LPM-101
LP-Gas Flowmeter
Operation & Maintenance
TABLE OF CONTENTS
Introduction
Installation
Before Installing the Flowmeter
When Installing
Operation
Maintenance
General Maintenance
Erratic Registration
Consistent Over or Under Registration
Calibration
Measuring Chamber Maintenance
To Remove and Disassemble
To Clean the Measuring Chamber
To Reassemble the Chamber in the
Flowmeter
Gear Train Maintenance
To Replace Gear Train
Change Gear Chart
Troubleshooting
INTRODUCTION
The Model LPM-101 LP-Gas flowmeter is a compact meter consist-
ing of all necessary components required for accurate measurement
of liquid propane.
LPM-101 utilizes the proven oscillating piston design. This precise
method of metering has been proven to be both accurate and de-
pendable in thousands of installations. The rotational movement of
the oscillating piston chamber is transferred through a gear train as-
sembly, which in turn can operate various types of registration de-
vices.
INSTALLATION
1. Plan the installation for maximum rate of delivery, sizing the sup-
ply tank outlet, piping and valve for free gravity flow to the pump
suction. To accomplish this, locate the pump as close as possible to
the supply tank and use short inlet connections with few restrictions.
Keep the number of elbows to a minimum, and use large radius el-
bows, wherever possible. To further reduce the likelihood of causing
vapor in the pump suction line, a pump bypass valve should be in-
stalled in a return line to the supply tank.
2. Locate the flowmeter at any convenient place in the pump dis-
charge line. If the flowmeter is to be operated under extremes of en-
vironment (dirt, water, physical damage, etc.), an enclosure or other
protection should be provided. Allow vertical clearance for removal
of the register . Do not install any bypass around the flowmeter; the
valve in such a line might eventually leak, work open, or be left open
causing improper measurement.
When Installing
Secure the connecting piping to prevent strain on the flowmeter cas-
ing. Use pipe compound sparingly or suitable pipe tapes on male
threads only. Provide the installation with means for pressure relief
as outlined in the National Fire Protection Association Pamphlet 58
or local codes and practices.
NOTE: All isolated sections of the system MUST be equipped
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with a hydrostatic relief device to prevent damage. Failure to
1
perform this precaution could result in serious injury or death
1
from explosion/fire.
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OPERATION
1
Pressurize the system slowly by allowing vapor to flow through the
1
vent line. Then pass sufficient liquid through the system to clear the
1
lines of air and vapor.
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After starting the pump, slowly open outlet valve downstream of the
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flowmeter. Check the rate of flow after the system is filled; it should
2
not exceed maximum indicated rate of flow18 gpm (68 lpm).
2
Adjust the external pump bypass to deliver the maximum practical
2
rate of flow for the least amount of pump pressure (see pump manu-
facturer's instructions).
2
Maximum working pressure on the system must not exceed 350 psi
(24.13 bar). Avoid the use of small diameter hose and excessive
2
pressures to achieve the desired flow rates; these may result in leak-
3
age and undue wear on the pump.
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Although all flowmeters are carefully calibrated and tested after as-
sembly and no changes should be necessary; field calibration is rec-
ommended after installation is complete.
MAINTENANCE
General Maintenance
For sustained accuracy of flowmeters, little maintenance is required
other than to see that the proper conditions of operation are pre-
served. Once the flowmeter has been installed correctly, these con-
ditions consist merely in guarding against foreign matter, such as
vapor, sediment, or water entering the measuring chamber. How-
ever, should any malfunction develop, do not dismantle the
flowmeter until the cause of the trouble has first been determined.
(Refer to TROUBLESHOOTING.)
Sediment - The liquid passing through the measuring chamber
must be free of grit and other forms of sediment to prevent unneces-
sary friction and to eliminate scoring of the piston and chamber
walls. Evidence of trouble from this source will be found in un-
der-registration of the flowmeter.
Vapor - Being an instrument that measures by volume, a flowmeter
will record the passage of vapor as well as the liquid being mea-
sured. Over-registration will result.
Water - Incidental water will cause no damage to the flowmeter.
Trouble from this source may be expected when water is allowed to
remain in the flowmeter.
Erratic Registration
Erratic registration is usually caused by vaporization of the product
or by dirt or pipe scale in the measuring chamber (under-registra-
tion). Clean the flowmeter if necessary, as directed in
MAINTENANCE.
Consistent Over- or Under- Registration
When the flowmeter consistently registers either more or less than is
delivered and no other cause in system function can be determined,
calibration of the metering system is recommended.
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