Follower Pointer – the Simple Solution
A simple, low-cost follower pointer can be added to the differential pressure gauge to allow the troubleshooter to identify the problem. A follower pointer is red in color while the DP range pointer is normally black. During set up the user sets the red follower pointer against the black DP range pointer and walks away. The follower pointer itself is an assembly that includes the lens and red pointer with a small knob to set the position of the red pointer.
During operation the black DP pointer pushes the follower pointer to the highest reading but the follower pointer does not follow it back down the scale if the differential pressure drops. It will always remain at the highest differential pressure reading until it is reset.
If filter blow-by occurs the red follower pointer would have been pushed to the highest differential pressure reading experienced since the last visit. Even if the black DP range pointer is showing normal range of operation the follower pointer can indicate an alarm condition by being in a much higher position than the black DP range pointer. This separation of the black and red pointer immediately signals the troubleshooter that closer inspection is required.