Netherlocks Successful in ACHEMA 2003
28 May 2003
In the ACHEMA exhibition in Germany, Netherlocks, specialist in valve locking systems – machine guarding – lock out units and valve control, showed their latest developments.
PARTIAL STROKE TESTING
Especially to visitors interest was the particial stroking test devices. Two versions were shown: the mechanical FAITH system – and the diagnostic SMRT system.
The first is a mechanical device, which is mounted between the valve and actuator. The advantages are the simplicity, the absence of wiring and software and the assures that the actuator is not able to fully close the valve. The system is highly reliable, commercially attractive and immediately applicable.
The second mentioned is a diagnostic system, which is mounted directly into the power supply upstream the actuator. Before the system, called SMRT, will be active, the actuator is strokes ones to create a reference output curve. The curve indicates response time solenoid valve, quick exhaust and actuator. From this initial curve is determined how long the solenoid valve should be de-activated to create a partial stroke. Now, after each partial stroke test the condition of the SOV, QEV and actuator can be evaluated. Each test can be done from the control room and is automatically filed, which is fully in accordance to the IEC 61508.
INTERLOCKING UNITS
In spite integral locks are widely used by all major operating companies, still many engineers were not familiar with this phenomenon. Again was explained that mechanical trapped key interlocks exclude human error for the fully 100%. The system is simple; on each item that belongs to a critical sequence an interlock is mounted. This is done without any modification to the host equipment, even while the process is in production. The interlock unit contains keys that are trapped or freed, depending on the status of the switchover unit. When all locks are mounted onto the devices belonging to one sequence one starting key remains free. The free key makes it possible to unlock the fist device in the switchover procedure. After operating this, the first key is trapped, while a second key can be freed, which is necessary to unlock a second device. The steps continue until the procedure is finished.
All visitors understood that nothing really changes in the actual switchover procedure, however, they recognized that human error, caused by stress or distraction, is eliminated. After the Netherlocks engineer had explained the special Netherlocks MPCU box it was understood that the number of applications is infinite.
MANUAL GATE VALVE POSITIONING
The instrumentation and electrical engineers recognized in the Netherlocks VPI/Posimech the ultimate solution for their gate valves that require limit switches. Limit switches are often added to valves to create a feedback signal. This feedback signal is usually used to start another device, such as a pump.
Looking at the often used method of mounting switches to gate valves, welded bracket – extended spindles – loose wiring, we recognize that this is a source of irritation, maintenance and unnecessary costs.
The Netherlocks VPI/Posimech is a device that is integrally mounted to the valve. It is strong, has no loose wiring and above this gives a reliable signal.
MOBILE PNEUMATIC ACTUATOR
Often as final point of the stand tour the mobile pneumatic actuator was demonstrated. Especially the operators recognized the advantages. Normally it could take hours to operate a large manual gate valve from open to close or visa versa. The Netherlocks KMS reduces the operating time to 20%. However, another important advantage is the fact that this KMS reduces strain on the operator, which reduces illness.
