Good Features in New Fuel and Oil Meters
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SEVERAL interesting features are to be found in a new range of meters for the measurement of fuel and Willicating oils, petrol, etc., now being marketed • by Precision Meters, Ltd., 104, High Holborn, London, W.C.I. Known as the Victory meters, they are available in two types.
The first is made in two sizes having capacities of two gallons to 300 gallons per hour, and 300 gallons to 1,000 gallons per hour respectively. A sectional view of one of these instruments accompanies this article. In operation, the liquid enters one side of the meter through an accurately machined piston valve. The valve provides a common member for the inlet and discharge ports and thus loads the measuring chamber.
How Measurement is Effected.
The measuring device is contained within this chamber, and comprises a reciprocating double action plunger which displaces the liquid, causing an amount equal to the displacement to be delivered through the discharge port. When the plunger reaches the end of its stroke a rocker-arm member automatically reverses the centrally placed valve so that the inlet port becomes the discharge port and vice versa.
In conjunction with the rocker arm is a dashpot and piston, which comes into effect at the extreme end of the calibrated stroke. This piston traps a constant amount of liquid and constitutes the stop for the stroke • of the pluaer. Since this fluid is replaced every stroke wear is minimized and the calibration remains constant.
The recorder indicates fractions of a. • gallon as the plunger comes to the end .• of its stroke, and a five-figure totaliser is incorporated which gives the complete figure in gallons of the liquid measured. If another unit of measurement be required this can easily be arranged.
Tests by the National Physical Laboratory have shown that the meter reading is within 0.45 per cent, of dead accuracy, and this figure is well within the limits laid down by the Board of Trade. The respective prices Of this model are £12 and £16.
Positive Displacement.
The second meter is also available in two sizes having capacities of 50 gallons per hour and 180 gallons per hour. This instrument is of the positive-displace, ment multi-piston type. It is balanced under pressure and, being valveless, is positive in action, giving accurate , readings under varying, or any given,pressure.
There are three separate chambers— inlet, mechanism and delivery—and, since the mechanism chamber is isolated and is not under pressure, gland adjustment is unnecessary. The pistons are four times the length of their working stroke, and have a semi-rotary,. .in additionto a reciprocating, Inoverncrit,.
This meter is particularly suitablefor delivery of lubricating oils and .is itt extensive use for dispensing units arid cabinets.