2.3.1 Student Book © 2004 Propane Education & Research CouncilPage 1 2.3.1 Identifying Equipment & Procedures Used on Propane Transports Most of the propane

2.3.1 Student Book © 2004 Propane Education & Research Council Page 1

2.3.1

Identifying Equipment & Procedures Used on Propane

Transports

Most of the propane used by residential, commercial and industrial customers is transported to bulk plants or directly to large customer accounts by tractor-trailer transports.

In this module, you will learn to:

(1) Identify applications and features of propane transports

(2) Maintain and operate pumps and associated circuits on transports

(3) Identify functions of emergency discharge control systems and safety features of transports

(4) Identify U.S. DOT cargo tank labeling and markings


Features of Propane Transports

In U.S. Department of Transportation regulations in some cases use the term “transport” to refer to any bulk cargo tank motor vehicle, regardless of its size or configuration. DOT regulations also call bulk delivery vehicles cargo tank motor vehicles (CTMVs). In the propane industry, transports are understood to mean tractor/trailer combination vehicles that have semi-trailers that are cargo tanks.

“Metered delivery service” means an unloading operation conducted at a metered flow rate of 100 gallons per minute or less through an attached delivery hose with a nominal inside diameter of 1.25 inches or less. The majority of propane transports are not equipped with liquid meters and small diameter delivery hoses, and are not used in metered delivery service.



Regardless of their size, application, or devices used to control their operation, all transports have basic features and equipment in common.

Figure 1. Cargo Tank Motor Vehicle



Cargo Tank

Figure 2. Typical Features of Transport Cargo Tanks



Data Plate

Figure 3. Cargo Tank Data Plates

Name Plate

Specification Plate

May be combined in a single data plate.



Data Plate

Figure 4. MC 331 Cargo Tank Data Plate



Cargo tanks have the following openings for connections:

• Liquid level gauges

• Temperature well

• Pressure gauge

• Cargo tank fill and equalizing connections

• Cargo tank withdrawal connection

• Pressure relief valve(s)



Rotary Gauge

Figure 5a. Rotary Gauge



Rotary Gauge

Figure 5b. Cross Sectional View of Rotary Gauge



Rotary Gauge

Figure 6. Rotary Gauge Face



Float Gauge

Figure 7a. Float Gauge

Figure 7b. Cargo Tank 50% Liquid Filled



Fixed Liquid Level Gauges

Figure 8a. Fixed Liquid Level Gauge Outage

Figure 8b. Cross Sectional View in Cargo Tank

Fixed M axim umLiquid LevelGauges

Liquid Propane

80%

85%



Thermometer & Pressure Gauge

One method of checking the accuracy of rotary and float gauges is to fill the cargo tank with propane until a white mist vents out of the fixed maximum liquid level gauge. The rotary and float gauges should indicate the same percentage of tank volume as indicated by the fixed maximum liquid level gauge if you have a liquid temperature near 40° F.

Fixed maximum liquid level gauges installed in pressure cargo tanks are used each time the tank is filled. The pressure gauge and thermometer are used to check the load of gas in the cargo tank, while the thermometer and scales on the liquid level gauge are used to determine the maximum permitted filling level.



Fixed Liquid Level Gauges

Figure 9. Fixed Maximum Liquid Level Gauge



Temperature Well & Thermometer

Figure 10. Temperature Well

Figure 11. Dial Indicating Temperature Gauge



Temperature Well & Thermometer

Figure 12. Thermometer, Pressure GaugeAnd Fixed Liquid Level Gauges



Loading, Unloading and Vapor Equalizing Connections

The fill and equalizing connections in propane cargo tanks vary according to their applications for metered or un-metered delivery service. The vapor equalizing connections always contain a riser inside the tank that extends to the vapor space in the cargo tank. The fill connection in most cargo tanks connects to a riser used to "spray fill" the tank.

When piping is installed, even though the fill connection and the connected bypass piping will contain liquid propane, the opening at the outside of the cargo tank must be permanently labeled either “VAPOR” or “Spray-Fill” because the piping ultimately communicates with the vapor space of the cargo tank due to the spray fill feature.




Figure 13. Schematic Drawing of Transport Cargo TankLoading, Unloading and Vapor Equalizing Connections

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Sh u td o w n Sta tio n

Sp ra y Fill

Va p o r Rise r

Pum p D isc ha rg e Auxilia ry Pum p In le t

Liq uid Un lo a d(C o m p re sso r)




Figure 14a. Bottom-Center Loading &

Unloading Valve Connections

Figure 14b. Rear Loading &Unloading Valve Connections


Withdrawal Connection

Figure 15. Internal Valves

LP-gasL iquid

LP-gasVapor Valve Disc

OperatingLever

Internal Valve

Cable Thermal Activation(Fusible Link)

LP-gasL iquid

LP-gasVapor Valve Disc

PneumaticOperatingCylinder

(Thermal Activation–Thermoplastic Air Line--Fusible Element)

Internal Valve



Figure 15a. Valve Closed(Position A)

Position A: When the operating lever is in the closed position, tank pressure (liquid or vapor) holds the main and pilot valves in the closed position.



Figure 15b. Bleed Open, Excess Flow Valve Closed

(Position B)

Position B: When the operating lever is moved to the open position, the cam moves the valve stem upward, opening the pilot valve orifice. Tank pressure bleeds through the pilot orifice and begins to build up downstream pressure.



Figure 15c. Valve Open(Position C)

Position C: As downstream pressure equalizes with tank pressure, the excess flow spring opens the main valve. The system is ready for transfer operations with the main valve acting as an excess flow valve. Releasing the operating lever to the closed position instantly closes both the main valve and the pilot valve (Position A).



Figure 16. Cable Installation



Figure 17. Pump Pressure Operated Internal Valve (Flanged)



Figure 18. Three-Way Valve


Relief Valves

Figure 19a. Internal Relief Valve

Figure 19b. Closed

Figure 19c. Open


Relief Valves

Figure 20. Relief Valve Caps and Covers

Relief valves are removed and independently tested as part of the cargo tank 5-year pressure test performed by a U.S. DOT Registered Inspector.


PTOs & Pumps

Figure 22a. Tractor PTO Output Shaft

Figure 22b. Connecting “Jack Shaft” Between Tractor and Trailer


PTOs & Pumps

PTO SHAFT HAZARDWARNING:

1. DO NOT attempt to connect or adjust the PTO shaft section between the tractor and trailer with the engine running.

2. NEVER place any body part, clothing, hair, or hand-held object (within 3 feet of) a rotating PTO shaft.


PTOs & Pumps

Figure 23. In-Cab Pneumatic PTO Control


PTOs & Pumps

Figure 24. Sliding Vane LP-Gas Pump


PTOs & Pumps

Figure 24. Sliding Vane LP-Gas Pump


PTOs & Pumps

Never allow the pump to run dry.Liquid LP-gas is the lubrication and cooling material that protects the pump from premature wear and failure.


Auxiliary Pump Inlet

Figure 25. Auxiliary Pump Inlet


Liquid Meters

Most transports are not equipped with a liquid meter. CTMVs in metered delivery service, however, have a liquid meter installed in the pump discharge line to account for the correct number of gallons delivered to customers.

To ensure accurate inventory records, deliveries of propane to bulk plants and industrial customers are adjusted so the invoice displays the volume of gas at 60° F.

Figure 26. State Weights & Measures Registration Decal on Meter Register


Transfer Hoses

Use of the vapor equalizing hose prevents or minimizes the following:

• excessive pump cavitation

• excessive pressure build up in the customer storage containers

• venting of relief valves on customer storage containers in hot weather or on ASME tanks that fill to the liquid space

Vapor Equalizing Hose – Typically attached to the plant transfer bulkhead, but on CTMVs in metered delivery service, may be carried on the transport


Transfer Hoses

Delivery Hose Assembly (Liquid) –

One of the most frequent causes of early failure of delivery hoses is damage from abrasion caused by vibrations of the hose.

When this condition is detected, there are two important steps to be taken at once. The hose must be inspected more frequently and the cause of the vibration should be determined and corrected. If wear is so extensive as to expose the hose reinforcing fabric, the hose cannot be used until it is repaired and pressure tested or replaced with a new hose.


Emergency Discharge Control Systems

U.S. DOT regulations require the installation of either off-truck remote emergency discharge control systems or passive shutdown systems.

MC 330, MC 331, and non-specification cargo tank motor vehicles …. must be retrofitted with required emergency discharge control equipment at their first scheduled pressure test after July 1, 2001. All required retrofits must be complete by July 1, 2006. There are three types of emergency discharge control systems used on transports:

• Manually actuated systems

• Off-truck remotely actuated systems

• Passive shutdown systems



Manually Actuated Systems

Figure 27a. Emergency Shutdown Station—Front Trailer Location

Figure 27b. Emergency Shutdown Station—Rear Deck Location



Off-Truck Remotely Actuated System

Figure 28. Example of Off-Truck RF Device



Passive Emergency Shutdown System – Passive emergency shutdown systems are systems that can stop the flow of product and stop the vehicle engine without human action within 20 seconds in the event of a complete delivery hose separation.

Figure 29a. Passive Shutdown System Control Box

Figure 29b. Discharge Line Sensor

2.3.1 Student Book © 2004 Propane Education & Research Council Pages 26 & 27

Pull-away Prevention Devices

Safety Air Brake Interlocks – The purpose of the interlocks is to prevent accidents such as moving the vehicle from a loading or unloading bulkhead with the PTO engaged or the hoses connected.

Figure 30. Undercarriage Interlock Gate Open for Loading


Cargo Tank Labeling & Marking

U.S.Department of Transportation regulations require specific cargo tank markings, including:

• Hazard Class Placards

• Product Shipping Labels

• Cargo Tank Inspection and Test Markings

• Quench Tempered or Non-Quench Tempered Markings

Placards and shipping labels (Figures 31 and 32) are required on the front, back and both sides.



Figure 31. Propane Shipping Label and Placard with LP-gas Identification Number



*Some states may require decals stating, "WE STOP AT RAILROAD CROSSINGS," to be placed on the rear of the vehicle.

Figure 32. Hazard Class Placards

Red Background

O rangeBackground

a. Com bined D O T/ U N P lacard b. Separate DO T

and UN P lacards

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Tests & Inspections – The month and year of the latest required annual cargo tank inspections and the test and inspections required every five years must be shown near the cargo tank data plate. All commercial motor vehicles must also pass an annual vehicle inspection. Documentation of the annual mechanical inspection may be in the form of a decal.

Cargo Tank Test and Inspections Annual Inspections 5-Year Test and Inspection • External visual inspection (V inspection), and • Leak inspection (K inspection).

• Hydrostatic pressure test (P test), and • Internal inspection (I inspection)

2.3.1 Student Book © 2004 Propane Education & Research Council Pages 29 & 30

Time to See If You Got the Key Points of This Module…

• Complete the Review on page 29.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 30.

Documents

2.3.1 Student Book © 2004 Propane Education & Research CouncilPage 1 2.3.1 Identifying Equipment & Procedures Used on Propane Transports Most of the propane