Nordson-EFD-Series-450-Instructions - 第5页

Series 450 Autovalve / Snuff Back | Instructions / Parts Lists 5 www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide. Maintenance (continued)…

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-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 5.5bar (80psi).

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

5www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide.

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

Series 450 Autovalve / Snuff Back | Instructions / Parts Lists

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Disassembly And Cleaning

1. Remove the manifold and seat plate (8). Pry bar slots are provided.

2. Remove the air cylinder bolts (2) and wiggle the air cylinder apart. If

the assembly is frozen, use the pry bar slots on the valve body (7) to

separate the valve body (7) from the tie plate (5). Insert ﬂat pieces of

metal between the valve body and the tie plate as per Figure 1. Thread

the manifold screws (36) into the back of the tie plate and push the

valve body apart. Apply uniform pressure to prevent the body from

cocking and bending the spool valves (75).

3. Once apart, the parts should be cleaned. We recommend overnight

soaking in suitable solvent. All parts can be soaked except the handle

and air cylinder.

Rebuilding the Autovalve

1. After cleaning, inspect the following components:

a. Spool valves (75) for wear

b. Lip seals (3) — both outside and inside lip

c. Manually retract and extend spool valves from air cylinder (1).

d. If the optional handle is used, connect air into the inlet and check 4-way action of cartridge valve (103).

2. Lubricate lip seals (3) and shafts (75) with auto grease.

3. Insert four back lip seals (3): two into tie plate (5) and two into the valve body (7). The lip seals are two piece: an O-Ring

and U-cup. They should always be installed with the O-Ring facing the material inlets (body of the valve).

4. Insert two front lip seals (3) that are located in the seat plate (8). They should be installed with the O-Ring facing the back

of the valve (facing the air cylinder). Optional Installation: With O-Ring facing manifold. Used when minimum snuff-back

is required. However, reduced seal life can be expected.

5. Insert O-Rings (6) and assemble air cylinder (1) and valve body (7). and the valve body (7) and engage the screws (2).

6. Push seat plate (8) through spool valves (75) and tighten bolts (9).

Final QC Check

Before the manifold is assembled, we recommend the following procedure:

1. Check the open and close movement of the spool valves (75).

2. Check gap between seat plate (8) and spool valve (75). Refer to Figure 2 when spool valves are in open position.

3. Check front lip seals by pressurizing the valve body (7) and applying soapy water into the front seals. The valve body can

be pressurized by connecting air into the A and B inlet ports on the valve body.

4. Seat plate (8)

Manifold

screws

Tie plate

Metal

plate

Air cylinder

Valve body

Figure 1

Maintenance (continued)