Gauge corrections

A complete check against all rubber lining details on customer drawings and specifications should be made to ensure the rubber lining has been applied to the proper areas and with the correct gauge stock. 

Because of the elements in the detector s circuit (Figure 6.10), it has a capacitive-resistive impedance Z that must be correctly gauged in order to achieve a much faster... 

On many pieces, it is desirable to gauge the first flange on a backgauge. Next, the piece must be flipped and rotated. This is required in order to maintain the correct gauging surface against the backgauge for critical dimensions. With the front rear combination, the part must still be flipped, but rotation can be eliminated. 

The examples shown in Fig. 21 are typical of many systems, but in order to correctly gauge which mesophases will be formed and lost, the temperature range of the liquid crystal state should be taken into account for each compound. For instance, the last material given in the above example exhib-... 

For records on weather maps, meteoroiogists customariiy correct barometer readings to sea ievei, and some barometers may be caiibrated accordingiy. Such instruments are not suitabie for iaboratory use where true pressure under standard conditions is required. Scaie corrections shouid be specified in the maker s instructions with the instrument, and are aiso indicated by the iack of correspondence between a gauge mark usuaiiy piaced exactiy 76.2 cm from the zero point and the 76.2-cm scaie graduation. 

Pressure and Vacuum. Pressure is usually designated as gauge pressure, absolute pressure, or, if below ambient, vacuum. Pressures are expressed in pascals with appropriate prefixes. When the term vacuum is used, it should be made clear whether negative gauge pressure or absolute pressure is meant. The correct way to express pressure readings is "at a gauge pressure of 13 kPa" or "at an absolute pressure of 13 kPa."... 

The easiest thing to do is to get the pump curve from the manufacturer because it has the NPSHr listed at different flows. Nowadays, you can get the pump curve on the Internet with an e-mail to the manufacturer, you can send a fax, or request the curve in the mail or with a local call to the pump representative or distributor. If you wanted to verify the NPSHr on your pump, you ll need a complete set of instrumentation a barometer gauge, compound pressure gauges corrected to the centerline of the pump, a flow meter, a velocity meter, and a thermometer. Definitely, it s easier to get the curve from your supplier. 

Effective and well planned maintenance can reduce the operating cost of your pumps and other ec]uipment as this example demonstrates. With differential pressure gauges on the pump, an amp meter and flow meter you can determine if strict tolerance parts arc worn. This indicates the need to take the pump into the shop for corrective procedures. If you don t do it, you are wasting your annual operating budget. As we mentioned in Chapter 6, the Wear Rings should be called Efficiency Rings. Now you know why. 

Trouble Chart Readings Apparentiy Not Correct or Not Consistent with Local Gauges. 

Note The curves above represent a compromise of the values recommended by a number of relief valve manufacturers and may be used when the make of the valve or the actual critical f ow pressure point for the vapor or gas is unknown. When the make is known, the manufacturer should be consulted tor the correction factor. These curves are for set pressures of 50 pounds per square inch gauge and above. They are limited to back-pressure below critical flow pressure for a given set pressure. For subcntical flow back-pressures below 50 pounds per square inch gauge, the rnanufacturer must be consulted tor values of Kk. 

Figure 10-50B. Heat transfer film coefficient for water flowing inside 1 in. X 18BWG tubes referred to outside tube surface area for plain tubes. Note the corrections for tubes of wall gauges other than 18 BWG. (Used by permission J. B. Co., Inc., Western Supply Div., Tulsa, Okla.)...

Pressure gauges contain a partly coiled, hollow tube (Bourdon tube) that further coils or uncoils in response to the pressure of the steam or water contained within the tube. Pressure gauges reading below the steam and water line must be corrected by 0.433 psig per vertical foot to take account of hydrostatic pressure ... 

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