American Magnetics 110 User Manual

EXCELLENCE IN MAGNETICS AND CRYOGENICS

MODEL 110A LIQUID HELIUM

AMI

LEVEL MONITOR

INSTALLATION, OPERATION, AND

MAINTENANCE INSTRUCTIONS

American Magnetics, Inc.

PO Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, Tel: 865 482-1056, Fax: 865 482-5472

Rev. 5, June 1999

Declaration of Conformity

Application of Council Directives: Low Voltage Directive 72/23/EEC

EMC Directive 89/336/EEC

Manufacturer’s Name: American Magnetics, Inc.

Manufacturer’s Address: 112 Flint Road,

P.O. Box 2509 Oak Ridge, TN 37831-2509 U.S.A.

Type of Equipment: Liquid Level Instruments Model Numbers: Model 110A

Standar ds to which Conformity is Declared:

Safety: EN 61010-1 (1993) w/A1, A2 EMC: EN55011 (1991) Group 1, Class A

EN50082-1 (1997) / EN61000-4-2 (1995) 8kV AD, 4kV CD EN50082-1 (1997) / EN61000-4-3 (1996) 3V/m EN50082-1 (1997) / EN61000-4-4 (1995) 1kV Power Supply

0.5kV I/O cables EN50082-1 (1997) / EN61000-4-5 (1995) 2kV CM, 1kV DM EN50082-1 (1997) / EN61000-4-6 (1996) 3V EN50082-1 (1997) / EN61000-4-11 (1994) Voltage dips 30% - 10ms

Voltage dips 60% - 100ms Short interruption >95% - 5s

I, the undersigned, hereby declare that the equipment specified above complies with the requirements of the aforementioned Directives and Standards and carries the "CE" mark accordingly.

Gregory J. Laughon September 12, 2002 Quality Assurance Manager

American Magnetics, Inc. Oak Ridge, TN, U.S.A.

1.1

Model 110A Features

................................................................

1.2

Model 110A Front Panel Layout

..............................................

1.3

Model 110A Rear Panel Layout

................................................

1.4

Model 110A Specifications @ 25

°C..........................................

2.1

Unpacking the Instrument

.......................................................

2.2

Rack Mounting the Instrument

................................................

2.3

Preparing the Sensor for Connection

.......................................

2.4

Connecting any Communications Option

................................

2.5

Connecting the Instrument to Power

.......................................

3.1

Normal Operational Mode

........................................................

3.2

Contaminated Sensors

..............................................................

4.1

Troubleshooting Procedures

...................................................

4.2

Custom Instrument Configurations

.......................................

4.3

Additional Technical Support

.................................................

4.4

Return Authorization

..............................................................

A.1

4-20 ma Current Loop Option

.................................................

A.2

Sensor/Analog Outputs Connector J1 Wiring

........................

1 Introduction.............................................................................. 1

2 Installation................................................................................ 5

3 Operation.................................................................................. 9

4 Service Guide......................................................................... 11

Appendix................................................................................. 17

Index........................................................................................ 19

Table of Contents

Foreword

This manual contains the operation and maintenance instructions for the

American Magnetics, Inc. Model 110A Liquid Level Monitor. The manual

outlines the instructions for instrument use in typical system designs.

Since it is impossible to cover all possible system/sensor designs, the most

common configuration is discussed and the user is encouraged to contact

an authorized AMI Technical Support Representative for infor mat i on

regarding specific configurations not explicitly covered in this manual.

Introduction

introduces the reader to the functions and char acteristics of

the instrument. It provides the primary illustrations of the front and rear

panel layouts as well as documenting the performance specifications.

Installation

describes how the instrument is unpacked and installed in

conjunction with ancillary equipment in a typical cryogenic system.

Operation

describes how the instrument is used to measure liquid level.

Service

provides guidelines to assist Qualified Service Personnel in

troubleshooting possible system and instrument malfunctions.

Information for contacting AMI Technical Support personnel is also

provided.

The

Appendix

documents the rear panel con n e ctors.

Purpose and Scope

Contents of This Manual

iii

Foreword

The Model 110A has been designed t o opera te with an AMI Li quid Helium

Level Sensor. Operation with other equipment is not recommended and

may void the warranty.

Personnel handling cryogenic liquids should be thoroughly instructed and

trained as to the nature of the liquids. Training is essential to minimize

accidental spilling. Due to the coldness of these materials, a cryogen

spilled on many objects or surfaces may damage the surface or cause the

object to shatter, often in an explosive manner.

Inert gases released into a confined or inadequately ventilated space can

displace sufficient oxygen to make the local atmosphere incapable of

sustaining life. Cryogenic liquefied gases are potentially extreme

suffocation hazards since a small amount of liquid will vaporize and yield

a very large volume of oxygen-displacing gas. Always ensure the location

where the cryogen is used is well ventilated. Breathing air with

insufficient oxygen content may cause unconsciousness without warning.

If a space is suspect, purge the space completely with air and test before

entry. If this is not possible, wear a forced-air respirator and enter only

with a co-worker standing by wearing a forced-air respirator.

Cryogenic liquids, due to their extremely low temperatures, will burn the

skin in a similar manner as would hot liquids. Never permit cryogenic

liquids to come into contact with the skin or allow liquid nitrogen to soak

clothing. Serious burns may result from careless handling. Never touch

uninsulated pipes or vessels containing cryogenic liquids. Flesh will stick

to extremely cold materials. Even nonmetallic materials are dangerous to

touch at low temperatures. The vapors expelled during the venting process

are sufficiently cold to burn flesh or freeze optic tissues. Insulated gloves

should be used to prevent frost-bite when operating valves on cryogenic

tanks. Be suspicious of valves on cryogenic systems; the extremes of

temperature they undergo causes seals to fail frequently.

In the event a person is burned by a cryogen or material cooled to

cryogenic temperatures, the following first aid treatment should be given

pending the arrival and treatment of a physician or other medical care

worker:

If any cryogenic liquid contacts the skin or eyes, immediately flush

the affected area gently with tepid water (102°F

105°F, 38.9°C

40.5°C) and then apply cold compresses.

Applicable Hardware

General Precautions

Cryogen Safety

−

Foreword

Do not apply heat. Loosen any clothing that may restrict

circulation. Apply a sterile protective dressing to the affected area.

If the skin is blistered or there is any chance that the eyes have

been affected, get the patient immediately to a physici an for

treatment.

Containers of cryogenic liquids are self pressurizing (a s the liquid boils off,

vapor pressure increases). Hoses or lines used to transfer these liquids

should never be sealed at both ends (i.e. by closing valves at both ends).

When pouring cryogenic liquids from one container to another, the

receiving container should be cooled gradually to prevent damage by

thermal shock. The liquid should be poured slowly to avoid spattering due

to rapid boil off. The receiving vessel should be vent ed during the transfer.

Introduction of a substance at or near room temperature into a cryogenic

liquid should be done with great caution. There may be a violent gas boil

off and a considerable amount of splashing as a r esult of this rapid boi ling.

There is also a chance that the material may crack or catastrophically fail

due to forces caused by large diffe rences in ther mal contrac tion of differe nt

regions of the material. Personnel engaged in this type of activity should

be instructed concerning this hazard and should always wear a full face

shield and protective clothing. If severe spraying or splashing could occur,

safety glasses or chemical goggles along with body length protective

aprons will provide additional protection.

The properties of many materials at extremely low temperatures may be

quite different from the properties that these same materials exhibit at

room temperatures. Exercise extreme care when handling materials cooled

to cryogenic temperatures until the properties of these materials under

these conditions are known.

Metals to be used for use in cryogenic equipment application must posses

sufficient physical properties at these low temperatures. Since ordinary

carbon steels, and to somewhat a lesser extent, alloy steels, lose much of

their ductility at low temperature s, they are considered unsatisfactory and

sometimes unsafe for these applications. The austinetic Ni-Cr alloys

exhibit good ductility at these low temperatures and the most widely used

is 18-8 stainless steel. Copper, Monel

, brass and aluminum are also

considered satisfactory materials for cryogenic service .

Cryogenic storage systems are complex systems with the potential to

seriously injure personnel or equipment if not operated according to

procedures. Proper use of safety mechanisms (pressure relief valves,

Safety Summary

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