Orifices, opening

FIG. 10-18 Square -edged or sharp-edged orifices. The plate at the orifice opening must not be thicker than one-thirtieth of the pipe diameter, one-eighth of the orifice diameter, or one-fourth of the distance from the pipe wall to the edge of the opening, (a ) Pipe-line orifice, (h ) Types of plates. 

Knowing the bottomhole pressure, the number of bit orifice openings and the inside diameter of these openings, the pressure inside the drill pipe just above the bit and the surface injection pressure can be found. 

From Equation 4-129 the total area of the orifice openings is... 

The interface with the process at the other end of the control loop is made by the final control element. In a vast majority of chemical engineering processes the final control element is an automatic control valve which throttles the flow of a manipulated variable. Most control valves consist of a plug on the end of a stem that opens or closes an orifice opening as the stem is raised or lowered. As sketched in Fig. 7.5, the stem is attached to a diaphragm that is driven by changing air pressure above the diaphragm. The force of the air pressure is opposed by a spring. 

Orifice openings shall not be less than 3 mm (0,12in) in diameter. 

Two-stage rotors are also available for continuous mixers (Fig. 22), which incorporate a second screw section to enable down-stream feeding of additives such as heat or shear sensitive fillers, or extraction of volatiles from the mixture [147]. For a fixed rotor geometry, rotor speed, fiow rate, barrel temperature and orifice opening are the principal operational variables which control mixing intensity. 

For a given type of solids, the control variables of the standpipe system are the orifice opening and the pressure drop from the top of the hopper to the bottom of the orifice. 

By jet velocity is meant the value of the average velocity at the vena contracta. The velocity profile across an orifice opening such as that shown in Fig. 10.5a is seen to be nearly constant except for a small annular ring around the outside. The average velocity V is thus only slightly less than... 

Generally, the conductance of a tube or a duct can be regarded as the conductance of the tube/orifice opening (Cap) multiplied by a probability factor representing the proportion of particles leaving the exit of the conductance ... 

As explained in Chapter 17 die configurations meet certain melt flow requirements such a drawdown ratio and draw ratio balance. Draw-down ratio (DDR) in a circular die, such as a wire die, is the ratio of the cross sectional area of the die orifice/opening to the final extruded shape. Another guide for setting uniformity and best repeatable references is the draw ratio balance (DRB) that aids in determining the minimum and maximum values that can be used for different plastics. 

The drawdown ratio (DDR) in a wire die or a circular die, is the ratio of the cross sectional area of the die orifice/opening to the final extruded shape [Figure 17.13(b)]. 

Orifice is square-edged with throat taps Diameter of orifice opening s 1 in. 

Orifice baffles should be spaced reasonably close together to produce frequent increases in fluid velocity through the orifice openings between the tubes and the baffles. This type of baffle should not be used for fluids with high fouling characteristics. 

Let l pi, be the / of the orifice opening at the maximum peak flow through the channel. The corresponding h would be h p - From Equation (5.23),... 

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