Two types of maintenance for Fisher valve positioners

Fisher valve positioner in the use of common adjustment methods will appear error, because its zero spring working in the linear area, its length change range is limited, and the range adjustment mechanism its mechanical position is limited, so the length of the zero spring and the range adjustment mechanism amplification factor value will be limited. So what should we do when we zero out the locator?

When the Fisher valve positioner commonly used adjustment method fails, we can adjust the parameters are the effective length of the feedback lever and the elastic coefficient of the zero spring, because the zero spring often works in the linear region, so here only discuss by changing the effective length of the feedback lever to verify the pneumatic valve positioner. We can connect the pin on the valve stem near the pneumatic valve positioner, so that the effective length of the feedback lever is shortened, that is, the effective length of the feedback lever is reduced, the L is increased, and the stroke is increased, and on the contrary, the effective length of the feedback lever is increased, and the stroke is reduced.

Preventive maintenance – According to the past production process experience, in order to prevent the occurrence of regulator accidents, it is necessary to arrange some regulator maintenance or repair. However, because there is no much information about the regulating valve used in the field, although some regulating valve accidents can be avoided, the arrangement cannot avoid causing some regulating valves to work normally and are also arranged in the overhaul ranks, and some unsuitable regulating valves are still used in the process control system.

Passive maintenance – When the regulator fails, repair the regulator. In the process of use, the regulator itself or some accessories fail, resulting in the regulator can not work normally, the more serious situation leads to the whole system can not work normally, resulting in a lot of accidents, so we need to carry out timely maintenance of the positioner.