We show in figure 8 how these meters are calibrated, The prover tank shown here is owned by the terminal operator. Semiportable, it can be moved to any truck loading position and a test delivery made that duplicates in every way the actual delivery to the truck tank. The capacity of the tank is 500 gallons, the meters operate at less than 350 gallons per minute, and accurate testing is possible.

Figure 9 shows another terminal test procedure. Here deliveries are made to trucks at rates of 400 gallons per minute. A 400-gallon prover tank is shown receiving a test delivery in the same manner as the delivery would be made to a truck tank.

At the modern terminal shown in figure 10 the owner has installed a 500-gallon permanent prover tank that is available for test runs at any time. The flow of any meter can be diverted to the prover tank and an immediate test made to prove the accuracy of the meter. A permanent prover has an advantage in the event the accuracy of a delivery is questioned, for immediate test runs can be made to prove the accuracy of the meter.

Figure 11 shows a permanently installed closed-type prover at a pipe-line terminal which is used for calibration of the meters on the loading rack in the background. Interconnecting piping will divert the flow of any meter to the proving tank. You will note that here again ample capacity has been provided in the prover tank. Of further interest, here are the two meters shown in the foreground. Since the State gasoline tax to be paid by this terminal is determined by the total readings of each loading-rack meter, it is necessary that the volume of fluid used in testing be deducted. The two meters in the foreground record the discharge from the prover tank, one meter registering the taxable product discharged, and the other the nontaxable products such as fuel and diesel oils. The reading of the discharge meter on taxable products is deducted from the reading of the delivery meters in computing the tax.

I have been asked to comment on a new development of the meter manufacturers that permits the placing of the ticket printing device in the office at a remote point from the meter installation. (See fig. 12.) This system is finding wide acceptance, as it limits the duties of the truck loader and places all accounting functions in the office. Weights and measures officials have inquired as to the accuracy of these devices. Examinations of the various systems offered indicates that under no circumstances can a buyer be charged with more product than he receives. Any attempt to interfere with the system operation will in most cases result in no registration whatever.

Several weights and measures departments such as Massachusetts, Connecticut, and Los Angeles have constructed large test units that are adequate for testing meters of any size now in service. I do not have pictures of these units to show you, but I believe photographs have appeared in weights and measures publications. I would caution that in the absence of test equipment of adequate size, tests should not be made in small equipment unsuited to this work. The rule that the test draft must equal one minute's operation of the meter at normal speed is worth following. Instances are known where carefully calibrated truck compartments are used as prover tanks. This expedient, while more desirable than the use of prover

customers' plants.

FIGURE 7.

Modern bulk-plant installation. Meters are mounted under the working floor. Printing-type counters and set-stop counters for automatic loading are extended above the working floor.

FIGURE 8. This type of prover tank is used by the terminal operator, and can be moved to any truck-loading position.'

Semiportable prover tank, capacity, 500 gallons.

FIGURE 10. Permanently installed 500-gallon prover tank.

The flow from any meter can be diverted to the prover tank for an immediate test on the accuracy of the meter.

FIGURE 11. Permanently installed closed-type prover tank at a pipe-line terminal. Interconnecting piping will divert the flow from any meter on the loading rack (shown in the background) to the prover tank.

tanks of inadequate size, does present some hazards. The compartment should be as large as possible to minimize the possible error in reading the liquid level at the compartment marker. Tests have been made by first making a delivery to the truck compartment, and then making a series of withdrawals to small calibrated containers.

I have emphasized this problem of the size of test equipment because it is the outstanding hazard in testing large-capacity meters. In general these installations will be found well engineered. The design of many installations is such that air entrainment is minimized to the point where air elimination equipment is not provided. This attention to engineering design simplifies the problems of the weights and measures man and makes the actual proving of the meter a routine test for quantity delivery.

I wish to thank the officers of this Conference for the opportunity to

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