Nordson-EFD-Series-450-Instructions - 第4页
Series 450 Autovalve / Snuff Back | Instructions / Parts Lists 4 www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide. Maintenance Two-compone…
Series 450 Autovalve / Snuff Back | Instructions / Parts Lists
3www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide.
Operation
The ON-OFF operation of the valve is controlled by movement of the piston inside the air cylinder (1).
In the OFF position, the piston retracts and the dual spool valves (75) seat into the front lip seals (3) which are located inside
the seat plate (8).
In the ON position, the piston and the spool valves move forward (75) which allows A & B fluids to pass through the manifold.
To eliminate drooling or stringing of the adhesive out of the mix tube, the spool valves (75) can be retracted through the front
lip seals (3). This snuff-back action is controlled by the adjustment screw (70) on the back of the air cylinder (1).
The snuff-back should be adjusted so the fluid just stops at the end of the mixing tube. Excessive snuff-back will cause
premature plugging of the valve.
A disposable Series 160 mixer can be attached to the manifold. If the operating pressure exceeds 10bar (150psi), we
recommend a metal jacket be used over the plastic mix tube. Refer to Catalog for details.
NOTE: For all reference numbers in parenthesis, see pages 7–11.
Your 450 AUTOVALVE in general...
• Designed to dispense two-component adhesives and sealants..
• Dispenses low or high viscosity urethanes, epoxies and silicones.
• Can be mounted for beads or timed shots; optional handle is available for hand held applications.
• Provides an ON-OFF function. The metering of the adhesives in the proper ratio of A:B is controlled by the metering
pumps.A stationary mount or gantry installation requires a swivel mounting bracket. To complete purging, turn the valve
with the mixer pointing up and dispense A & B.
Series 450 Autovalve / Snuff Back | Instructions / Parts Lists
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Maintenance
Two-component adhesives are messy and difficult to handle. It is important to note that routine maintenance must be
observed. If one delays maintenance until the valve stops, cleanup is very time consuming.
Routine Maintenance
1. Release pressures in A and B fluid hoses. Remove manifold and clean. We recommend overnight soaking in a suitable
solvent.
2. At the end of each shift, lubricate the back seals. We recommend auto grease. Pump auto grease through the grease
fitting (4) and out the plug (11). Using extra grease will extend seal life.
3. To clean the spool valves (75), first release the pressure on the A and B fluid hose. Then remove the manifold, and
advance the snuff-back adjustment (70) until the spool valves are protruding from the seat plate (8). With a toothbrush or
rag soaked in solvent, brush the spool valves clean. Protective eyeglasses should be used.
NOTE: With moisture sensitive urethanes or epoxies the spool valves must be cleaned. After cleaning, coat them spool
valves with auto grease.
4. The O-rings (6) and lip seals (3) are in a very harsh environment. In addition to resisting the adhesives, they must be inert
to the strong solvents used in cleaning the valve.
Installation
Connect Supply Lines
The A & B fluid hoses are connected to the side of the valve body (7), between the valve and the pumps, and should be as
short as possible. It is a good practice to install check valves in the hoses just before the valve.
For stationary mount, the air lines will be connected to the side of the air cylinder (1). Air to the front of the cylinder to close
and air to the back to open. If the optional handle is used, air is connected to the barbed fitting (105) on the side of the
handle.
The air line should have minimum pressure of 5.5bar (80psi).
Startup
With the hand-held model, start metering pumps and purge the air out of the A & B hoses and Autovalve. After the A and B
fluids come out of the manifold, attach a mixer to the manifold and hold the valve upside down with the mixer pointing up.
Dispensing A & B will purge the last pockets of air in the valve body.
A stationary mount or gantry installation requires a swivel mounting bracket. To complete purging, turn the valve with the
mixer pointing up and dispense A & B.
1. Take a ratio check by weight of A:B after the manifold. The Autovalve does No Metering. The Volume Ratio of A:B is
controlled by the metering pumps. However, between the metering pumps and the Autovalve are hoses. These hoses
will expand under pressure and cause lead-lag problems. Lead-lag refers to the uneven starting of the A fluid before the
B fluid. Nordson EFD offers 1:1 and wide ratio manifolds to reduce this problem. The selection of the correct manifold
depends on both the volume and viscosity ratio of A and B. Consult EFD Technical Services for details at 800-556-3484.
2. Adjust snuff-back screw (70) for minimum snuff-back. See page 12 of this manual for valve details.
Series 450 Autovalve / Snuff Back | Instructions / Parts Lists
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Maintenance (continued)
The following options are available:
A. Chemical Compatibility with O-Rings
Usually the adhesives do not chemically attack the O-rings. However, during cleaning the valves are often immersed in
aggressive solvents. The following types of O-rings are available:
Type of O-Ring Color Recommended for Contact With...
Viton
®
Green or brown
• Methylene Chloride
• Alcohol
• Carbon Tetrachloride
EP Black
• MEK
• Ketones
• Acetone
PTFE Clear / orange
• All chemicals
• Encapsulated
B. Selection of Lip Seals
The lip seal consists of a U-cup with an interior O-ring. The following types of lip seals are available:
• Polyurethane U-cup with an interior Viton O-Ring. Good general purpose seal with good chemical and wear resistance.
U-cup colored orange with a brown Viton O-Ring. Recommended for filled abrasive adhesives.
• Viton U-cup with an interior Viton O-Ring. Good chemical resistance, but it is a soft seal with poor wear resistance.
U-cup colored black with brown O-Ring.
• UHMPE U-cup and an interior SS Spring. Excellent chemical and wear resistance. U-cup colored white with SS Spring.
Other combinations available upon request.
C. Chemical Compatability
The “A” or “B” resins can attack the seal material. An attacked seal will swell or become brittle in 3 to 14 days. If this occurs,
choose an alternate seal material. Listed below are the general guidelines.
For specific recommendations for Meter Mix Dispensing, contact our Technical Service Department at 800-556-3484.
Part #7702281 (Polyurethane)
Color: Orange
Epoxies — General
Polyurethanes
Polysulfides
Part #7702277 (UHMPE)
Color: White
Epoxies — Amine Catalyst
Polyesters
Acrylics