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Dixon Quick Coupling

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1. Sketch the position of the tool, fittings, safety check and supply line. Measure the length of hose from the safety check to the

tool. There should be no jump sizes in the hose between the safety check and the tool. You will need one safety check

valve for each branch line feeding the tool. A safety check in the main supply line is also recommended.

2. Determine the hose size you want to protect. Select the same size safety check as the hose size. For example, a 3/8" hose

will require a 3/8" safety check. Do not use a different size safety check. One exception to this rule is for 5/8" hose, use a

1/2" safety check valve.

3. Determine the maximum operating air flow (SCFM) required through the safety check during normal use. For example, the

maximum air consumption of the largest tool used on that supply line. Determine the optimum cutoff flow by multiplying the

maximum operating air flow by 110%.

4. Add to the length of hose, you measured in step 1, length adders to compensate for system components. Add 0.91m (3') for

each elbow, 0.91m (3') for each tee, 3.05m (10') for each globe valve, 0.61m (2') for each gate valve, 0.91m (3') for each

hose fitting. This calculation will result in the total length for your safety check valve selection. Find the column in the

Unobstructed Air Flow Chart, on the next page, that corresponds to your hose size and the row that corresponds to your

calculated total length. Where they intersect, is the unobstructed air flow in SCFM.

5. If the optimum cutoff flow is 80% of the unobstructed air flow or less, you should use the optimum cutoff flow (110% of the

maximum calculated air flow) to select the appropriate safety check valve. To do this, find the safety check that has a

corresponding cutoff flow rate in the product list on the next page.

6. If the optimum cutoff flow is greater than 80% of the unobstructed air flow, there may be a problem with the safety check

valve sensing the difference between normal air demand and a line rupture. You may want to consider removing fittings

from the flow path, reducing the length of your hose or increasing your hose diameter. If you are not sure, call your

Dixon distributor for assistance.

7. Always install one safety check and test the performance of the system before you continue other installations. When start-

up is underway, open the air control valve at the compressor or manifold VERY SLOWLY to allow air to bleed through the

check valve so that pressure is equalized on each side of the valve. If the valve fails to operate despite meeting all

conditions, check the supply line for obstructions or a hose mender restricting normal air flow.

SCV-Series Selection Parameters

Not recommended for applications requiring 100% of the available air supply.

These applications include, but are not limited to, sand blast equipment, pile

driving rigs, and expansion joint blow down pipes.

It is recommended to install auxilliary safety devices, including Safety Cables,

to ensure optimum safety for the operator in the event of a coupling failure or

hose rupture.

SCV-Series

1/4"

3/8"

1/2"

3/4"

1"

1-1/4"

1-1/2"

2"

2-1/2"

3"

Operating

Bar (PSI)

Min. Burst

Bar (PSI)

Performance

Specifications

Temperature

°C (°F)

17 (250)

138 (2,000)

121 (250)

Air Flow *

30.5m (100')

17 SCFM

41 SCFM

77 SCFM

178 SCFM

340 SCFM

620 SCFM

940 SCFM

1,760 SCFM

2,800 SCFM

4,200 SCFM

• High flow design results in maximum flow with minimal pressure drop.

• Automatically and instantly protects the operator against hose whip in the

event of a damaged hose or coupling.

• In the event of a hose rupture or coupling failure, the valve will

automatically reset after the problem is fixed.

• SCV-Series is available in a large selection of sizes ranging from 1/4" to

3", NPTF or BSPP/BSPT threads.

• Valve operation is fully compliant with OSHA Safety Regulation

1926.302(b)(7), as shown on page 3.

* Air flow rating is based upon calculated values using unobstructed air

flow for the applicable hose size.

Attention Required!

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