Open ends Pressure

Probably the largest compound vessels built were two triple-wall vessels, each having a bore diameter of 782 mm and a length of 3048 mm designed for a pressure of 207 MPa (30,000 psi). These vessels were used by Union Carbide Co. for isostatic compaction unfortunately the first failed at the root of the internal thread of the outer component which was required to withstand the end load (40). A disadvantage of compound shrinkage is that, unless the vessel is sealed under open-end conditions, the end load on the closures has to be resisted by one of the components, which means that the axial stress in that component is high. 

Rupture discs on pressure relieve valves and plugs in open ended valves can reduce fugitive emissions. 

Figure 1. Available pressure drop may in some cases dictate acceptance of a lower maximum velocity, but at least 75 m/s is recommended to insure good dispersion. Flare tips consisting of a simple open-ended pipe with a single pilot are subject to flame lift-off and noise problems at lower velocities, and should therefore be designed for a maximum velocity of 50 m/s.

A hollow-fiber reverse-osmosis module consists of a shell which houses the hollow fibers (Fig. 11.3). The fibers are grouped together in a bundle with one end sealed and the other open to the atmosphere. The open ends of the fibers are potted into Ml epoxy sealing head plate after which the permeate is collected. The pressurized feed solution (denoted by the shell side fluid) flows radially from a central porous tubular distributor. As the feed solution flows around the outer side of the fibers toward the shell perimeter, the permeate solution penetrates through the fiber wall into the bore side by virtue of reverse osmosis. The permeate is collected at the open ends of the fibers. The reject solution is collected at the porous wall of the shell. 

Piezometer tube An open-ended calibrated glass or plastic tube that measures the pressure in a pipe or vessel full of a fluid. 

It is almost impossible to completely clean pipes that have contained heavy oils or polymers. When demolishing old pipelines, there should be as many open ends as possible so that pressure cannot build up. And good access should be provided so that the burner or welder can escape readily if he or she needs to do so. 

It must now be tested to see that it is air-tight. For this purpose, close the open end of the potash apparatus with a tight stopper and turn on the full pressure from either gasholder. After the first few bubbles of air have passed through the bulbs of the potash apparatus no further movement of bubbles should appear in any art of the apparatus. If it withstands this test, the combustion may proceed. Release the pressure by closing the tap of the gas-holder, screwing i p the... 

Bernoulli and Euler dominated the mechanics of flexible and elastic bodies for many years. They also investigated the flow of fluids. In particular, they wanted to know about the relationship between the speed at which blood flows and its pressure. Bernoulli experimented by puncturing the wall of a pipe with a small, open-ended straw, and noted that as the fluid passed through the tube the height to which the fluid rose up the straw was related to fluid s pressure. Soon physicians all over Europe were measuring patients blood pressure by sticking pointed-ended glass tubes directly into their arteries. (It was not until 1896 that an Italian doctor discovered a less painful method that is still in widespread... 

The expansion of a balloon when it is inflated is evidence of the pressure exerted on the interior walls by molecules blown into the balloon. If you tie off the open end of the balloon, you can squeeze the bal-... 

This sonic velocity occurs in a pipe system in a restricted area (for example, valve, orifice, venturi) or at the outlet end of pipe (open-ended), as long as the upstream pressure is high enough. The physical properties in the above equations are at the point of maximum velocity. 

Fig. 4-2. Pressure measurement. A. Barometer pressure — 755 mm. B. Closed-end manometer pressure = 105 mm. C. Open-end manometer pressure = 755 — 650 - 105 mm.

Repeat Problem 9 but with an open-end manometer (see Figure 4-2C). Atmospheric pressure is 760 mm. 

When water (a Newtonian liquid) is in an open-ended pipe, pressure can be applied to move it. Doubling the water pressure doubles the flow rate of the water. Water does not have a shear-thinning action. However, in a similar situation but using a plastic melt (a non-Newtonian liquid), if the pressure is doubled the melt flow may increase from 2 to 15 times, depending on the plastic used. As an example, linear low-density polyethylene (LLDPE), with a low shear-thinning action, experiences a low rate increase, which explains why it can cause more processing problems than other PEs. The higher-flow melts include polyvinyl chloride (PVC) and polystyrene (PS). 

The pitot tube is used to measure the difference between the impact and static pressures in a fluid. It normally consists of two concentric tubes arranged parallel to the direction of flow the impact pressure is measured on the open end of the inner tube. The end of the outer concentric tube is sealed and a series of orifices on the curved surface give an accurate indication of the static pressure. The position of these orifices must be carefully chosen because there are two disturbances which may cause an incorrect reading of the static pressure. These are due to ... 

For the flow not to be appreciably disturbed, the diameter of the instrument must not exceed about one-fiftieth of the diameter of the pipe the standard instrument (diameter 7.94 mm) should therefore not be used in pipes of less than 0.4 m diameter. An accurate measurement of the impact pressure can be obtained using a tube of very small diameter with its open end at right angles to the direction of flow hypodermic tubing is convenient for this purpose. The static pressure is measured using a single piezometer tube or a piezometer ring upstream at a distance equal approximately to the diameter of the pipe measurement should be made at least 50 diameters from any bend or obstruction. 

FIGURE 4.7 (a) In Boyle s experiment, a gas was trapped by mercury inside the closed end of a J-shaped tube. (b)The volume of the trapped gas decreased as the pressure on it was increased by adding more mercury to the open end of the tube. 

F(r, ffl ) represents a normalized square of the acoustic pressure of mode n at the position of the flame front. It is plotted in Figure 5.1.12 for the first two acoustic modes of the tube. This function goes to zero at the open end of the tube, which is a pressure node. For the fundamental mode of the tube, the gain remains small until the flame has traveled at least halfway down the tube. 

Ultrafiltration processes (commonly UF or UF/DF) employ pressure driving forces of 0.2 to 1.0 MPa to drive liquid solvents (primarily water) and small solutes through membranes while retaining solutes of 10 to 1000 A diameter (roughly 300 to 1000 kDa). Commercial operation is almost exclusively run as TFF with water treatment applications run as NFF. Virus-retaining filters are on the most open end of UF and can be run as NFF or TFF. Small-scale sample preparation in dilute solutions can be run as NFF in centrifuge tubes. 

For an open-ended cylinder, the critical pressure to cause buckling Pc is given by the following expression see Windenburg and Trilling (1934) ... 

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