# Determine LRV and URV settings for the Level Transmitter

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#### Query :

Decide the LRV and URV settings for the water seal drum stage transmitter (LT-21), assuming the LRV level is on the decrease nozzle and the URV level is on the higher nozzle (the 2 nozzles being three ft eight inches aside from one another), and that the distant seal fill fluid has a particular gravity of zero.934:

The elevation for this transmitter (i.e. the full differential strain utilized by the peak of fill fluid on either side) is the same as the overall top distinction between the distant seal diaphragms multiplied by the particular gravity of the fill fluid:

Pelevation = (44 in)(zero.934) = 41.1 ”WC

Within the LRV situation, that is the one stress seen by the transmitter. Due to this fact, 41.1 ”WC is the suitable LRV setting for this transmitter. If we assume that the “H” port of this DP transmitter connects to the decrease nozzle, the LRV will likely be -44.1 ”WC. If we assume the “H” port connects to the higher nozzle, the LRV will probably be +41.four ”WC.

Within the URV situation, we now have the very same quantity of elevation (the fill fluid contained in the capillary tubes) however on the decrease nozzle we have now the hydrostatic stress of 44 vertical inches of water (i.e. the water contained in the seal drum). Thus, within the URV situation the transmitter sees a differential strain of:

Pdifferential = 44” WC − 41.1 ”WC = 2.9 ”WC

If we assume the “H” port of this DP transmitter connects to the decrease nozzle, the URV can be +2.9 ”WC.

If we assume the “H” port of this DP transmitter connects to the higher nozzle, the URV might be -2.9 ”WC.

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