Manometer inclined

Inclined manometer A manometer in which the vertical movement of the liquid column is amplified by inclination of the U-shaped reading tube. 

Oil slant gauge An inclined manometer tube using oil as the measuring fluid to record the pressure. 

The static pressure within a duct is too small to he measured hy a hourdon tuhe pressure gauge, and the vertical or inclined manometer is usually employed (Figure 27.2). Also, there are electromechanical anemometers. The pressure tapping into the duct must he normal to the air flow. 

Half angle of triangular notch or angle made by inclined manometer lube with horizontal ... 

An inclined manometer is used to measure the pressure drop between two taps on a pipe carrying water, as shown in Fig. 4-P13. The manometer fluid is an oil with SG = 0.92, and the manometer reading (L) is 8 in. The manometer reservoir is 4 in. in diameter, the tubing is 4 in. in diameter, and the manometer tube is inclined at an angle of 30° to the horizontal. The pipe is inclined at 20° to the horizontal, and the pressure taps are 40 in. apart. 

Relative pressure device inclined manometer, across an orifice plate upstream of the fan. 

An inclined manometer is a useful device for measuring small pressure differences. 

An inclined manometer is often used to measure small pressure differences. See Fig, PI.91. 

One of fhe simplesf and mosf useful pressure measuring devices is fhe manomefer. There are several variations of fhe manomefer. In this section we will discuss two types U-tube and inclined manometer. 

For example, it is common to be able to measure the draft inside of a heater with an accuracy of 1/lOOth of an inch of water column (0.00036 psi). With U-tube monometers, it is not possible to read pressures this accurate instead, inclined manometers are commonly used. 

Inclined manometers essentially expand the scale of a U-tube manometer by orienting it at an angle, relative to the horizontal, as illustrated in Figure 4.4. Although the actual vertical rise of the liquid in the U-tube and inclined manometer are identical, the scale on the inclined manometer is spread out over a much larger horizontal distance this expanded scale increases the instruments accuracy. 

Inclined manometers consist of a clear tube positioned at a slight angle relative to the horizontal as shown in Figure 4.5. The tube is typically filled with red oil with a specific gravity of approximately 0.8. Located at the top of the manometer are two pressure taps a high pressure side and low pressure side. The low pressure side tap contains the oil reservoir. For accurate measurement it is important that the manometer is level with the horizontal. Typically inclined manometers are designed with a bubble level to assist in accurate leveling. 

Showing how an inclined manometer expands the measurements scale. 

A velocity thermocouple (also known as a suction thermocouple or suction pyrometer see Chapter 5) was used to measure the furnace and stack gas temperatures. The furnace draft was measured with an automatic, temperature-compensated, pressure transducer as well as an inclined manometer connected to a pressure tap in the furnace floor. Fuel flow rates were measured using... 

Inclined manometer. The tubes on each side of the manometer are connected to pressure taps (or one is open to atmosphere). The difference in liquid columns is measured with a ruler calibrated for the inclination angle. 

For low pressure differences, the inclined manometer shown in Fig. 2.36 is often used (this device is used so often to measure the draft of a furnace that its common name is a draft tube). If the scale is set to read zero length at P = P and the manometer fluid is colored water, what will the reading be at - Pg =0.1 Ibf/in What would be the reading of an ordinary manometer with vertical legs for this pressure difference ... 

Visualizing furnace pressure requires measuring it by an inclined manometer with one leg connected to a tap through the wall to the furnace interior and the other manometer tap simply receiving pressure from the atmosphere just outside the furnace. To control the effects of furnace pressure, one must determine the elevation within the furnace of the zero pressure level (i.e., zero AP inside to outside the furnace) and understand how it affects interior furnace gas flows. (See pp. 58-69 of reference 52.)... 

Figure 11.2 Inclined manometer used as a filter loss gage. Source Courtesy of Airflow Developments Ltd.

The draft is a result of the density difference between hot flue gas in the heater stack and the cooler ambient air. Therefore, the hotter and taller the stack, the greater the draft. Draft is measured with a water-filled inclined manometer. 

Special types of manometers sometimes used for more accimate measurement include the inclined manometer, the micromanometer, and U tubes installed with hook gauges, as well as many special types of manometers for vacuum measurement, which will be mentioned later. 

An inclined manometer (Fig. M-12) is a manometer inclined at an an e with the vertical. Although the vertical displacement is still the same, the movement of liquid along the tube is greater in proportion to the secant of the angle. The common form of inclined manometer is made with a cistern, as shown in Pig. M-12. 

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