Hach AV9000 Manuel D'utilisation page 6

Confined spaces are not designed for human occupancy. Confined spaces have a restricted entry
and contain known or potential hazards. Examples of confined spaces include manholes, stacks,
pipes, vats, switch vaults and other similar locations.
Standard safety procedures must always be obeyed before entry into confined spaces and/or
locations where hazardous gases, vapors, mists, dusts or fibers can be present. Before entry into a
confined space, find and read all procedures that are related to confined space entry.
2.2 Product overview
The submerged area velocity (AV) sensor is used with Sigma flow meters, FL series flow loggers and
AS950 samplers to measure the flow rate in open channels. Refer to
The sensor is available in oil-filled and non-oil-filled versions. The non-oil sensor is used for
reasonably clear sites, or sites where the pipe may become dry. The oil-filled sensor is used for sites
with high levels of biological growth, grit or silt.
Note: Do not use an oil-filled sensor in a pipe that may become dry.
The submerged AV sensor connects to a FL series flow logger or AS950 sampler through an
AV9000 interface module. Refer to
applicable AV9000 model for the flow logger or sampler.
Note: The submerged AV sensor connects directly to Sigma flow meters. An AV9000 interface module is not
necessary.
Figure 1 Submerged area velocity sensor
1 Junction box (optional)
2 Desiccant hub
3 Desiccant container
4 Air reference tube
5 Connector
2.3 Theory of operation
The sensor operates as an area velocity sensor and follows the continuity equation.
Flow rate = wetted area x average velocity
6 English
Replacement parts and accessories
6 Lanyard
7 Submerged AV sensor
8 Carabiner clip
9 Sensor cable
Figure 1.
on page 20 to identify the