Abstract: A method is provided for monitoring liquid flow in an open pipe or conduit wherein sensor means is located adjacent the invert or bed at the inside thereof and the depth of liquid is determined by the bubbler method. To minimize interferences with the liquid flow the bubble fluid is conducted from the exterior along the inside wall and to the vicinity of the flow bed in the pipe or conduit. The sensor means and the bubble fluid conductor are retainable in place by supporting means adapted to be expanded into secure frictional engagement with the inside wall of the pipe or conduit. The flow is determined by releasing the bubble fluid bubble-wise against the static pressure of the overlying liquid, sensing such pressure, indicating it in terms of liquid depth, and converting depth to flow by conventional methods.

Abstract: Liquid flow through a sewer or water pipe or conduit is measured by admitting the liquid into a confining region of known dimensions from an open end of the pipe or conduit at such rate as to maintain the liquid depth constant in the pipe or conduit and determining the volume of liquid entering the region within a given time period. The depth in the pipe or conduit is conveniently monitored as static pressure of liquid, as is the depth in the confining region. Air is educted from the confining region as necessary to ensure admission of the liquid thereinto at the desired rate for constant in-pipe depth.

Abstract: A probe adapted to fit in an open end of a sewer or water conduit is provided with a weir plate and with a bubble tube for sensing the depth of flow over the weir plate and, thus, determining the flow rate. A V-notch weir plate is made up of two like pieces flexibly joined at their apex, thereby enabling the probe to be compressed for ease of insertion into the open end and to be expanded therewithin for frictional retention against the inside wall of the conduit, to which the probe conforms. Except for the weir plate itself all parts of the probe lie along the wall for minimum disturbance of the flow. A gasket seals the weir plate to the inside wall of the conduit. A fisheye level on the probe facilitates vertical positioning of the weir plate.

Abstract: A stilling device, especially useful in large water or sewer pipes or conduits having overhead access openings, is provided in tubular T-shape. The base of the T conveniently comprises a plurality of telescoping sections adapted to be secured together at given extended length. Openings through one side of the T base in a direction perpendicular to the plane of the T facilitate equalization of liquid level inside with the surrounding level when immersed in a water or sewer pipe or conduit. The cross-bar of the T aids retention of the stilling device in place.

Abstract: A method and portable apparatus for continually monitoring the flow of fluid in an open channel such as in a conduit having a known diameter, a known slope and of material having known surface characteristics. The liquid depth within the pipe is determined by means of an elongated hollow probe placed axially in the bottom of a channel containing the liquid and forcing gas under pressure there through. The measurement of the back pressure represents the depth of the liquid and enables the rapid determination of the rate of flow. It is contemplated that the portable apparatus be interconnected with a portable continual recorder such that the flow may be monitored over any given, desired, time period.

Abstract: A probe adapted to fit in an open end of a sewer or water conduit is provided with a weir plate and with a bubble tube for sensing the depth of flow over the weir plate and, thus, determining the flow rate. A V-notch weir plate is made up of two like pieces flexibly joined at their apex, thereby enabling the probe to be compressed for ease of insertion into the open end and to be expanded therewithin for frictional retention against the inside wall of the conduit, to which the probe conforms. Except for the weir plate itself all parts of the probe lie along the wall for minimum disturbance of the flow.

Abstract: A method and portable apparatus for continually monitoring the flow of fluid in an open channel, such as in a conduit, having a known diameter, a known slope and of material having known surface characteristics. The liquid depth within the pipe is determined by means of an elongated hollow probe placed axially in the bottom of a channel containing the liquid and forcing gas under pressure there through. The measurement of the back pressure represents the depth of the liquid and enables the rapid determination of the rate of flow. It is contemplated that the portable apparatus be interconnected with a portable continual recorder such that the flow may be monitored over any given, desired, time period.