Graco 24R021 Operation, Prime, Pressure Balance the Gun, Perform Pressure Relief Procedure on

Operation

Operation

Prime

Perform this procedure whenever air is introduced into the material lines, such as after connecting the material supply lines to the dispense valve.

1.Perform Pressure Relief Procedure on page 10.

2.If a static mixer is installed, remove static mixer.

3.Use lever (H) to open the dispense valve inlet ball valves (J).

NOTICE

Always open and close lever (H) fully and quickly. Opening the valve partially or slowly will cause soft spots in the material and may shut down the propor- tioner because of a pressure imbalance.

4.If necessary, prime the proportioner. See propor- tioner manual for priming instructions.

5.Run the proportioner until clean, air-free material begins to exit the dispense valve.

6.If necessary, Pressure Balance the Gun.

7.Install Disposable Static Mixer.

Pressure Balance the Gun

Balancing the back pressure:

•controls ratio lead-lag when the gun opens

•holds pressure in the hose, providing a very smooth flow

•minimizes oozing from mixer

•minimizes material crossover.

1.Use lever (H) to close the dispense valve inlet ball valves (J).

NOTICE

Always open and close lever (H) fully and quickly. Opening the valve partially or slowly will cause soft spots in the material and may shut down the propor- tioner because of a pressure imbalance.

2.Remove static mixer.

3.With the static mixer removed, dispense into a waste container. Note pressure gauge readings. If pressures are more than 25% apart, continue to next step. If not, pressures are sufficiently balanced.

4.If pressures are more than 25% apart, replace one or both plugs or restrictors with a different restrictor size:

NOTE: An extra 0.032 in. restrictor is included with the gun. If necessary, use this restrictor to balance the pres- sures. Put the larger orifice on the side with the higher viscosity material.

a.Perform Pressure Relief Procedure on page 10.

b.Select the new restrictors required to achieve desired back pressure and balance. See pres- sure drop chart in FIG. 2 on page 15.

NOTE: The valve should be able to achieve the desired flow rate at a pressure of 200-1500 psi (1.4-10 MPa,

14-103 bar). A (ISO) and B (RES) pressures should bal- ance within 25% of each other.

c.Install Restrictors or Plugs, see page 11.

d.Repeat this procedure to verify pressures are balanced.

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