Dwyer CPF - Manual (Page 5)

AVERAGE V.I.C., CENTISTROKES, FOR STANDARD
SERIES PVF AND CPF FLOWMETERS
100% GPM,
SIZE 6
0.54 - 0.80
1.20 - 2.60
3.80 -7.00
10.0 - 23.0 CTS
3
7
15
25
100% GPM,
1-1/2˝ SIZE
11.0 - 15.0
21.0 - 35.0
50.0
70.0 - 120 CTS
50
100
250
500
VISCOSITY CONSIDERATIONS:
Each Series PVF and CPF liquid flowmeters has a so-called
“Viscosity Immunity Ceiling” (V.I.C.). Usually, if the viscosity of
the metered liquid is less than the V.I.C. of the meter, the
accuracy will not be influenced by changes in viscosity. When
greater than the V.I.C., the meter will be influenced significantly,
and must be calibrated for that viscosity. Effects of viscosity on
a given flowmeter are not always predictable. Two apparently
similar liquids with comparable densities and viscosities may
impact meter calibrations quite differently. The table below
provides general guidelines for the typical maximum viscosity for
meter models without affecting accuracy.
MAINTENANCE:
Occasional cleaning of the sight tube and internal sensing
elements to assure float visibility and continued accuracy is the
only maintenance necessary for Series PVF and CPF
Flowmeters. Frequency will depend on the application — in
most cases, and annual cleaning is adequate. It is not necessary
to remove the Series PVF and CPF flowmeters from the pipeline
for cleaning or replacing parts. The body remains plumbed into
the pipe, allowing easy service and even installation of different
sensing elements to accommodate new flow rates or fluids.
Upon final installation of the Series PVF and CPF Flowmeters,
no routine maintenance is required. A periodic check of the
system calibration is recommended. Occasional cleaning of the
sight tub and internal sensing elements us assure float visibility
and continued accuracy is the only maintenance necessary for
the Series PVF and CPF Flowmeters. Frequency will depend on
the application - in most cases, an annual cleaning is adequate.
It is not necessary to remove the flowmeter from the pipeline for
cleaning. Please follow the instructions in the manual under
“Inspection and Cleaning.” The Series PVF and CPF
Flowmeters are not field serviceable and should be returned if
repair is needed (field repair should not be attempted and may
void warranty). Be sure to contact customer service to receive a
return goods authorization number before shipping.
DISASSEMBLY: The spare parts sheet included for each
flowmeter model type ordered includes cutaway drawings.
Please refer to the appropriate sheet during the disassembly
and assembly procedures.
CAUTION:
BE SURE PRESSURE IS FULLY VENTED AND FLUIDS
COMPLETELY DRAINED BEFORE DISASSEMBLING THE
FLOWMETER. WEAR SAFETY GLASSES AND PROTECTIVE
CLOTHING IF THERE IS ANY CHANCE OF EXPOSURE TO
HAZARDOUS CHEMICALS.
The sight tubes of all standard Series PVF and CPF flowmeters
may be removed by, depending on model type: (a) removing the
cotter pins and pulling the lock rings out horizontally; (b)
removing the bolts from the body/sight tube flange; or (c)
removing the internal snap ring with retaining ring pliers. Using
hands only, pull the sight tube straight up out of the body with a
slight twisting motion, lifting it clear of the body and snorkel or
guide rod. Remove the float assembly by lifting it up and away
from the snorkel/guide rod (On PVC and CPVC the
snorkel/guide rod transition assembly must be lifted out with the
float). The core tube assembly may then be lifted out — if stuck,
CAREFULLY pry up at the top of the slot with a brass rod, taking
care not to damage the body or core tube.
INSPECTION & CLEANING
Inspect parts for nicks, scratches, chips, wear, and contaminant
build-up. The edges of the core tube slot, ID of the core tube,
and OD of the piston (largest section at the float assembly
bottom) are precision machined. Damage to these areas can
destroy the meter's accuracy. Also inspect the O-ring, the
bottom section of the sight tube, and the inside of the upper body
section. Damage to these areas may result in leaking. Clean,
rinse, and dry all parts carefully, including the O-ring, preferably
with a mild detergent and water and a soft cloth or soft tube
brush. If solvents are used, make sure they are compatible with
all meter parts (plastic sight tubes may be attacked by chemical
vapors or solvents —consult the factory).
CAUTION:
DO NOT SCRAPE OR USE ABRASIVE MATERIALS FOR
CLEANING.
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