Taylor-Wharton Auto Fill Laser Pak User Manual

Auto-Fill Laser Pak

Installation and Operation Manual

Product Part Number AF55-0C00

Revision A, May 8, 2006

Do not attempt to use or maintain these units until you read and understand these instructions. Refer to the Taylor­Wharton’s Safety First
maintain this equipment. If you do not understand these instructions, contact your supplier for additional information.

booklet (TW-202) for handling cryogenic material. Do not permit untrained persons to use or

______ Table of Contents

WARNING 3

Safety Precautions for Liquid Nitrogen 3

INTRODUCTION 4

System Description 4
Operation Sequence: Brief Overview 4

PIPING CIRCUITS 6

Vent to Bulk Circuits 7
Fill and Vent to Atmosphere Circuits 8
Pressure Building Circuits 9
Use Circuits 10
Safety Devices 11
Instrumentation Circuits 12

INSTALLATION 13

Handling 13
Pre-Installation Checks 13
Customer Installed Equipment/Piping 14
Electrical 15
Power 15
Error Alarm 15
Bulk Tank Pressure Line 16

OPERATION 17

Controller Operation 17
Graphic Terminal Operation 17
First Fill 19
Normal Operation 20
Long Duration Shutdowns 20
Restart 21
Error Conditions 21
Taking the Auto-Fill Laser Pak Out of Service 22

MAINTENANCE 23

Leak Test 23
Solenoid Valves 23
Safety Device Replacement 24
Instruments 24
Controller 24
Checking Vacuum 25
Trouble-Remedy Guide 26
Replacement Parts 28

APPENDIXES 29

Auto-Fill Laser Pak General Arrangement

Contoller, Auto-Fill Laser Pak

WARNING

The following safety precautions are for your protection. Before installing, operating, or maintaining this unit
read and follow all safety precautions in this section and in reference publications. Failure to observe all
safety precautions can result in property damage, personal injury, or possibly death. It is the responsibility of
the purchaser of this equipment to adequately warn the user of the precautions and safe practices for the use of
this equipment and the cryogenic fluid stored in it.

Safety Precautions for Liquid Nitrogen

Nitrogen is an inert, colorless, odorless, and tasteless gas making up four-fifths of the air you breathe. Liquid
nitrogen is obtained by cooling air until it becomes a liquid and then removing the oxygen. Air is roughly
one-fifth oxygen. Liquid nitrogen is at a temperature of -320°F (-196°C) under normal atmospheric pressure.

Extreme Cold - Cover Eyes and Exposed Skin
Accidental contact of liquid nitrogen or cold issuing gas with the skin or eyes may cause a freezing injury
similar to frostbite. Handle the liquid so that it won't splash or spill. Protect your eyes and cover the skin
where the possibility of contact with the liquid, cold pipes and cold equipment, or the cold gas exists. Safety
goggles or a face shield should be worn if liquid ejection or splashing can occur or cold gas can issue
forcefully from equipment. Insulated gloves that can be easily removed and long sleeves are recommended
for arm protection. Trousers without cuffs should be worn outside boots or over the shoes to shed spilled
liquid.

Keep Equipment Area Well Ventilated
Although nitrogen is non-toxic and non-flammable, it can cause asphyxiation in a confined area without
adequate ventilation. Any atmosphere not containing enough oxygen for breathing can cause dizziness,
unconsciousness, or even death. Nitrogen, a colorless, odorless, and tasteless gas, cannot be detected by the
human senses and will be inhaled normally as if it were air. Without adequate ventilation, the expanding
nitrogen will displace the normal air resulting in a non-life-supporting atmosphere.

Dispose of Waste Liquid Nitrogen Safely
Dispose of waste liquid nitrogen out-of-doors where its cold temperature cannot damage floors or driveways
and where it will evaporate rapidly. An outdoor pit filled with clean sand or gravel will evaporate liquid
nitrogen safely and quickly.

For more detailed information concerning safety precautions and safe practices to be observed when handling
cryogenic liquids consult CGA pamphlet P-12 "Handling Cryogenic Liquids" available from the Compressed
Gas Association, 1235 Jefferson Davis Highway, Arlington, VA 22202.

NOTE: Argon is an inert gas whose physical properties are very similar to those of nitrogen. For
handling of liquid argon, follow the safe practices described for the handling and use of liquid nitrogen.

CAUTION: The Auto-Fill Laser Pak is not designed for use in oxygen service.

3

INTRODUCTION

This manual provides information for the operation and maintenance of Taylor-Wharton's Auto-Fill Laser Pak
cryogenic liquid pressurization system. The Auto-Fill Laser Pak is intended for use in applications requiring
nitrogen or argon at pressures higher than possible from standard 175 or 250 psig cryogenic bulk tanks.

Cryogenic liquid is supplied to the Auto-Fill Laser Pak from a standard bulk tank. The Auto-Fill Laser Pak
“boosts” the liquid up to pressures as high as 450 psig. Once the pressure of the cryogenic fluid is raised to the
desired level, the Auto-Fill Laser Pak is capable of delivering liquid to a downstream vaporizer at gas
equivalent rates as high as 15,000 standard cubic feet per hour. The supply of product out of the Auto-Fill
Laser Pak is continuous even when the bulk tank is being filled.

Product specifications, flow diagram, views, and important dimensions are shown on the general arrangement
drawing, AF55-0C00_GA, provided in this manual.

System Description

The Auto-Fill Laser Pak consists of three groups of components: vessels, piping circuits, and
control/instrumentation. These components are assembled to a stainless steel frame for easy installation.

Two 196-liter vessels are included in the system. Each vessel consists of a pressure vessel suspended inside a
jacket. The space between the pressure vessel and the jacket is evacuated and insulated with a micro­fiberglass / aluminum foil radiation shield. The pressure vessel is designed and constructed in accordance
with the ASME Boiler and Pressure Vessel Code Section VIII, Division 1. Both the inner pressure vessel and
vacuum jacket are constructed of type 304 stainless steel.

The piping circuits allow the vessels to vent, fill, pressurize, and deliver cryogenic liquid to the vaporizer.
Eight solenoid valves, four for each vessel, control flow. Two high capacity pressure builders, one for each
vessel, use heat from ambient air to maintain pressure in the vessels. Piping is type-304 stainless steel. Valves
are brass. Weld and compression type fittings are type-316 stainless steel. Compression fittings are double
ferrule type. Screwed fittings are machined from forged brass. The pressure builders are constructed of
aluminum.

The controller is housed inside a NEMA 4X fiberglass enclosure. Instrumentation consists of two differential
pressure transmitters and three pressure transmitters. A differential pressure transmitter is piped to each of the
vessels in order to measure liquid level. Gauge pressure transmitters monitor pressure in each of the vessels
and the bulk tank. The bulk tank pressure transmitter is provided with the system. All wiring is in accordance
with the National Electrical Code.

The Auto-Fill Laser Pak pressurizes cryogenic liquid by adding heat to the liquid in a controlled fashion. All
energy for building pressure is provided by heat from ambient air. Electrical power is required only to operate
the controller, instruments, and solenoid valves.

Operation Sequence: Brief Overview

Consider the following starting conditions: vessel A is empty of liquid and filled with high-pressure gas;
vessel B is filled with liquid and pressurized. (See piping schematic on page 6.)

1. Liquid from vessel B is supplied at pressure to the vaporizer. Vessel B is in SUPPLY mode.

2. High-pressure gas from vessel A is vented back to the bulk tank. Vessel A is in VENTING TO
BULK mode. This feature minimizes product loss during filling.

4

3. Once the pressure in vessel A and the bulk tank are nearly equal, gas from vessel A is vented to the
atmosphere. Driven by the higher pressure in the bulk tank, liquid from the bulk tank flows into
vessel A. Vessel A is in FILLING mode.

4. When vessel A is full, venting to atmosphere stops. Pressure in vessel A is increased by boiling
liquid in the pressure builder and returning it to the top of the vessel as gas. Vessel A is in
PRESSURIZING mode.

5. Once pressure in vessel A reaches set point, flow through the pressure builder stops. Vessel A is in
STAND-BY mode.

6. During the filling and pressurization process of vessel A, vessel B has been supplying an
uninterrupted flow of high-pressure liquid to the vaporizer. Pressure in vessel B is increased as
necessary by the pressure builder.

7. When vessel B becomes empty of liquid, the system places vessel A in SUPPLY mode. Vessel B
begins the venting to bulk, filling, and pressurizing steps.

A more detailed explanation of the system operation is described in the next section, “Piping Circuits.”

5

PIPING CIRCUITS

b

The following paragraphs describe the operation of the piping circuits of the system. The descriptions refer to
the main components of each circuit and are grouped by function. Reference the piping schematic below and
in the general arrangement drawing for the component designations. Round stainless steel tags attached to the
system identify the components. Component tags ending with “A” identify components associated to vessel
A; tags ending with “B” identify components associated to vessel B. These component and circuit
descriptions should be understood before attempting operation.

PT-1A

PI-A

PT-2A

CN-1

PT-1B

BD-A RV-1A

PI-B

AF55-0C00 has a
strainer following the

ulk connection

PT-2B

RV-1B BD-B

V-7A

V-5A

V-6A

CV-3A

V-7B

V-5B

V-6B

CV-3B

CV-1A

V-1A

V-1B

CV-1B

V-2A

CV-2A

V-2B

CV-2B

V-3A

V-3B

Vessel “A”

V-4A

PB-A

CN-2

V-4B

Vessel “B”

PB-B

Legend

CN-1 Bulk Tank Connection PB Pressure Builder
CN-2 Vaporizer Connection V-1 Liquid Use Solenoid Valve
CV-1 Liquid Use Check Valve V-2 Vent to Bulk Tank Solenoid Valve
CV-2 Vent to Bulk Tank Check Valve V-3 Vent Solenoid Valve
CV-3 Fill Check Valve V-4 Pressure Building Solenoid Valve
BD Rupture Disc V-5 Liquid Phase Isolation Valve
PI Vessel Pressure Gauge V-6 Vapor Phase Isolation Valve
PT-1 Liquid Level Transmitter V-7 Equalization Valve
PT-2 Vessel Pressure Transmitter RV-1 ASME Relief Valve

PT-3 Bulk Tank Pressure Transmitter

Figure 1: System Piping Schematic

6

Vent to Bulk Circuits

Before filling occurs, the Auto-Fill Laser Pak recovers high-pressure gas in the vessels by returning it to the
bulk tank. The gas is vented from the top of the vessel through the vent to bulk solenoid valve (V-2). Gas
exits the system through the bulk tank connection (CN-1) and enters the bulk tank through the liquid
withdrawal line. The gas is recondensed as it bubbles through the liquid in the bulk tank. Venting to the bulk
tank occurs until the pressure in the vessels is less than the bulk tank pressure plus 25 psi.

Venting to the bulk tank also occurs during periods of little or no usage. Gas is generated over time due to
heat input to the inner vessel through the supports, piping, and insulation. This gas is recovered by venting it
back to the bulk tank through the same circuit described above. This occurs when the pressure in the vessels
exceeds a user adjustable set point. This is similar to the “economizer” feature found on bulk cryogenic
vessels.

The user can deactivate these features by setting a controller parameter. This is described in the controller
operation section of this manual.

V-2A

CV-2A

CN-1

Figure 2: Vent to bulk circuit for vessel A highlighted in blue.

(Frame and wiring omitted from view for clarity.)

7

Fill and Vent to Atmosphere Circuits

Filling a vessel with liquid from the bulk tank occurs by pressure transfer. The pressure in a vessel is reduced
by venting gas from the top of the vessel to the atmosphere through the vent solenoid valve (V-3). A muffler
connected to the vent valve outlet keeps noise to a comfortable level. Liquid flows from the bulk tank,
through the liquid withdrawal line, and into the system through the bulk tank connection (CN-1). Liquid
flows through the fill check valve (CV-3) and into the vessel.

Note that filling occurs anytime the pressure in a vessel is less than that of the bulk tank.

V-3A

Muffler

CV-3A

CN-1

Figure 3: Fill and vent to atmosphere circuit for vessel A highlighted in blue.

(Frame and wiring omitted from view for clarity.)

8

Pressure Building Circuits

A pressure building circuit serves to build pressure after filling a vessel. The circuit is also used to ensure
sufficient driving pressure during product withdrawal periods. The controller opens the pressure building
solenoid valve (V-4) that creates a path from the liquid in the bottom of the container to the gas space in the
top. This path contains a pressure-building coil (PB) to vaporize product as it flows from the bottom to the top
of the vessel. Liquid is expanded to a vapor and pressure is increased in the vessel.

V-4B

PB-B

Figure 4: Pressure building circuit for vessel B highlighted in blue.

(Frame and wiring omitted from view for clarity.)

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