High-pressure machines

Because of severe stresses, it is essential to design and fabricate high-pressure machines very carefully. 

The problem- points in high-pressure machines are certainly the dynamic shaft- and piston-or plunger seals. Seals create special problems when they slide rapidly under high-pressure and if the fluid being sealed has no lubricating actions. Cyclic stress creates additionally fatigue problems in the seal. 

Reciprocating compressors are relatively low flow rate, high pressure machines. Pressures as high as 35,000-50,000psi are... 

High Pressure Machine Engineered Pressure Systems, Inc. Instant nonfat milk, spray-dried coffee and freeze-dried coffee... 

An illustrative example may help to emphasize this need, In converting an analytical mass spectrometer into a high-pressure machine, the present author obtained excellent agreement for the rate constant of the reaction CH4" (CH4,CH3)CH5 with the then currently accepted values, " Subsequent direct measurement of ion residence times showed that field penetration was severe and the source most unsuitable for rate constant measurements. Such findings are to be expected for analytical instruments where the design criterion is to maximize the ion signal and not to optimize the conditions for a rate measurement. 

Threads can be cast on high-pressure machines but should be specified only where their use reduces cost over that for machine-cut threads. Cast internal threads under 20 mm in diameter are rarely economical. 

The cost of die-castings can be low, due to very rapid fully automated production over long periods. High-pressure machines, e.g. can operate at rates in excess of 500shots/h. 

Machine runs for the MDI flexible moulded foam were conducted on a Krauss-Maffei, cylinder displacement series, high pressure machine. Fresh premixes, consisting of the appropriate polyols, water, crosslinker, surfactants and catalysts for each formulation were charged to the machine. Modified MDI was used throughout the entire study. All chemical temperatures were held at 25 °C 2 °C via the machine s internal temperature control units. Foam pours were made into an isothermally controlled heated aluminium mould maintained at 60 °C 2 °C. The mould was a typical physical property tool designed with... 

AHTR Sizing. The initial assumption was that the AHTR vessel would be the same size as the General Electric S-PRISM vessel. Both reactors are low-temperature high-pressure machines. 

Figure 13.3 Selection of materials for high-pressure machines (a) Woehler curves for a duplex steel with different test media, (b) von Mises equivalent stress in notched fatigue samples and other specific values R=Sb/Sm (S[, minimum of amplitude S,. maximum of amplitude). R=— 1 rotating...

The constructive rules for high-pressure components and especially for those under dynamic stress are as follows as few notches as possible (cross bores, steps, and edges), smooth surface, ductile materials, and pressure-loaded chambers as small as possible. The figures as described in the following show examples of high-pressure machines that were put into practice. 

---