Graco 262893 important safety instructions Volume Balancing the Mix Manifold, Lead/Lag Imbalance

Volume Balancing the Mix Manifold

Ratio errors can occur between the sprayer and the mix manifold even when the sprayer output ratio is accurate.

The following can occur when the hoses are not volume balanced to the mix ratio:

•Hoses fill to high pressure while metering on-ratio.

•Only the A material hose rises to spray pressure.

•Off-ratio at the mix point until hose pressures equal- ize.

Lead/Lag Imbalance

When resin and hardener volume requirements (ratio) and/or viscosities are different an imbalance can occur each time the gun is triggered. This occurs because the fluids can rush out of the manifold near a 1:1 ratio before the sprayer starts.

To avoid this imbalance:

•Pressurize hoses to spray pressure before starting spray mode.

•Size the fluid delivery hose volume to nearly match the mix ratio. See Table 1.

Operation

Hose Selection

Hoses should be sized to match the hose volume ratio to the mix ratio. The hose size should also allow for min- imum pressure drop on the major volume side to meet your flow requirements.

Use Table 1 to match mix ratio, hose selection, and vol- ume ratio. Use Table 2 on page 14 to reference amount of pressure drop for 50 ft lengths of different hose sizes.

Size hoses to:

•Minimize pressure drop on the high volume and often higher viscosity resin side to achieve higher flow and pressure at the gun while spraying.

•Allow both A and B material hoses to come up to spray pressure together when A and B fluids are metered into the hoses on ratio.

•Balance the inherent stall pressure between the resin A and hardener B sides when the gun closes and also when triggered. This reduces the lead/lag error at the mix point when the spray gun is trig- gered.

Table 1: Volume Ratio of A to B Hose

Example: At a 4:1 mix ratio, a 1/2 in. ID resin hose and a 1/4 in. ID hardener hose matches the 4:1 volume ratio.