Section 3.2 Valve Systems
Counterbalance and cushion systems are very similar in the way they are controlled. Three basic integrated valve configurations are available from Link to be used with the OmniLink 5000 ASM. For clarity in the following sections, these valve configurations are defined here.
Type “A” An integrated Fill/Dump Valve as shown in Figure 3.2. This valve has the advantage of simple straight through piping with all pilot pressures run internally and is easily mounted. It may be used for air cushion and air counterbalance control. This is the least expensive of the three valves. Leaks in cushion and counterbalance systems will cause loss of pressure in these systems when either control power is off or supply pressure is absent. However, the control must be turned back on and pressure
Figure 3.2: Type “A” Valve Configuration
Type “B” An integrated Fill/Dump valve with a manual regulator, check valve, and LOX valve in parallel as shown in Figure 3.3 for cushion, but not counterbalance, adjustment. This valve adds a parallel manual regulator system to the Type “A” valve, which may be set to prevent the air pressure in the cushion from going below a minimum value set by the manual regulator (as long as there is shop air pressure). This prevents cushion drift down when control power is off with its associated lost die pins below the press bolster and lost time while they are recovered. This valve also allows the cushions to be adjusted using the manual regulator path if the automatic system fails, allowing the press to be operated until the automatic system is restored. When the automatic system is on, the manual regulator on this valve system must not be set higher than the lowest pressure that the automatic system is to provide, because the automatic valves will try to dump while the manual regulator fills if the automatic setpoint is lower than the manual regulator pressure.
Figure 3.3: Type “B” Valve Configuration
April 17, 2000 Man ual Versio n 1.0 | 3.3 |