Xylem H-3551 - Manual (Page 5)

Chapter 1
Introduction
H-3551
Introduction 1-1
1.0 Introduction
The W
ATER LOG ® Model H-3551 is a self-contained "smart" gas purge system which produces a
precision, constant mass flow of gas. Together with a pressure measurement device, it is used to measure
fluid levels in applications such as surface water (streams and lakes, etc.), ground water and tanks.
The H-3551 uses a battery operated compressor to maintain pressure in an internal tank. An internal
microprocessor controller determines how much pressure is needed in the tank, based on the current head
pressure, to produce a constant bubble rate. Hence, the term "smart". The compressor and tank replace the
dry nitrogen tank used in previous systems.
The H-3551 uses a sophisticated system of sensors and valves to regulate the bubble rate and purge
pressure. This portion of the H-3551 replaces the sight feed flow controller and pressure regulator
(Conoflow system) used in previous systems.
The H-3551 is used primarily with the W ATER LOG ® Series Model H-350XL which performs several
different functions in the system: First, it is the precision pressure measurement source for measuring the
fluid level. This function replaces the manometer in previous systems. Second, it is the terminal through
which the H-3551 is configured. Third, it can be the data recorder for the system, thus removing the need
for an external data recorder.
The H-3551's provides a purge feature which temporarily pumps up the tank to a high pressure and opens a
valve to apply high pressure to the orifice line. This feature is designed to remove any sediment that may
have collected in or around the outlet of the orifice line.
1.1 Key Features
Following is a list of some of the H-3551's features:
! Provides a continuous gas flow
! Battery operated
! Microprocessor controlled
! One-piece manifold eliminates many potential sources of leaks
! Pressure gauge provides a visual indication of the tank pressure
! Hydrophobic intake membrane, protects compressor
! All components are easily accessible for inspection and maintenance
! Compressor does not have a “diaphragm”
! Provides an internal pressure relief valve
! Compressor is serviced and rated for cold temperature operation
! Can be optionally controlled and monitored as an SDI-12 “sensor”