Generating two pneumatic signals to operate an actuator on a valve assembly
A controller configured to improve response time on a valve assembly. The controller may have flow modifying structure that couples with a pair of pneumatic outputs, both pneumatically coupled with an actuator on the valve assembly. The flow modifying structure can be configured to convert incoming instrument air into a pair of independent, pneumatic output signals, at least one of which flows directly to the actuator. In one implementation, a volume booster may be used to increase pressure of the other pneumatic output signal upstream of the actuator.
1. A valve assembly, comprising:
a valve with a closure member moveable relative to a seat;
an actuator coupled with the valve to move the closure member; and
a controller pneumatically coupled with the actuator via a first pneumatic output and a second pneumatic output, one of which couples directly with the actuator, the controller comprising a pneumatic amplifier with a pair of pneumatic relays, one each coupled with the first pneumatic output and the second pneumatic output, and a volume booster interposed between one of one of the pneumatic relays and the actuator,
wherein the pair of pneumatic relays use a pneumatic input signal at a first pressure to convert incoming instrument air into a pair of pneumatic output signals at a second pressure that is higher than the first pressure.
2. The valve assembly of claim 1 , wherein the second pressure is the same for both of the pneumatic output signals.
3. The valve assembly of claim 1 , further comprising:
a bypass that diverts fluid around the volume booster.
4. The valve assembly of claim 1 , wherein the volume booster comprises an adjustment that is configured to direct fluid around the volume booster.
5. A valve assembly, comprising:
a valve with a closure member moveable relative to a seat;
an actuator coupled with the valve to move the closure member; and
a controller pneumatically coupled with the actuator via a first pneumatic output and a second pneumatic output, one of which couples directly with the actuator, the controller comprising a pneumatic amplifier with a pair of pneumatic relays, one each coupled with the first pneumatic output and the second pneumatic output, and a volume booster interposed between one of one of the pneumatic relays and the actuator,
wherein the pair of pneumatic relays use a pneumatic input signal at a first pressure to convert incoming instrument air into a pair of pneumatic output signals at a second pressure that is proportional to the first pressure.
6. The valve assembly of claim 5 , wherein the second pressure is the same for both of the pneumatic output signals.
7. The valve assembly of claim 5 , further comprising:
a bypass that diverts fluid around the volume booster.
8. The valve assembly of claim 5 , wherein the volume booster comprises an adjustment that is configured to direct fluid around the volume booster.
9. A valve positioner, comprising:
a signal converter;
a pneumatic amplifier pneumatically coupled downstream of the signal converter, the pneumatic amplifier comprising a first pneumatic relay and a second pneumatic relay;
a pair of output ports, one each coupled downstream of the first pneumatic relay and the second pneumatic relay; and
a volume booster coupled downstream of one of the pair of outputs,
wherein the first pneumatic relay and the second pneumatic relay are configured to use a pneumatic input signal from the signal converter to convert incoming instrument air into a pair of independent, pneumatic output signals, one each to flow to the pair of output ports.
10. The valve positioner of claim 9 , further comprising:
a main board coupled with the signal converter, wherein the main board is configured to generate current to operate the signal converter in response to a control signal.
11. The valve positioner of claim 9 , wherein the pair of independent, pneumatic output signals exits the pair of output ports at a pressure that is proportionally higher than the pressure of the pneumatic input signal.
12. The valve positioner of claim 9 , wherein the pair of independent, pneumatic output signals exits the pair of output ports at pressure that is the same.
13. The valve positioner of claim 9 , further comprising:
a bypass that diverts fluid around the volume booster.
14. The valve positioner of claim 9 , wherein the volume booster comprises an adjustment that is configured to direct fluid around the volume booster.
15. A method, comprising:
receiving an electronic control signal;
generating a pneumatic input signal in response to the electronic control signal;
using the pneumatic input signal to convert instrument air into a pair of pneumatic output signals;
using the pair of pneumatic output signals to operate an actuator to move a valve; and
flowing one of the pair of pneumatic output signals through a volume booster to increase pressure upstream of the actuator.
16. The method of claim 15 , wherein the pneumatic input signal is at a first pressure and the pair of pneumatic output signals are at a second pressure that is proportionally higher than the first pressure.
17. The method of claim 15 , wherein the pair of pneumatic output signals are at pressure that is the same.
18. The method of claim 15 , further comprising:
tuning output of the volume booster with a bypass that diverts fluid around the volume booster.