![background image](http://html.mh-extra.com/html/red-seal-measurement/neptune/neptune_operating-and-maintenance_1428501016.webp)
Page 14
To Remove Back Pressure Valve
1. Remove Air Release and Strainer from the line by unbolting at inlet
flange and flowmeter inlet.
2. Remove strainer sleeves and air release valve.
3. Remove drain plug.
4. Hold block of wood (1
3
⁄
4
″
diam.) against back pressure valve and
knock valve out of housing by means of
1
⁄
2
″
diameter rod inserted
through drain plug hole.
GENERAL MAINTENANCE
In the maintenance of the accuracy of Actaris Neptune Flowmeters,
little is necessary other than to see that the proper conditions of operation are preserved. These
conditions, once the flowmeter has been properly installed, consist merely in guarding against for-
eign matter, such as air, sediment and water, entering the measuring chamber.
The liquid passing through the measuring chamber must be free of grit and other forms of
sediment in order to prevent unnecessary friction and the scoring of the piston and chamber walls.
Evidence of trouble from this source is under-registration of the flowmeter.
Periodic cleaning of the strainer at the inlet of the flowmeter will help to insure against this
trouble. In the design of this unit, particular care has been taken to make this operation as simple as
possible.
See page 13
.
Being an instrument which measures by volume, a flowmeter will record the passage of air as
well as the liquid being measured. Over-registration is the result. The air release valve is intended to
prevent this condition by venting this air before it passes through the measuring chamber.
Incidental water will cause no damage to the flowmeter. Trouble from this source may be ex-
pected only when water is allowed to stand in the flowmeter for considerable periods of time.
When washing trucks, care should be taken to cover the register. Water in the register will cause
trouble particularly in cold weather when ice may form and cause sticking.
Test with 50-gallon or larger test measures. Do not base calibration upon truck compartments or
on 5-gallon measures. Instructions for calibration will be found on page 5.
Preset Flowmeters should first be tested and adjusted without the Preset (set the register for
more than the test quantity); then test with the Preset. If the Preset mechanism does not trip cor-
rectly see instructions on “To Adjust the Tripping Point,” page 3.
Before a flowmeter is put in storage the measuring chamber must be flushed with a light lubri-
cating oil to prevent condensation damage.
To Remove Back
Pressure Valve
GENERAL
MAINTENANCE
Sediment
Air
Water
Testing
Storage
FIGURE 16
BACK PRESSURE
VALVE