LPM-102
LP-Gas Flowmeter
Operation & Maintenance
INTRODUCTION
The Model LPM-102 LP-gas flowmeter is a com pact me ter con sist -
ing of all nec es sary com po nents re quired for ac cu rate mea sure -
ment of liq uid pro pane.
Prod uct en ter ing the flowmeter passes through a strainer as sem -
bly, pro vided to trap par ti cles that could cause pre ma ture
innacuracies in reg is tra tion.
The LPM102 in cor po rates a sleeve-type va por elim i na tion valve
that per mits a “leak” flow of ap prox i mately .02 gpm (75.7 cc)
back to the sup ply tank. This valve op er ates in con junc tion with
Liqua-Tech’s in no va tive soft seat pres sure dif fer en tial valve. The
valve’s pis ton moves away from its seat when at least 15 psi
(1.034 bar) above prod uct va por pres sure is main tained at the
mea sur ing cham ber out let. This en sures that only liq uid is mea -
sured by the me ter.
LPM-102 uti lizes the proven os cil lat ing pis ton de sign. This pre cise
method of me ter ing has been proven to be both ac cu rate and de -
pend able in thou sands of in stal la tions. The ro ta tional move ment
of the os cil lat ing pis ton cham ber is trans ferred through a gear
train as sem bly, which in turn can op er ate var i ous types of reg is -
tra tion de vices.
INSTALLATION
1. Plan the in stal la tion for max i mum rate of de liv ery, siz ing the
sup ply tank out let, pip ing and valve for free grav ity flow to the
pump suc tion. To ac com plish this, lo cate the pump as close as
pos si ble to the sup ply tank and use short in let con nec tions with
few re stric tions. Keep the num ber of el bows to a min i mum, and
use large ra dius el bows, wher ever pos si ble. To fur ther re duce the
like li hood of caus ing va por in the pump suc tion line, a pump by -
pass valve should be in stalled in a re turn line to the sup ply tank.
2. Lo cate the flowmeter at any con ve nient place in the pump dis -
charge line. If the flowmeter is to be op er ated un der ex tremes of
en vi ron ment (dirt, wa ter, phys i cal dam age, etc.), an en clo sure or
other pro tec tion should be pro vided. Al low 6” (15.24 cm) ver ti cal
clear ance for re moval of the reg is ter and va por re lease mech a -
nism . The clear ance for re mov ing the dif fer en tial valve (front on
right-hand as sem bly) is 3½" (8.89 cm). Do not in stall any by pass
around the flowmeter; the valve in such a line might even tu ally
leak, work open, or be left open caus ing im proper mea sure ment.
When In stalling
Se cure the con nect ing pip ing to pre vent strain on the flowmeter
cas ing. Use pipe com pound spar ingly or suit able pipe tapes on
male threads only. Pro vide the in stal la tion with means for pres -
sure re lief as out lined in the Na tional Fire Pro tec tion As so ci a tion
Pam phlet 58 or lo cal codes and prac tices.
NOTE: All isloated sec tions of the sys tem MUST be equipped
with a hyrdostatic re lief de vice to pre vent dam age. Fail ure
per form this pre cau tion could re sult in se ri ous in jury or
death from ex plo sion/fire.
Vent Line
The vent line from the flowmeter’s va por vent to the va por space
of the sup ply tank should be 3/8" (10 mm) min i mum in side di am -
e ter tube or pipe. A shut-off valve must be in stalled in the va por
vent line to per mit emp ty ing of the me ter for clean ing or when ser -
vice is per formed on the flowmeter. The va por re lease vent line
must be re turned to the sup ply tank and should not be made a
com mon con nec tion with other va por re turn lines or pump by pass
lines. When prop erly in stalled, this line must per mit free flow in ei -
ther di rec tion. If valve in vent line is closed, flowmeter will not
func tion. These in struc tions must be fol lowed in or der to main tain
proper func tion of the dif fer en tial valve.
NOTE: A va por re turn line should not be used from sup ply
tank to tank be ing filled, in as much as such con nec tion would
cause con fu sion as to the amount de liv ered as a re sult of pos -
si ble pas sage of va por in ei ther di rec tion.
OPERATION
Pres sur ize the sys tem slowly by al low ing va por to flow through the
vent line. Then pass suf fi cient liq uid through the sys tem to clear
the lines of air and va por.
Af ter start ing the pump, slowly open out let valve down stream of
the flowmeter. Check the rate of flow af ter the sys tem is filled; it
should not ex ceed max i mum in di cated rate of flow18 gpm (68
lpm).
Ad just the ex ter nal pump by pass to de liver the max i mum prac ti cal
rate of flow for the least amount of pump pres sure (see pump
man u fac turer’s in struc tions).
Max i mum work ing pres sure on the sys tem must not ex ceed 350
psi (24.13 bar). Avoid the use of small di am e ter hose and ex ces -
TABLE OF CONTENTS
In tro duc tion
1
In stal la tion
1
Be fore In stalling the Flowmeter
1
When In stalling
1
Vent Line
1
Op er a tion
1
Main te nance
2
Gen eral Main te nance
2
Er ratic Reg is tra tion
2
Con sis tent Over or Un der Reg is tra tion
2
Cal i bra tion On Un com pen sated Flowmeters
2
Cal i bra tion On Com pen sated Flowmeters
2
Mea suring Cham ber Main te nance
2
To Re move and Dis as sem ble
2
To Clean the Mea suring Cham ber
3
To Re as sem ble the Cham ber in the
Flowmeter
3
Gear Train Main te nance
To Re place Gear Train
3
Va por Re lease Main te nance
3
To Dis as sem ble
3
Strainer Main te nance
3
To In spect the Strainer
3
Dif fer en tial Valve Main te nance
4
Trou ble Shoot ing
4
1
Rev. 3/02
