Installation and Maintenance Instructions
ASCO™ 2/2 and 3/2 pinch valves NC-NO,
Anodised aluminium or stainless steel body, series 273 and 373
DESCRIPTION
The pressure operated 2-way and 3-way pinch valves series
273 and series 373, depending on the version, are equipped
with a piston-type operator of dia. 20, 40 and 50 mm. The
valve bodies are available in anodised auminium or AISI 316
stainless steel.
If the user replaces an element, ASCO will no longer be able
to assure the final product's traceability and the user will be
required to do so.
SPECIAL CONDITIONS FOR SAFETY USE
The valve must be kept in its original packaging as long
as it is left unused:
Storage conditions:
• protected from exposure to weather;
• storage temperature: -40°C to +70°C;
• relative humidity: 95%
After storage at low temperature, the valves must gradually
be brought to room temperature prior to pressurization.
FUNCTION
NC - normally closed: The valve is closed when the NC pilot
valve is de-energised. This is a fail-safe closed valve: if power
to the pilot valve fails or is turned off, the main valve will seal
the tubing thus stopping flow.
NO - normally open: The valve is open when the NC pilot
valve is de-energized. This is a fail-safe open valve: if power
to the pilot valve fails or is turned off, the main valve will
release the sealed tube thus allowing flow.
3/2 - Three ways - single effect cylinder. Considering the valve
upright the upper body overture is considered as NC side;
on the opposite the lower body overture is the NO. Fail-safe
mode is respectively in accordance to NC or NO function
described above.
3/2 - Three ways - Dual effect cylinder. In this construction the
definition of NC-NO is defined by how the inlet pressure is ap-
plied to the cylinder. Considering the valve upright should we
inflate form the top threaded port NC function is on the upper
side and NO is on the lower side. Alternatively by inflating from
the bottom threaded port the functions are inverted. Fail-safe
mode is respectively in accordance to NC or NO function de-
scribed above only when the piloting valve is activated.
See corresponding product leaflets (on valves and pilot
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valves) for min./max. pilot pressure.
PUTTING INTO SERVICE (See page 18)
The valves are designed to be operated within the technical
characteristics specified on the nameplate. Modifications to
the products may only be made with the manufacturer's or
his representative's prior consent.
Valves requires a 3-way pilot valve for proper operation. Air
supply should be clean, dry air. Use of a water separator and
filter may be required to properly prepare inlet air. Before in-
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stallation depressurize the piping system and clean internally.
The equipment may be mounted in any position, however
for optimal performance and lifetime the valve should be
mounted with the operator vertical and upright.
• Flexible tubes are not supplied with the valve. For the
recommended tubes please refer to the compatibility table
(See pages 26 to 29)
VALVE INSTALLATION
Valves' bodies are provided with a flanged design that
allows easy panel mounting (See page 18).
Maximum allowable panel thickness is 5 mm or 3/16".
Valves shall be properly fixed using two (2) M4 screws &
nuts or equivalent UNC-UNF-UNEF screws & nuts.
During assembling, the flange shall be positioned on the
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internal side of the panel (fig. 1, page 18).
SAFETY GUARD INSTALLATION
(See page 20)
The valves are provided with a safety guard to increase
the safety of the operators.
The safety guard is provided as optional kit and shall be
assembled after panel installation.
Assembling procedure:
• Remove the headless screw from the body
• Secure the safety guard support (yellow) as showed in
fig.2. Use the screw from the kit.
• The correct installation is when the movable cover snap
into the body.
TUBING INSTALLATION
Before installation depressurize the pilot valve and tubing
line for an optimal safety.
Adapter kit is provided for 1/4" valve to will guide the tube
inside the body valve. Before to place the adapter he valve
shall be installed on the panel, then the element can easily
snap into the body as described in fig.3 (see page 20).
Valves without manual override
NC valves:
• Open the valve supplying power to the pilot valve.
• Open the safety guard.
• Insert the tubing into the proper slot of the valve using both
hands. Hands shall be kept away from pinching element
during the operation.
• Close the safety guard.
• Close the valve by shutting down power to the pilot.
NO valves:
• Open the safety guard.
• Insert the tubing into the proper slot of the valve using both
hands. Hands shall be kept away from pinching element
during the operation.
• Close the safety guard.
• Close the valve by supplying power to the pilot.
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EN
Anodised aluminium or stainless steel body, series 273 and 373
3/2 valve (single and dual effect cylinder):
- Open the safety guard on NO side
- insert the tubing into the proper slot of the valve using both
hands. Hands shall be kept away from pinching element
during the operation.
- Close the safety guard on NO side.
- actuate the valve supplying power to the pilot valve
-Open the safety guard on NC side
- Insert the tubing into the proper slot of the valve using both
hands. Hands shall be kept away from pinching element
during this operation.
- Close the safety guard on NC side.
- Close the valve by shutting down power to the pilot.
Valves with manual override (NC version only)
The manual override feature allows to replace the flexible
tubing without need to supply power to the pilot valve. Nev-
ertheless to get a safer installation it is recommended to
follow these steps:
• Operate the manual override until the pinching element is
lifted above the tubing slot.
• Open the safety guard.
• Insert the tubing into the proper slot of the valve using both
hands. Hands shall be kept away from pinching element dur-
ing the operation.
• Close the safety guard.
• Disengage the manual override by unscrewing the knob.
The knob is provided with a mechanical stop that prevents
it from being disassembled from the valve. Stop unscrewing
immediately when the end of the stroke is reached.
The manual override is a stay-in-place feature. In case air
supply is activated accidentally when the manual override
is fully or partially engaged, the valve will remain fully open
or partially open depending on the stroke applied on the
manual command.
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Prior to putting the valve into operation, check for correct
operation of the valve in order to prevent injuries to op-
erators and damages to property.
It is user's responsibility to provide the proper guidance
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to the tubing system. Improper installation may result in
incorrect operation of the product and injuries to operators
or damages to property.
SAFETY
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CRUSH HAZARD
Pinch valves are high force clamping devices. They are
designed to close and pinch flexible tubing by applying
force on them. Keep fingers away from pinching ele-
ments during operations. Valve may close unexpect-
edly. Safety guard must be in place and closed when
the valves is operating, injuries may occur otherwise.
TUBING LIFETIME, MAX. PINCHING CYCLES
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These products are designed for use with soft, flexible
tubing. Tubing will wear over time and require replace-
ment. The number of useful cycles on any given tube
Installation and Maintenance Instructions
ASCO™ 2/2 and 3/2 pinch valves NC-NO,
set must be evaluated prior to use in a system. Regular
service of the tube set will reduce risk of tube rupture,
potential product and/or system damage.
WATER IMMERSION
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These products are not designed to operate immersed
in water. Liquid ingress into the pneumatic cylinder may
degrade performance and reduce useful life of the
product.
CORROSIVE LIQUIDS
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Corrosive liquids may eventually cause seal failures
and reduce the useful life of the product. Any corrosive
liquid should be removed from the surface of the
product immediately.
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CONDENSATION
Minor surface condensation may not pose an issue to
the product. However, condensation should be limited
to the front of the panel and should not be allowed to
migrate to the pneumatic cylinder. Fluid ingress into the
cylinder may degrade performance and reduce useful
life of the product.
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