Attachment 3 - TO 36G2-3-1.pdf

TO 36G2-3-1

TECHNICAL MANUAL

OPERATION, SERVICE AND REPAIR INSTRUCTIONS

AIR PURGING UNIT TYPE GSU-62/M

FEDERAL STOCK NUMBER

3655-987-2586

MANUFACTURER’S PN

(RANDALL)

F41608-87-D-A288

This publication supersedes TO 36G2-3-1, dated 15 March 1963, Change 17 dated 1 September 2007.

DISCLOSURE NOTICE - This information is furnished upon the condition that it will not be released to another nation without the specific authority of the Department of the Air Force of the United States, that it will be used for military purposes only, that individual or corporate rights originating in the information, whether patented or not, will be respected, that the recipient will report promptly to the United States, any known or suspected compromise, and that the information will be provided substantially the same degree of security afforded it by the Department of Defense of the United States. Also, regardless of any other markings on the document, it will not be downgraded or declassified without written approval of the originating United States agency.

DISTRIBUTION STATEMENT C - Distribution authorized to U.S. Government Agencies and their contractors (Administrative or Operational Use) (30 October 1996). Other requests for this document shall be referred to 406 SCMS/GUEE, Robins AFB, GA 31098. Questions concern-ing technical content shall be referred to AFLCMC/WNZEA.

WARNING - This document contains technical data whose export is restricted by the Arms Export Control Act (Title 22, U.S.C., Sec 2751, et seq.) or the Export Administration Act of 1979, as amended, Title 50, U.S.C., App. 2401, et seq. Violations of these export laws are subject to severe criminal penalties. Disseminate in accordance with provisions of DoD Directive 5230.25.

HANDLING AND DESTRUCTION NOTICE - Comply with distribution statement and destroy by any method that will prevent disclosure of contents or reconstruction of the document.

Published Under Authority of the Secretary of the Air Force

29 JUNE 2014

Dates of issue for original and changed pages are:

Original. . . . . . . .0 . . . . . . . 29 June 2014

TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 28, CONSISTING OF THE FOLLOWING:

Page *Change No. No.

Page *Change No. No.

Page *Change No. No.

Title A i - v vi Blank 1-1 - 1-4 2-1 - 2-8 3-1 - 3-7 3-8 Blank

TO 36G2-3-1

LIST OF EFFECTIVE PAGES

INSERT LATEST CHANGED PAGES. DESTROY SUPERSEDED PAGES.

NOTE The portion of the text affected by the changes is indicated by a vertical line in the outer margins of the page. Changes to illustrations are indicated by shaded or screened areas, or by miniature pointing hands.

* Zero in this column indicates an original page.

A USAF

TABLE OF CONTENTS

Chapter Page

LIST OF ILLUSTRATIONS . . . . . . . . . . . . . ii

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . ii

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . iii

SAFETY SUMMARY . . . . . . . . . . . . . . . . . v

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . 1-1

1.1 BASIC OPERATION . . . . . . . . . . 1-1

1.2 DESCRIPTION . . . . . . . . . . . . . . 1-3

1.2.1 General. . . . . . . . . . . . . . . . . . . . 1-3

1.2.2 Detail . . . . . . . . . . . . . . . . . . . . . 1-3

1.2.2.1 Blower . . . . . . . . . . . . . . . . . . . . 1-3

1.2.2.2 Motor . . . . . . . . . . . . . . . . . . . . . 1-3

1.2.2.3 Heater Assembly . . . . . . . . . . . . . 1-3

1.2.2.4 Filter . . . . . . . . . . . . . . . . . . . . . 1-3

1.2.2.5 Electrical Control Panel

Assembly . . . . . . . . . . . . . . . . 1-3

1.2.2.6 Heater Magnetic Contactor . . . . . . 1-3

1.2.2.7 Thermoswitch . . . . . . . . . . . . . . . 1-3

1.2.2.8 Overheat Thermostat. . . . . . . . . . . 1-3

1.2.2.9 Pressure Switch . . . . . . . . . . . . . . 1-4

1.2.2.10 Time Delay . . . . . . . . . . . . . . . . . 1-4

1.2.2.11 Servicing Hose and Adapters . . . . . 1-4

1.3 LEADING PARTICULARS . . . . . . 1-4

2 OPERATION AND SERVICE

INSTRUCTIONS . . . . . . . . . . . . . . . . . . 2-1

2.1 PREPARATION FOR USE . . . . . . 2-1

2.1.1 General. . . . . . . . . . . . . . . . . . . . 2-1

2.2 PRECAUTIONS TO BE

OBSERVED . . . . . . . . . . . . . . 2-1

2.3 DESCRIPTION OF OPERATING

CONTROLS . . . . . . . . . . . . . . 2-1

2.3.1 Hourmeter. . . . . . . . . . . . . . . . . . 2-1

2.3.2 Thermometer . . . . . . . . . . . . . . . . 2-2

2.3.3 48 Volt Power . . . . . . . . . . . . . . . 2-2

2.3.4 Motor Circuit Breaker. . . . . . . . . . 2-2

2.3.5 Motor Start-Stop . . . . . . . . . . . . . 2-2

2.3.6 Phase Reversal Switch . . . . . . . . . 2-2

2.3.7 Heater Circuit Breaker . . . . . . . . . 2-3

Chapter Page

2.3.8 Light Switch . . . . . . . . . . . . . . . . 2-3

2.4 OPERATION. . . . . . . . . . . . . . . . 2-3

2.4.1 Stopping the Unit . . . . . . . . . . . . . 2-3

2.5 PERIODIC LUBRICATION . . . . . 2-4

2.5.1 Wheel Bearings . . . . . . . . . . . . . . 2-4

2.5.2 Blower . . . . . . . . . . . . . . . . . . . . 2-4

2.5.3 Motor . . . . . . . . . . . . . . . . . . . . . 2-4

2.6 PERIODIC INSPECTION . . . . . . . 2-7

2.6.1 Prior to Use Inspection . . . . . . . . . 2-7

2.6.2 Troubleshooting . . . . . . . . . . . . . . 2-7

3 REPAIR INSTRUCTIONS. . . . . . . . . . . . . . 3-1

3.1 GENERAL . . . . . . . . . . . . . . . . . 3-1

3.2 DISASSEMBLY . . . . . . . . . . . . . 3-1

3.2.1 Purging Unit . . . . . . . . . . . . . . . . 3-1

3.2.2 Air Filter . . . . . . . . . . . . . . . . . . 3-1

3.2.3 Safety Relief Valve. . . . . . . . . . . . 3-1

3.2.4 Motor and Blower . . . . . . . . . . . . 3-1

3.2.5 Electrical Control Panel

Assembly . . . . . . . . . . . . . . . . 3-1

3.2.6 Body Assembly . . . . . . . . . . . . . . 3-1

3.2.7 Heater Assembly . . . . . . . . . . . . . 3-1

3.3 CLEANING . . . . . . . . . . . . . . . . 3-6

3.3.1 Piping . . . . . . . . . . . . . . . . . . . . 3-6

3.3.2 Motor . . . . . . . . . . . . . . . . . . . . . 3-6

3.3.3 Electrical System . . . . . . . . . . . . . 3-6

3.3.4 Heater Assembly . . . . . . . . . . . . . 3-6

3.3.5 Chassis and Body Assembly . . . . . 3-6

3.4 INSPECTION . . . . . . . . . . . . . . . 3-6

3.4.1 General. . . . . . . . . . . . . . . . . . . . 3-6

3.4.2 Wiring . . . . . . . . . . . . . . . . . . . . 3-6

3.4.3 Electrical Controls . . . . . . . . . . . . 3-6

3.4.4 Thermometers . . . . . . . . . . . . . . . 3-6

3.4.5 Drive Belts . . . . . . . . . . . . . . . . . 3-6

3.4.6 Air Filter . . . . . . . . . . . . . . . . . . 3-6

3.4.7 Servicing Hose Fittings . . . . . . . . . 3-6

3.4.8 Safety Relief Valve. . . . . . . . . . . . 3-6

3.4.9 Motor . . . . . . . . . . . . . . . . . . . . . 3-6

3.4.10 Repair and Replacement . . . . . . . . 3-6

3.4.11 Reassembly . . . . . . . . . . . . . . . . . 3-6

3.5 TEST AFTER REASSEMBLY . . . . 3-7

3.6 SPECIAL TOOLS . . . . . . . . . . . . 3-7

i

LIST OF ILLUSTRATIONS

Number PageTitle

1-1 Air Purging Unit, Type GSU-62/M . . . . . 1-2 1-2 Air Flow Schematic Diagram . . . . . . . . . 1-3 2-1 Operating Controls . . . . . . . . . . . . . . . . 2-2 2-2 Lubrication Diagram . . . . . . . . . . . . . . . 2-5

Number PageTitle

2-3 Electrical Schematic Diagram . . . . . . . . . 2-6 3-1 Air Purging Unit, Exploded View . . . . . . 3-2 3-2 Electrical Control Box. . . . . . . . . . . . . . 3-4 3-3 Air Filter, Exploded View . . . . . . . . . . . 3-5

LIST OF TABLES

Number PageTitle

1-1 Leading Particulars . . . . . . . . . . . . . . . . 1-4 2-1 Troubleshooting . . . . . . . . . . . . . . . . . . 2-7

Number PageTitle ii

FOREWORD

1 PURPOSE.

The Purging Unit is intended primarily for use in purging liquid-oxygen storage tanks and transfer tanks.

2 SCOPE.

This handbook contains operation, service and repair instruc-tions for an Air Purging Unit, Type GSU-62/M. (See Figure 1-1). The unit is manufactured by Randall Manufacturing Company, Hillside, New Jersey. It is identified by the manu-facturer as Model G-399 and Part Number (PN) 4000. The units were manufactured under Air Force Contract Number (No.) AF40(604)11856 and are identified by Federal Stock Number 3655-987-2586. This handbook should be used in conjunction with the Illustrated Parts Breakdown, Technical Order (TO) 36G2-3-4, covering this equipment.

3 SYMBOLS.

- A dash (-) before an index number denotes a part which is not illustrated.

* An asterisk (*) flush right of the part number denotes a marking that is to be requisitioned in accordance with DODI 5330.03_AFI 33- 395.

# A number sign (#) flush right of a part number indicates that detail parts are listed in a sepa-rate manual.

F The letter “F” before the figure number means “follows” and is used when an assembly or part has not been assigned an index number, and the figure and index number of the pre-ceding part has been used.

4 ABBREVIATIONS.

All abbreviations used in this manual are in accordance with ASME Y14.38, Abbreviations and Acronyms for Use on Drawings and Related Documents.

AF Air Force AFTO Air Force Technical Order ALT Alternate AMB Ambient AP Attaching Parts AR As Required ASSY Assembly

ATM Atmosphere CAGE Commercial and Government Entity CFE Contractor Furnished Equipment DoD Department of Defense Dis Displacement GFE Government Furnished Equipment HP Horse Power I&S Interchangeability and Substitution IN Inch IPB Illustrated Parts Breakdown KW Kilowatt Min Minimum MPL Maintenance Parts List NHA Next Higher Assembly NI Numerical Index NO. Number PM Pounds Per Minute PN Part Number PSI Pound Force Per Square Inch PSIG Pounds Per Square Inch Guage RDI Reference Designator Index REF Reference RPM Revolutions Per Minute SMR Source, Maintenance, and Recoverability SPEC Specification STD Standard TEMP Temperature TO Technical Order UOC Usable on Code V Volt

5 RELATED PUBLICATIONS.

The following publications contain information in support of this technical manual.

List of Related Publications

Number Title ASME Y14.38 Abbreviations and Acronyms for Use on Drawings and Related Documents

DODI 5330.03_AFI 33-395 Document Automation and Production Service

(DAPS)

iii

List of Related Publications - Continued

Number Title TO 00-5-1-WA-1 Air Force Technical Order

System TO 00-25-195-WA-1 Source, Maintenance, and

Recoverability Coding of Air Force Weapons, Sys-tems, and Equipment

TO 00-25-234-WA-1 General Shop Practice Re-quirements for the Repair, Maintenance, and Test of Electrical Equipment

List of Related Publications - Continued

Number Title TO 36G2-3-4 Illustrated Parts Breakdown

Air Purging Unit Type

GSU-62/M PN 4000 NSN

3655-00-987-2586

6 RECORD OF APPLICABLE TIME COMPLIANCE

TECHNICAL ORDERS (TCTOS).

List of Time Compliance Technical Orders

TCTO

Number

TCTO

Title

TCTO

Date

None

7 HARDNESS CRITICAL ITEMS (HCI).

The HCI symbol ( ) establishes special re-quirements limiting changes and substitutions and that the specific parts listed must be used to ensure hardness is not degraded.

If included, items with nuclear survivability requirements are marked with the HCI symbol ( ). All changes to, or pro-posed substitutions of, HCIs must be approved by the ac-quiring activity.

8 ELECTROSTATIC DISCHARGE SENSITIVE

(ESDS) ITEMS.

All ESDS parts shall be handled in accordance with the ESDS device handling procedures in TO

00-25-234-WA-1.

If included, items containing ESDS parts are marked with the ESDS symbol ( ).

9 CHANGE RECOMMENDATIONS.

Recommendations proposing changes to this technical order shall be submitted on an AFTO Form 22 in accordance with TO 00-5-1-WA-1. Forward completed AFTO Form 22 to the Technical Order Management Agency (TOMA) at:

robins.ce.afto22@us.af.mil.

iv

SAFETY SUMMARY

1 GENERAL SAFETY INSTRUCTIONS.

This manual describes physical and/or chemical processes which may cause injury or death to personnel, or damage to equipment, if not properly followed. This safety summary includes general safety precautions and instructions that must be understood and applied during operation and maintenance to ensure personnel safety and protection of equipment. Prior to performing any specific task, the WARNINGs, CAU- TIONs, and NOTEs included in that task shall be reviewed and understood.

2 WARNINGS, CAUTIONS, AND NOTES.

WARNINGs and CAUTIONs are used in this manual to highlight operating or maintenance procedures, practices, conditions, or statements which are considered essential to protection of personnel (WARNING) or equipment (CAU- TION). WARNINGs and CAUTIONs immediately precede the step or procedure to which they apply. WARNINGs and CAUTIONs consist of four parts: heading (WARNING, CAUTION, or icon), a statement of the hazard, minimum precautions, and possible results if disregarded. NOTEs are used in this manual to highlight operating or maintenance procedures, practices, conditions, or statements which are not essential to protection of personnel or equipment. NOTEs may precede or follow the step or procedure, depending upon the information to be highlighted. The headings used and their definitions are as follows:

Highlights an essential operating or maintenance procedure, practice, condition, statement, etc., which if not strictly observed, could result in in-jury to, or death of, personnel or long term health hazards.

Highlights an essential operating or maintenance procedure, practice, condition, statement, etc., which if not strictly observed, could result in dam-age to, or destruction of, equipment or loss of mis-sion effectiveness.

NOTE

Highlights an essential operating or maintenance procedure, condition, or statement.

v/(vi blank)

CHAPTER 1

INTRODUCTION

1.1 BASIC OPERATION.

The Purging Unit accomplishes its intended function as fol-lows: (See Figure 1-2). A blower, driven by an a-c motor, draws air into the unit piping via a cleanable element air filter. The air is then delivered to a heater assembly where the air is heated to 350 °F - 375 °F. The heated air is then discharged through a hose assembly to the liquid-oxygen storage tank to be purged. The temperature to which the air is to be heated is thermostatically controlled; the heater out-put air temperature is measured by a dial thermometer; a pressure relief valve in the heater inlet piping prevents ex-cessive pressure build-up; and a pressure switch combined with a time delay cutout relay prevents equipment damage due to lack of, or reversed air flow. The operation of the unit is controlled from an electrical control panel which also con-tains the electrical control components. An accessory device is also furnished with the unit which consists of a dial ther-mometer affixed to a clamp. This device is clamped to output of the liquid-oxygen storage tank and will indicate the purged air temperature.

1-1

Figure 1-1. Air Purging Unit, Type GSU-62/M

1-2

1.2 DESCRIPTION.

(See Figure 3-1).

1.2.1 General. The unit consists essentially of a motor

(30), blower (33), electrical control panel assembly (88), and heater assembly (52), all of which are mounted to the bed of the trailer. The motor drives the blower via a dual belt-pulley arrangement and the air filter (25) is connected directly to the blower. System piping for air flow interconnects the blower and heater assembly, and heater assembly and servic-ing hose. The components of the trailer are completely en-closed by a shroud (11). The shroud has four top-hinged panels (12) on the sides which can be locked in either the down position (during storage or non-operation) or up (dur-ing operation). The rear of the shroud has a heater access panel (13) to facilitate removal of the heater elements (61) when required. Also on the rear of the shroud is a bracket (3) designed for storage of the electrical power cable (2). The trailer chassis (92), upon which all these components rest, is of welded channel construction and is supported by a four-wheel running gear and braking mechanism (89). The run-ning gear is of the unsprung type, the two front wheels being steerable by means of a towbar and the two rear wheels being fixed. A built-in brake in the rear wheels is controlled by a hand lever on the right side of the trailer. The braking mechanism is for parking purposes only. Mounted directly on the chassis frame is a rear pintle hook (6) which permits tandem towing of other vehicles, tie-down rings for securing the trailer during transportation and reflectors (4 and 5) for road safety.

1.2.2 Detail. The following major components are further

described because of their importance in the understanding and operation of the unit.

1.2.2.1 Blower. The blower is a rotary positive displace-

ment unit which utilizes a 3-lobe rotor design. It is capable of delivering oil-free air to the heater assembly at a rate of 6 Pounds Per Minute (PM) under environmental conditions given in Paragraph 1.2.2.7. Blower end plates are drilled to allow free flow of lubrication between bearings and seals without contaminating the air being delivered.

1.2.2.2 Motor. The motor is a 5 Horse Power (HP), 3

phase, 60 cycle, 2 pole unit that rotates at 3600 Revolutions Per Minute (RPM). The motor can be operated from either a 220 or 440 volt, 3 phase, 60 cycle power source.

1.2.2.3 Heater Assembly. The heater assembly consists

of six electrical heating elements mounted in an insulated cylindrical chamber. The purpose of the heater assembly is to heat the incoming air from the blower. The heater is ther-mostatically controlled to insure maintaining the outlet tem-perature of the purging unit at 350 °F ±10 °F throughout the complete purging operation. The heater assembly has an over-all efficiency of power transfer from the heating coils to the purging air of approximately 85%. The unit is designed so that the heating elements are readily accessible for re-moval, and periodic maintenance.

1.2.2.4 Filter. The air intake opening of the blower is pro-

tected by a permanent type washable filter capable of arrest-ing all particles 40 microns or larger.

1.2.2.5 Electrical Control Panel Assembly. This com-

posite instrument and control panel enables the operator to operate the equipment. Mounted within the electrical box are the circuit breakers, thermostat, transformer, etc. Illumina-tion of the control panel is provided by a manually operated white light.

1.2.2.6 Heater Magnetic Contactor. The heater magnetic

contactor (Figure 3-2, 14) receives power via the heater cir-cuit breaker and is controlled by a thermoswitch (Figure 3-1,

82) located in the heater outlet line. The magnetic contactor cycles automatically at least once every minute and will in-terrupt power to the heater if the temperature exceeds 350 °F. The holding coil of the contactor operates from the 110 volt branch of the circuit and a capacitor (Figure 3-1, 81) wired in parallel with the contactor prevents excessive con-tactor chatter.

1.2.2.7 Thermoswitch. This switch (82) is factory ad-

justed at 350 °F but can be easily readjusted in the field by removing the cover from junction box (83), disconnecting capacitor (81) and inserting a screwdriver into the slotted head of the thermoswitch. Rotate thermoswitch adjustment counter-clockwise to increase temperature setting and clock-wise to decrease temperature setting. Do not attempt to change the temperature more than a few degrees at a time.

Replace the capacitor when the setting is completed.

1.2.2.8 Overheat Thermostat. The overheat thermostat

(Figure 3-2, 25) is a protective device located inside the con-trol panel but its sensing bulb is located in the heater cham-ber via a capillary tube. The overheat thermostat is factory set at 400 °F and can be easily adjusted by rotating the con-trol knob (23). If this thermostat opens the entire 110 volt control power will be disconnected, thus preventing blower or heater operation.

Figure 1-2. Air Flow Schematic Diagram

1-3

1.2.2.9 Pressure Switch.

The thermostat will not control if the capillary tube is pinched or broken.

The pressure switch (Figure 3-2, 27) is activated by air via a 1/4 inch (in.) copper line connected to the blower outlet. Its purpose is to check for positive air pressure, thereby provid-ing positive indication of blower operation. For continued operation of the blower the switch must remain closed.

1.2.2.10 Time Delay. The time delay relay (Figure 3-2,

21) is a thermal type relay that is connected in the motor starter circuit and provides the initial method of starting the motor. However, 45 seconds after the motor is started the relay will open but motor operation will continue by virtue of the pressure switch maintaining electrical continuity.

1.2.2.11 Servicing Hose and Adapters. The servicing

hose is 10 feet long and is covered by a scuff resistant jacket.

The inside diameter of the hose is 1-1/4 inch. The free end of the hose contains a quick disconnect coupling which fits any of the three adapters employed. The three adapters are 1inch ips, 1-1/2 inch ips, and 2 inch ips (Figure 3-1, 22, 23, 24 respectively) and are furnished with the unit. The special adapters are provided for attachment of the servicing hose to the vent line of the lox tank to be purged.

1.3 LEADING PARTICULARS.

The following lists the leading particulars of the trailer:

Table 1-1. Leading Particulars

Item Description Overall Length 86 inches Overall Height 52 inches Overall Width 55 inches Net Weight (Shipping) 1500 pounds Servicing Hose Length 10 feet Power Cable Length 50 feet Flow Rate (-65 °F and Standard (STD) Atmosphere (ATM)

Pressure (PRESS)) Minimum (Min) 6 Pounds Per Minute (PM) with Displace-ment (Dis) PRESS. not less than 5 Pounds Per Square Inch Gauge (PSIG)

Outlet Temp. of Purging Air Ambient (AMB) Temperature (TEMP) range -65 to +130 °F

350 °F ±10 °F

Environmental Capabilities:

Operation AMB TEMP -65 to +130 °F Storage AMB TEMP -80 to +160 °F Relative Humidity 95% at 130 °F Rainfall Any locale Salt Spray Coastal areas Sand and Dust Desert areas Fungus Tropical and subtropical areas Tire Type Pneumatic Tire Size 6:00 x 9 Tire pressure See Paragraph 2.1.1 (i) Unit Power Requirements 220 Volt(V)/440V, 3 phase, 60 cycle Motor Characteristics 5 hp 440V/7.5A 220V/15A Heater Characteristics 12 Kilowatt (KW) 440V/16A 220V/32A Equipment Specification (SPEC) MIL-P-27456A

1-4

CHAPTER 2

OPERATION AND SERVICE INSTRUCTIONS

2.1 PREPARATION FOR USE.

2.1.1 General. The unit is shipped completely assembled.

To prepare for use, dismount the unit from the shipping ve-hicle and remove all tape, paper, wrappings, etc. from the unit and components, and perform the following.

a. Check that the safety relief valve (Figure 3-1, 45) is lockwired.

b. Check all mounting and piping joints to determine that they are secure. Tighten where necessary.

c. Check to see that all accessories (three adapters (22, 23 and 24) and thermometer-clamp assembly (21) are present and in good physical condition.

d. Check all lubrication points referred to in Figure 2-2 and Paragraph 2.5. Be sure initial lubrication exists at all specified points.

e. Check belt tension. It should not be too loose or too tight. The belt tension can be adjusted by referring to Paragraph 2.6.1 Step c.

f. Check that the glass covered instruments (hourmeter and thermometer) and light bulbs are not cracked or damaged.

g. Check electrical connections for tightness.

h. Check control panel switches for ease of operation and freedom from binding.

i. Check and maintain tire pressure as specified on side-wall of tire or pressures may be obtained by ordering the Tire and Rim Association Yearbook or at discretion of using activity.

NOTE

Used aircraft tires may be employed as alternates for the specified tires of proper size.

j. The unit as shipped from the factory is wired for 440 volts. If the electrical power source available for op-eration of the unit is 220 volts, the unit must be slightly rewired as shown in Figure 2-3 or the voltage conver-sion plate on the unit.

2.2 PRECAUTIONS TO BE OBSERVED.

a. When unit is not in use close and latch all access doors.

b. Keep the parking brake engaged at all times when the trailer is in use or is uncoupled from a towing vehicle.

c. Raise the towbar to a vertical position when not in use.

It will lock in this position. To lower the towbar the locking device must be released.

d. Coil the servicing hose and power cable neatly when not in use and stow properly.

e. Blower rotation should always be in the direction of the arrow.

f. If the heater or motor circuit breakers trip repeatedly, shut the unit down and determine the cause of the overload before resuming operation. See Paragraph 2.6.2, Troubleshooting.

g. Before starting up the unit check that all switches and controls are in the off position.

h. If the safety relief valve pops off, shut the unit down and determine and remedy the cause of the excessive pressure or faulty valve before resuming operation.

i. Disconnect electrical power unless required for trouble-shooting.

2.3 DESCRIPTION OF OPERATING CONTROLS.

This unit when in operation contains voltage which is dangerous to life. Always shut the unit down before opening the electrical control box. Be care-ful not to come into contact with power connec-tions when using this equipment.

The majority of controls required for operation of this unit are located on the electrical box control panel. (See Figure 2-1). The function of each control is described in this para-graph.

2.3.1 Hourmeter. The hourmeter is a time totalizer which

indicates the number of hours the equipment has been in operation. It serves as a convenient guide in determining when inspection and maintenance procedures are to be per-formed, particularly when to change the oil in the blower, Paragraph 2.5.2. The hourmeter will be energized whenever the motor is operating.

2-1

2.3.2 Thermometer. There are two dial thermometers

used in this equipment. One is located on the output line of the heater and indicates the outlet temperature of the air leaving the heater. The other thermometer is affixed to a clamping device that is easily adaptable to the liquid-oxygen tank outlet. This thermometer will read the outlet tempera-ture of the system being purged. The thermometer gauges are calibrated from 50° to 550 °F.

2.3.3 48 Volt Power. This double pole single throw switch controls power to the Air Force Grid system. When ON the unit can be energized and when OFF the unit cannot be en-ergized. In the ON position the associated red pilot light will illuminate indicating that power should be available at the trailer.

2.3.4 Motor Circuit Breaker. This circuit breaker controls

energizing power to the motor and thus permits the motor to be started by means of the motor start-stop switch. In the event of overload the circuit breaker will trip to the OFF position, thus stopping the motor. After waiting a few min-utes, the circuit breaker can be reset by pushing down the ON lever.

2.3.5 Motor Start-Stop. This push-button switch controls

the motor by means of a magnetic motor starter with a 110 Volt (V) starting coil. However, the motor circuit breaker must be ON (Step d) before this switch can assume control.

Press the green button to start the motor and the red button to stop the motor. In the event of excessive motor load the thermal overloads of the starter will stop the motor. These overloads will automatically reset in 1 to 3 minutes. The blower should run 5 minutes before attempting to close the heater circuit breaker (Step g).

2.3.6 Phase Reversal Switch. The phase reversal switch

is located on the left end of the control panel. The purpose of this switch is to prevent damage to the blower by driving it in the wrong direction (against the arrow). It facilitates changing the direction of rotation of the motor. Always wait for the blower to come to a dead stop before attempting to reverse its rotation.

Figure 2-1. Operating Controls

2-2

2.3.7 Heater Circuit Breaker. This circuit breaker con-

trols energizing power directly to the six heater elements of the unit. In the event of heater overload this circuit breaker will trip and remove power from the heaters. After 1-3 min-utes the circuit breaker can be reset by pushing down the ON lever.

2.3.8 Light Switch. The light switch controls the panel

light; however, the 48 volt power switch (Step c) and the motor circuit breaker (Step d) must be on for this switch to be effective. The panel light furnishes illumination for the control panel and adjacent areas.

2.4 OPERATION.

Instructions contained herein are for the operation of the purging unit. For proper purging procedures and pertinent warnings, reference applicable Tech-nical Order of equipment to be purged.

a. Tow the trailer within 10 feet of the liquid oxygen tank to be purged and within 50 feet of the proper electrical power source. Do not stretch the hose or cable to make a connection - move the trailer.

b. Apply the parking brake.

c. Screw either the 1-inch, 1-1/2-inch or 2-inch adapter into the vent line of the liquid-oxygen tank, whichever adapter is applicable.

d. Secure the air thermometer-clamp assembly to the out-let of the liquid-oxygen tank in order to monitor the outlet temperature of the tank being purged.

e. Check that all switch and circuit breakers are off and connect the electrical power cable into the power source.

f. Place the 48 volt power switch ON. The associated red pilot light should light when an Air Force Grid system is employed.

g. Close the motor circuit breaker and push the green button of the motor start-stop switch.

• Check that the blower is rotating in the proper direction - with the arrow.

• If rotation is opposite the arrow, push the red button of the motor start-stop switch. When the motor comes to rest, place the phase reversal switch to its opposite position and once again start the motor by pushing the green button of the motor start-stop switch.

NOTE

The unit will automatically shut down after 45 seconds if blower rotation is wrong. However, it is best to get the rotation correct before the auto-matic safety features take over.

h. Close the heater circuit breaker five minutes after it is determined that the blower is rotating properly. In ap-proximately 10 minutes the thermometer on the heater outlet should read 350 °F.

i. When proper purging temperature is reached, connect the servicing hose quick disconnect to the adapter on the liquid-oxygen tank and snap the quick disconnect closed.

j. Purge the liquid-oxygen tank while monitoring the outlet temperature. Purging is complete when outlet temperature as registered on the air thermometer clamp assembly reaches 220 °F.

k. Stop the unit, Paragraph 2.4.1.

2.4.1 Stopping the Unit. (See Figure 2-1).

a. Switch the heater circuit breaker to OFF. Wait five minutes for the heater to cool.

b. Push the red button of the motor start-stop switch.

c. Switch the motor circuit breaker to OFF.

d. Turn the 46 volt power switch to the OFF position.

e. Turn the panel light switch off.

f. Disconnect the servicing hose from the adapter by opening up the quick disconnect. Coil and store the servicing hose neatly within the enclosure.

g. Disconnect the electrical power cable from the power source and coil the cable neatly about the bracket on the rear of the enclosure. It can remain permanently connected if the trailer is not to be moved.

h. Unscrew the adapter from the liquid-oxygen tank and store within the unit. It can be permanently attached unless required for other tanks.

i. Close and latch down the access doors.

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j. Log the number of hours the unit has been run as in-dicated on the hourmeter.

2.5 PERIODIC LUBRICATION.

Figure 2-2 gives the general lubrication information for the unit. However, more detailed information is necessary for certain components as follows.

2.5.1 Wheel Bearings.

a. Remove the hub cap, cotter pin and castellated nut from each wheel.

b. Pull the wheel off the tie and grease the radial bearing with MIL-G-10924. Exercise care to prevent grease from getting on the brake lining of the rear wheels.

c. Replace the bearing and tighten wheel to axle. Replace hub cap.

2.5.2 Blower.

NOTE

The disappearance of oil from the sight gauge dur-ing operation is normal. The oil level should only be checked when the blower is in a static condi-tion.

a. Under normal conditions oil level on each end of the blower should be checked every 25 hours of operation.

Change oil every 180 days. Under extremely hot or dusty condition, oil level should be checked oftener and may require frequent changes. After oil has been drained from each end of the blower, refill each end with approximately 11-oz of oil or until sight glass is 3/4 full.

b. Every 180 days the oil sump breather should be re-moved, cleaned in solvent and blown out with clean compressed air, to provide unobstructed venting of the gear case and free end of blower.

NOTE

Use the following lubricants for the blower only:

Detergent Oils: MIL-L-2104A

Other Oils: Mobil Special 10W-30, Socony Vacuum Oil Co.

Recommended Weights - Below 50 °F SAE 20 Above 50 °F SAE 30

Inspect the magnetic plug for iron particles at the same time.

c. Run the blower for two hours after lubrication with the heat on. This will assure that oil-free air will be deliv-ered when the unit is placed in operation.

2.5.3 Motor. Every 180 days lubricate the motor as fol-

lows:

a. Wipe the area surrounding the lubrication plugs. Re-move the filler plugs.

b. With motor shut down fill the cavity with oil (not heavier than SAE 10).

c. Turn the motor over by hand for several minutes.

d. Open the drain plug and rotate the shaft by hand while the oil drains.

e. Insert a standard Y8 in MPT Zerk fitting.

f. Refill the bearing cavity with grease MIL-L-15719 and run motor for approximately 20 minutes before replac-ing drain plug to allow excess grease to flow out.

Grease reservoir not to be more than 2/3 full.

g. Remove the MPT Zerk fitting and reinstall filler plugs.

NOTE

High humidity and high temperature conditions require more frequent lubrication.

2-4

Figure 2-2. Lubrication Diagram

2-5

Figure 2-3. Electrical Schematic Diagram

2-6

2.6 PERIODIC INSPECTION.

NOTE

Inspection interval will be every 180 days as de-termined by the Command/Chief of Maintenance.

2.6.1 Prior to Use Inspection.

Use approved personal protective equipment (goggles/face shield) when using compressed air.

Maximum allowable air pressure for cleaning op-erations is restricted to less than 30 PSI Provide protection from frying particles when using com-pressed air. Do not direct airstream towards self or other personnel.

a. Remove and check air filter element (Figure 3-3, 8). If it is clogged or dirty, it may be cleaned by light rap-ping or washing in water with a mild household deter-gent. Blow dry after cleaning.

b. Check the daily lubrication points. See Paragraph 2.5.

c. Check belt tension. If belt tension is too tight, loosen the motor mounting hardware and move the motor for-ward until belt tension eases up sufficiently. If belt ten-sion is too loose, slide the motor backwards until belt tension tightens sufficiently. After the belt tension is adjusted, tighten the motor base.

d. Clean and blow dry with oil-free air the three adapters and the quick disconnect on the end of the servicing hose.

Grease or oil must be kept away from parts which come into contact with liquid-oxygen.

e. Check all plumbing connections and hose clamps, making sure that they are tight and are not showing any evidence of strain.

f. Check all mounting hardware and fittings for tightness.

g. Check all electrical connections and make sure the electrical control box panel is screwed closed tightly.

When closing the electrical control panel, be cer-tain that the levers on the circuit breaker covers (Figure 3-2, 5) mate properly with the circuit breaker plastic switch handles (Figure 3-2, 17).

h. Check servicing hose for wear or deterioration.

i. Check cables for wear or deterioration.

2.6.2 Troubleshooting. Table 2-1 under Trouble, Probable

Cause and Remedy columns outlines possible difficulties which may be encountered in the operation of the equipment and means of remedying these possible malfunctions.

Table 2-1. Troubleshooting

Trouble Probable Cause Remedy MOTOR WILL NOT START 46 volt power switch OFF or defective. Place switch ON or replace if defective.

Motor circuit breaker open or defec-tive.

Close motor circuit breaker or replace if defective.

Time delay circuit open. Check wiring.

Defective time delay. Replace.

Motor start-stop switch OFF or defec-tive.

Push green button of switch or replace if defective.

Motor starter coil defective. Replace motor starter.

High limit switch defective (open). Replace.

Cartridge fuse blown in control trans-former.

Replace fuse.

Control transformer defective. Replace.

Overloads burnt out. Replace.

Motor defective. Replace motor.

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Table 2-1. Troubleshooting - Continued

Trouble Probable Cause Remedy

UNIT SHUTS DOWN 45 SEC-

ONDS AFTER MOTOR IS

TURNED ON

Blower rotating in wrong direction. Reverse motor rotation by means of phase reversal switch.

Plugged copper line, to pressure switch.

Blow out or tighten line.

Leak in copper line to switch. Tighten.

Pressure switch defective. Replace pressure switch.

Pressure switch set too high. Readjust. Turn adjustment screw clock-wise to lower actuation point.

Blower defective. Replace or repair blower.

Air filter completely clogged. Clean or replace filter element.

EXCESSIVE AIR OUTLET TEM-

PERATURE INDICATED ON

THERMOMETER

Thermometer defective. Replace thermometer.

Thermoswitch set too high. Readjust.

Thermoswitch defective. Replace.

AIR OUTLET TEMPERATURE

TOO LOW

One or more heater elements defective. Replace heater element(s).

Low voltage. Check for proper power source.

Thermoswitch set too low. Readjust.

Thermoswitch defective. Replace.

Magnetic contactor poles open. Clean points or replace.

Magnetic coil open. Replace contactor.

Heater circuit breaker open or defec-tive.

Close heater circuit breaker or replace if defective.

SAFETY RELIEF VALVE POPS Excessive pressure build-up. Check air flow lines.

Defective safety relief valve. Replace valve.

UNIT STOPS DURING OPERA-

TION

Loss of power. Restore power.

RUNNING GEAR ACTING IM-

PROPERLY WHILE TRAILER IS

BEING TOWED

Hand brake is on. Release hand brake.

Running parts worn or defective. Repair or replace running gear parts Lu-bricate (See Figure 2-2).

2-8

CHAPTER 3

REPAIR INSTRUCTIONS

3.1 GENERAL.

The trailer can be disassembled into its major component parts by referring to Figure 3-1 and Figure 3-2. However, complete disassembly is seldom, if ever, required and the nature of the equipment precludes complete overhaul, in-spection and repair. Therefore, remove only those parts for cleaning, inspection and repair that show signs of wear or known to be malfunctioning (refer to Troubleshooting).

Needless removal of parts increases the chances of breakage.

Whenever possible components should be inspected and cleaned without removal from the trailer.

3.2 DISASSEMBLY.

3.2.1 Purging Unit. The Purging Unit can be disassembled

into major components and parts by referring to the diagram and index of Figure 3-1. The following precautions should be observed, however, during disassembly.

a. Disconnect cable assemblies before removing any elec-trical components such as the motor (30), heater as-sembly (52) and electrical control panel assembly (88).

b. Do not bend the pressure switch tube assembly unnec-essarily. Repeated bending can cause it to work-harden and break.

c. Keep all disassembled parts away from oil, grease or other readily oxidizable materials.

3.2.2 Air Filter.

Use approved personal protective equipment (goggles/face shield) when using compressed air.

Maximum allowable air pressure for cleaning op-erations is restricted to less than 30 Pound Force

Per Square Inch (PSI) Provide protection from flying particles when using compressed air. Do not direct airstream towards self or other personnel.

The air filter can be easily disassembled by referring to Fig-ure 3-3. Check the filter element and clean by light rapping or washing in water with a household detergent. Wipe and blow dry after cleaning.

3.2.3 Safety Relief Valve. The safety relief valve (Figure

3-1, 45) should not require repair or servicing during the life of the equipment. If the valve is found to be malfunctioning, replace the entire valve.

3.2.4 Motor and Blower. The explosion proof motor (Fig-

ure 3-1, 30) and blower (33) are precision manufactured components and should be forwarded to depot for overhaul if beyond field capability to repair.

3.2.5 Electrical Control Panel Assembly. The electrical

control panel assembly can be disassembled into its compo-nent parts by referring to the diagram and index of Figure 3-2.

NOTE

Tag each lead before it is removed and remove only those leads necessary to accomplish disas-sembly.

3.2.6 Body Assembly. The doors, latches, handles, etc.

can be removed from the body assembly (11) by referring to Figure 3-1.

3.2.7 Heater Assembly. The heater assembly (52) can be

completely disassembled into its component parts by refer-ring to Figure 3-1. However, the heater coils can be removed from the trailer via the heater access door on the rear of the body assembly without undue assembly.

3-1

Figure 3-1. Air Purging Unit, Exploded View (Sheet 1 of 2)

3-2

Figure 3-1. Air Purging Unit, Exploded View (Sheet 2)

3-3

Figure 3-2. Electrical Control Box

3-4

Figure 3-3. Air Filter, Exploded View

3-5

3.3 CLEANING.

• Mineral Spirits are flammable and moderately toxic to shin, eyes and respiratory tract. Shin and eye protection is required. Good general ventilation is normally adequate.

• Trichloroethane (Methyl Chloroform) is mod-erately toxic to skin, eyes and respiratory tract.

Skin, eye and respiratory protection is required.

• Use approved personal protective equipment (goggles/face shield) when using compressed air. Maximum allowable air pressure for clean-ing operations is restricted to less than 30 PSI Provide protection from flying particles when using compressed air. Do not direct airstream towards self or other personnel.

3.3.1 Piping. Remove dirt and foreign matter. Wipe with a

clean, lint free cloth and blow dry.

3.3.2 Motor. Wipe clean or vacuum provided a suction

nozzle is used that is non-magnetic. Mineral spirits may be used to clean off gummy grease and dirt deposits. Inflam-mable fluids should never be used.

3.3.3 Electrical System. Using a small brush remove all

dirt from switches, connectors and other contacts. Wipe the contacts with a lint free cloth moistened in isopropyl alco-hol, TT-I-735. Burnish all terminals and contacts with fine sandpaper. Remove all line deposits from the bulb of ther-mostat switches with fine sandpaper. Wipe off the switches with a cloth dampened in isopropyl alcohol, TT-I-735.

3.3.4 Heater Assembly. Inspect metal shell for cracks or

other obvious physical defects. Make sure that the insulation is intact all around the shell. Scrape off any deposits on the heating elements and wipe dry.

3.3.5 Chassis and Body Assembly.

Conduct all painting operations in an approved spray booth/area equipped with adequate ventila-tion and exhaust.

Using a wire brush remove all corrosion and accumulated dirt from the exterior surfaces. Coat all paint free surfaces with Primer TT-P-664 and then paint with yellow enamel

TT-E-489.

3.4 INSPECTION.

3.4.1 General. Inspect all pipe fittings for bent, stripped

or deteriorated condition. Inspect all sheet metal parts for dents and cracks which would impair proper alignment with adjacent parts. Inspect all hardware and other threaded or tapped pieces for stripped or otherwise damaged threads.

3.4.2 Wiring. Inspect all wiring for security of insulation.

Remove and discard wires which show indication of having burned or deteriorated insulation.

3.4.3 Electrical Controls. Inspect contacts for burned or

pitted condition. Use a test lamp to check switches for con-tinuity of circuit.

3.4.4 Thermometers. Check the thermometer accuracy

against standard test equipment.

3.4.5 Drive Belts. Check drive belts for distortion, tears

or signs of incipient failure.

3.4.6 Air Filter. Check cleanliness of air filter element.

3.4.7 Servicing Hose Fittings. Check fittings for freedom

from dirt, oil or grease.

3.4.8 Safety Relief Valve. Check that the lever on the

safety relief valve is lock-wired.

3.4.9 Motor. The motor should be given a visual inspec-

tion for charred or cracked wires and an Revolutions Per Minute (RPM) check under no load. The motor should run at approximately 3600 RPM If either visual or RPM inspection is unsatisfactory replace the motor.

3.4.10 Repair and Replacement. Repair of components

of this equipment should be attempted only when such pro-cedure will restore the part to original condition without im-pairing operation. For this reason care should be exercised in determining whether or not the component should be repaired or replaced. If in doubt, replace the component.

3.4.11 Reassembly. Reassembly is essentially the reverse

of disassembly and can be accomplished by referring to Fig-ure 3-1 and Figure 3-2 while observing the following:

a. When installing electrical components constantly refer to the diagram of Figure 2-3 in order to assure proper wiring connections.

b. Check belt tension between the motor and blower.

Loose belts will slip and the blower will operate at a low speed, with consequent loss of air flow and over-

3-6 heating. If belts are too tight, drive shaft bearing will be overloaded. Move the motor in its base (forward or backward) to obtain proper belt tension.

c. Pipe thread sealing material (MIL-T-5542 or equiva-lent) shall be applied to all pipe threaded fittings.

3.5 TEST AFTER REASSEMBLY.

Conduct an operational test of the equipment after reassem-bly, as outlined in Paragraph 2.4, without connecting the ser-vicing hose to a liquid-oxygen tank. If the unit operates properly, it can then be returned to service.

3.6 SPECIAL TOOLS.

No special tools are required for the maintenance of this equipment.

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