Haskel 8 Serie Instructions De Fonctionnement Et D'entretien page 5

8" Drive Liquid Pumps • OM-LP-800F
2.3.4 SUCTION CHARACTERISTICS
2.3.4.1 Non-Pressurized Liquid Supply
All models except 8HSFD-225 will do a creditable job of pulling in a full charge on each stroke from a
source at atmospheric pressure on low viscosity, low volatility liquids. Suction piping should be equivalent
or larger than pump inlet ports. The -100 model should be installed at or below tank minimum liquid level.
The lower ratio models, with efficiency can lift 10-20 inches depending on characteristics of the liquid.
Model 8HSFD-225 should be pressurized to about 500 psi for maximum performance using a Haskel M
series pump for supercharge with safety relief to protect it in the event of reverse leakage.
2.3.4.2 Pressurized Liquid Supply
The -40 and -65 models are unbalanced. Therefore a pressurized inlet will cause erratic fluctuation of
output pressure, so atmospheric or low pressure (up to 100 psi) inlet is recommended. The other models,
being balanced opposed, will readily accept inlet pressures up to their full catalog output pressure ratings.
This will assist the drive in both directions of stroke thus adding directly to the ultimate output pressure.
2.3.4.3 Pulsation "Hammer"
The -40 and -65 models, being single acting suction design, abruptly block inlet flow at the start of each
"push" stroke. If the suction piping is of any length, the sudden stop of the heavy column of fluid inside it
can result in a hammering that can soon cause it to fail. Therefore pulsation reduction at the liquid inlet of
these single acting suction models is strongly recommended by: Using a short pipe (10"-20") to a tank at
atmospheric pressure; or flexhose if any longer distance; a commercial pulsation dampener; low pressure
accumulator; or Haskel plenum.
3. Installation
3.1 Mounting
All models will operate in any position required for system operation.
3.2 Environment
All units are protected with plating or materials of construction for installation in normal indoor or outdoor
applications. Special considerations may be advisable on some components if atmosphere is corrosive. If
ambient temperatures will drop below freezing, dryers to prevent condensation of moisture in either the
drive or liquid section are advisable.
3.3 Drive System
Incoming air (or gas) piping and components must be large enough to provide sufficient flow for the cycle
rate desired. Minimum size to provide the pumping rates shown in the current catalog is 3/4" I.D. Complex
lines over a considerable distance should be 1" or larger.
The standard drive inlet is a 3/4" female pipe port located in the center of the cycling valve body. As
standard, the pilot air (or gas) to the cycling system is provided through the bent tube assembly from the
1/4" NPT tap below the 3/4" NPT drive inlet port. For external remote pilot, the tube assembly is removed,
the 1/4" NPT tap is plugged, and the pilot from an alternate source connected to the 1/8" NPT port in the
valve end cap. On new pumps, specify modification 29125 if this feature is desired. External pilot
pressure should be equal to or exceed drive pressure. The drive (and pilot if external) inlet system should
always include a filter since essentially all compressors introduce a considerable amount of
contamination.
The drive requires approximately 25 psi to trigger the valve spool and pilot piston as lubricated at the
factory. It is not necessary or desirable to use an airline lubricator. The pumps may be modified to
operate with <25 psig of drive pressure. Specify 51875-1 after base part number (e.g. 8DSFD-100-
51875).
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