High working pressures

Deepwater applications entail very high working pressures and temperatures and harsher environments. This has led to the development of hyperduplex stainless steels, which have better yield... 

It is possible, particularly for distillation processes at high working pressure, for the critical pressure of either one or both components to be lower than the working pres-... 

The choice of the adhesive determines the type of application equipment required. For most industrial applications, pump-operated applicator systems are used which are designed to pump the adhesive directly from bulk drums at relatively high working pressures. Systems for using hot-applied adhesives need to be equipped with heated follower plates, hoses and guns. For automated application, additional dispensing units are necessary to meter the exact quantity of adhesive required for each application. 

A somewhat different type of high pressure reaction vessel is illustrated in Figs. VI, 4, 3-5. This is designed for hydrogenation reactions at working pressures from 1 to 300 atmospheres (4,500 lb. per square inch) and at temperatures from atmospheric up to 400°. Fig. VI, 4, 3... 

Hot (230-240°F) potassium carbonate treating was patented in Germany in 1904 and perfected into modem commercial requirements by the U.S. Bureau of Mines. The U.S. Bureau of Mines was working on Fischer-Tropsch synthesis gas at the time. Potassium carbonate treating requires high partial pressures of CO2. It therefore cannot successfully treat gas containing only H2S. ... 

Any obstruction inserted into a duct or pipe that creates a measurable pressure difference can be used as a flow meter. The three basic standardized flow measurement devices presented above are perhaps more suitable for laboratory work than installation as permanent ductwork instruments in ventilation applications. They are sensitive to flow disturbances, relatively expensive, require considerable space, and have a narrow measurement range and a high permanent pressure loss. For these reasons, numerous attempts have been made to develop instruments without these drawbacks. Some of them, like the... 

Pressure burst A failure in a filter, duct work, or an air handling unit due to high differential pressure. 

The primary protection for high temperature, which could lower the maximum allowable working pressure below the PSV setting, is a high-temperature sensor (TSH), which shuts in the inlet or the source of heat. Back-up protection is provided by leak detection devices. 

Once the FMEA is completed, the specific system is analyzed to determine if all the devices are indeed needed. For example, if it is not possible for the process to overpressure the vessel, these devices are not required. If it is impossible to heat the vessel to a high enough level to effect its maximum working pressure, the TSH can be eliminated. 

The pressure at which the valve is expected to open (set pressure) is usually selected as high as possible consistent with the effect of possible high pressure on die process as well as the containing vessel. Some reactions have a rapid increase in temperature when pressure increases, and this may fix the maximum allowable process pressure. In other situations the pressure rise above operating must be kept to some differential, and the safety valve must relieve at the peak value. A set pressure at the maximum value (whether maximum allowable working pressure of vessel, or other, but insuring protection to the weakest part of the system) requires the smallest valve. Consult manufacturers for set pressure compensation (valve related) for temperatures >200°F. 

There are two possible causes. The first could be incorrect control of water treatment and blowdown. This can result in excessive levels of suspended solids in the boiler water, organic matter in the boiler water or high alkalinity. The second can be mechanical. If the boiler is operated below its designed working pressure it will increase the efflux velocity of the steam leaving the water surface area to a point where it may lift the water surface and drop the water level. It is important therefore to give due consideration to the steam load required from the boiler. 

In twin-flue design, these figures are approximately double. Normal working pressures of 10-17 bar are available with a maximum working pressure for a shell boiler at 27 bar. The outputs of larger boilers will be limited if high pressures are required. 

Fluid power encompasses most applications that use liquids or gases to transmit power in the form of mechanical work, pressure and/or volume in a system. This definition includes all systems that rely on pumps or compressors to transmit specific volumes and pressures of liquids or gases within a closed system. The complexity of these systems range from a simple centrifugal pump used to remove casual water from a basement to complex airplane control systems that rely on high-pressure hydraulic systems. 

Convenient working pressures, i.e. not too high and preferably not below atmospheric pressure... 

A high latent heat of vaporization A high density of suction gas Non-corrosive, non-toxic and non-flammable Critical temperature and triple point outside the working range Compatibility with component materials and lubricating oil Reasonable working pressures (not too high, or below atmospheric pressure)... 

In addition to developing solid RP structures, work has been conducted on sandwich structures such as filament-wound plastic skins with low-density foamed core or a plastic honeycomb core to develop more efficient strength-to-weight structures. Sandwich structures using a syntactic core have been successfully tested so that failures occurred at prescribed high-hydrostatic pressures of 28 MPa (4,000 psi). 

Pd = ASME Code design pressure (or maximum allowable working pressure), psi Pdo = pressure on outlet side of rupture disk, psia Pe = exit or back pressure, psia, stamped burst pressure Per = perimeter of a cross section, ft or meters Pn = Initial high pressure, mmHg Pj = maximum initial pressure at which the combustible atmosphere exists, psig P j = initial pressure of system, psia PL = initial low pressure or vacuum, mmHg Pmax =- maximum explosion pressure, bar, or other consistent pressure units... 

---