Honeywell DC6, DC2, DC3, DC4, DC5 manual Check Valves, General Description

7.3Check Valves

7.3.1General Description

Most fluid metering problems are related to check valves. Problems usually stem from solids accumulation between valve and seat, corrosion of seating surfaces, erosion, or physical damage due to wear or the presence of foreign objects.

The valve incorporates a ball, guide, and seat. Flow in the unchecked direction lifts the ball off the seat, allowing liquid to pass through the guide. Reverse flow forces the ball down, sealing it against the sharp edge of the seat. The guide permits the ball to rotate but restricts vertical and lateral movement in order to minimize “slip” or reverse flow. Ball rotation prolongs life by distributing wear over the entire surface of the ball. Since ball return is by gravity, the valve must be in the vertical position in order to function properly. Parts are sealed by “O”-rings.

All OMNI models with the exception of the DC5 and 6 in metal construction utilize a convenient cartridge-type check valve. All check components are pre-assembled and the cartridge should be replaced as a unit. When replacing, note that valves are marked with the flow direction, as the suction and discharge configurations are different.

OMNI DC5 and 6 models supplied with metal (316ss) reagent head construction utilize a multi-part check valve assembly, secured to the reagent head with a tie-bar clamping arrangement. These utilize the same components (seat, ball, and guide) and operate in the same manner as the cartridge type.

Figure 9, check valves, DC2

Check Valve Suction Position

Check Valve Discharge Position

Figure 9, check valves DC2

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