DeZurik APCO CAC-8000 Istruzioni - Pagina 6
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DeZURIK
APCO CAC-8000 Automatic Control Check Valve
Operation
Check Valve Function
The gap between the contact surfaces of the wormwheel and gear segment is called the "slip gear
travel". This slip gear allows the check valve feature to function. Operating as a Check Valve the
dashpot cylinder assembly fully controls disc movement with the adjustability to open/close timing to
suit the installation, thereby controlling the pressure surges and water hammer. The dashpot has three
adjustable controlling stages:
1. The primary control is the Timing Valve (#96).
2. The secondary control is the Flow Control Valve (No. 64, Fig. 2).
3.
The third controlling stage is located in the cylinder and provides additional control over the last
10% of disc travel. The top Flow Control Valve controls rate of opening while the bottom one
controls rate of closing. The dashpot cylinder is self-contained and uses oil as a controlling
media, creating a completely closed system which eliminates potential problems of corrosion,
electrolysis and mineral deposits, all too often present in water operated dashpots.
D12000
Figure 2: Check Valve Function
Page 6
December 2012