TWIN
Series, the same procedure is applicable for the rear side of the meter.
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Installation and operation manual
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Meter Start-UP
Slowly pressurize the meter in accordance with the following recommendations.
Do not exceed 5 psig/second (35 kPa/second) maximum when pressurizing. Rapid
pressurization can cause an over-speed condition which may damage the meter.
Resulting damage is not covered by warranty.
a) Open the bypass and outlet (downstream of meter) gas valves.
b) Partially open the meter inlet gas valve until the meter starts operating at low speed. Throttling
of the bypass valve may be necessary to initiate gas flow trough the meter. Verify gas is flowing
trough the meter by watching for movement of index drum. If movement is present, go to step c).
If the index drum is not turning, verify gas is being delivered to the meter. If gas is flowing to the
meter inlet and meter is not moving, go to step e).
c) Let the meter operate at low speed for several minutes. Listen closely for unusual scraping or
knocking sounds.
d) If operation is satisfactory, go directly to step f).
e) If unusual sounds are present or the meter is not turning, stop the installation procedure. Slowly
depressurize and vent all pressure from the meter set before checking for piping misalignment,
piping strain, torsion, or other related problems. Once the problem has been resolved, repeat the
start-up procedure beginning with step a).
f) Gradually open the inlet valve until full line flow is passing trough the meter and the inlet valve is
fully open.
g) Slowly close the bypass valve.
h) Follow your company authorized procedure or common practice to leak test the meter and all
connections. Soapy water and gas analysers are commonly used for this procedure.
An indication of the meter condition can be obtained by analysing the pressure drop
over the meter. It is recommended that the pressure drop over the new meter be
measured and recorded in the meter records. Future measurements can then be
compared to this value.
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Installation and operation manual
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5 MAINTENANCE
It is not allowed to carry out any repair or maintenance when the meter is
pressurized or in operation.
A rotary gas meter can be used for measurements of gases with extremely high and
low temperatures. Avoid direct contacts with the meter in operation since touching
the meter can cause serious injuries.
Periodic Inspections
It is not allowed to carry out any inspections when the meter and the adjacent
piping is pressurized.
Like all precision instruments an DRESSER rotary meter is vulnerable to abuse and
operating conditions beyond its specifications and limits.
It is prudent therefore to periodically check the security and running conditions of
the meter. Especially, when a significant over pressure or shock load has occurred,
or the installation is subjected to abnormal vibrations or if the gas is excessively
contaminated.
Removing metrological seals may invalidate the calibration.
Meters installed and maintained in accordance with the DRESSER recommendations can be expected to
operate dependably for many years. Proper oil level and cleanliness have the greatest effect on meter life
expectancy. The oil reservoir should be visually inspected for proper mid-gauge oil levels twice a year. Add
oil as necessary.
Use only Shell Morlina10 Oil or equivalent instrument grade oils approved for service by DRESSER.
Oil change frequency will depend upon the cleanliness of the gas being measured. Change oil when the
level increases significantly, indicating an accumulation of moisture. The iM-RM series of rotary meters
require an oil change once every 5 to 10 years under favourable operating conditions.
An EN ISO 9001: 2000 certified Company
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