Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions (say from no-flow to flow) within a series of relief flowlines to pinpoint sources of plant upset, is achieved by carefully positioning (in each flowline closely adjacent to an associated relief valve) a transducer-meter for sensing transient heat flux from a selected location completely exterior of the line; and recording in sequence: (i) a base line signal indicative of a no-flow, steady state condition at each selected location along the flowline, and (ii) a transient signal indicative of a flow condition. Both types of signals are generated by a plurality of thermocouples (a thermopile) attached to each flowline in a heat flux sensing relationship that takes into account the type of fluid being monitored and the temperature gradient existing across the relief valve.

Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions (say from NO-FLOW-to-FLOW) within a series of flowlines to pinpoint sources of plant upset is achieved, by carefully positioning a series of M transducer-meters for sensing transient heat flux, each meter being disposed at a selected location completely exterior of a flowline, and recording in sequence at a central control center for each of the M meters at least a transient signal indicative of a FLOW condition. For each meter, signals are generated by a thermopile attached to each flowline in a heat flux sensing relationship. Location takes into account the type of fluid being monitored, and the temperature gradient existing across the relief valve. Recordation of the sensed signals is via a series of M recorders and alarm circuits at the control center.

Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions, say from flow-to-no flow within a flowline of a wellhead connected to an oil well penetrating an earth formation, is surprisingly useful in pinpointing the occurrence of adverse "pump pounding" during the production cycle of the well. In one respect, the change in flux is monitored within each flowline using a heat flux transducer/meter in series with a pump controller. Cascading the signal output, i.e. serially combining the outputs of N thermocouples the transducer/meter, enhances sensitivity. In a preferred case, N is about 80 but can be as high as 320, if desired.

Abstract: Transient change in heat flux due to ultrasmall variation in flow conditions (say from no flow-to-flow) within a series of relief flowlines forming a component part of a flaring system associated with a chemical or refinery complex, is surprisingly useful in pinpointing a source of plant upset. Result: corrective action can be undertaken. In one aspect, the change in flux is monitored within each major relief flowline using a heat flux transducer-meter in series with signal indicating means, such as a recorder and/or an audio-alarm system. Cascading the signal output, i.e., serially combining the outputs of N thermocouples of the transducer-meter, enhances sensitivity. In a preferred case, N is about 80 but can be as high as 320, if desired.

Abstract: Transient change in heat flux due to a small variation in flow conditions (say from no flow-to-flow or vice versa) within a fluid-carrying body under a variety of conditions, is indicated. Ultrasensitivity is achieved by cascading the signal output of a plurality of N thermocouples (i.e., a thermopile), attached to upper and lower metallic plates of a heat flux transducer-meter, the upper plate being in heat transfer contact with at least a sector of the previously-mentioned fluid-carrying body. In a preferred case, N is about 80 but can be as high as 320, if desired. Recordation of the output signals is via a recorder, although use of an audio-alarm to immediately alert an operator of a change in flow conditions, contemplated.