Transport And Storage; Transport; Storage; Functional Description - GEM 8257 Installation, Operating And Maintenance Instructions

7

Transport and storage

7.1

Transport

Transport the solenoid valve carefully.
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Avoid knocks and vibration.
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7.2

Storage

Store the solenoid valve free from dust
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and moisture in its original packaging.
Store the solenoid valve only with the
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connections blocked off .
Avoid UV rays and direct sunlight.
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When storing over a longer period of
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time do not exceed storage temperatures
from -10° C to +20° C. Raised storage
temperatures may lead to a reduced life
of sealing materials.
Solvents, chemicals, acids, fuels or
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similar fl uids must not be stored in the
same room as valves and their spare
parts.
8

Functional description

The GEMÜ 8257 2/2-way solenoid valve
with a positive lift diaphragm has a brass
or stainless steel valve body. All medium
wetted parts are made of NBR, FPM,
EPDM, brass or stainless steel.
8.1

Normally closed

Functional description (NC)
Normally closed
The compression spring *705 in the
armature *702 closes the pilot seat 2.
The diaphragm *102 is pushed down
onto the main valve seat 1. The medium
fl ows through the control aperture 3 in the
diaphragm into the control chamber above
the diaphragm and thus increases the
closing force.
Switch position open:
When voltage is applied, the armature *702
is attracted to the pole surface of the bush.
The pressure of the medium from the control
chamber reduces towards the valve outlet
through the open pilot seat 2. More medium
fl ows away through the pilot seat than can
fl ow in through the control aperture 3 in the
diaphragm *102. The diff erential pressure
produced lifts the diaphragm thus opening
the main valve seat 1.
All the parts marked * are included in the
wearing parts kit. When ordering spare
parts, please state the complete valve order
number.
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8257