Sealing Options

Brazed seals have been the subject of extensive research and development, with only limited success to date. Normally, brazing involves application of elevated 

Solid-state brazing is simply a process of solid-state diffusion. Solid-state brazing occurs at a rate which is temperature dependent, meaning that less time is required to achieve a satisfactory solid-state diffusion bond at higher temperatures. To realize diffusion times of the order of a few hours, the temperature should be at least 500 °C, perhaps 600 °C and the parts (membrane and adjacent 

Brazing and welding use high temperatures to make seals to the membranes. The temperatures involved vary somewhat, depending on the process, but in almost all cases the temperatures required are greater than the operating tempera- 

The high temperature may strain the membrane (being the weakest material in the membrane module) and cause the membrane to tear or otherwise fail, or to be stretched, as was described above. 

Hunter, A new hydrogen purification process, Platinum Metals Rev. 1960, 4(4), 130-131. 

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Figure 12-51B. Shaft seal options. (Used by permission Bui. 2781005301, 1988. Atlas Copco ACT.)...

Compared to alkaline electrolysis, material costs are high for SPE electrolysers. The advantage of the SPE technology lies in a higher gas quality - especially in part load operation. Using a solid electrolyte also makes higher pressure possible as the absence of alkaline solution provides better sealing options. Some suppliers of SPE electrolysers are listed in Table 5.2. 

Sealing options. The GASPAC compressor gas seal line features a choice of the patented advanced pattern groove unidirectional face pattern and the bidirectional,... 

Various coupling designs are available to transmit torque from the driver, eg, electric motor, to a pump. In order to contain the pumped fluid inside the pump and prevent the pumpage from leaking, several types of sealing methods are used. A few options are described herein. 

Electrical Hazards. Because carbon fibers are conductive, the airborne filaments can create serious problems shorting out electrical equipment. The best option is to locate sensitive equipment in clean rooms outside of areas where carbon fiber is being processed. If this is not possible, electrical cabinets must be effectively sealed to prevent contact with carbon fibers. A filtered air-positive purge provides additional protection for sensitive equipment. 

The second option, dry face or gas seals, was developed in the early 1970s. In dry face seals, the hydrodynamic pressure that develops between the rotating and stationary seal faces produces positive sealing with minimal seal gas leakage. 

Designs differ eonsiderably from one manufaeturer to another. The term seal body makes referenee to all rotating parts on a pusher seal, exeluding shaft paeking and the seal ring. The eonfiguration or options offered on the seal body may be the ehief reason to avoid the design for that partieular serviee. 

Other options for eliminating weapons-grade plutonium arc to seal it permanently in solid radioactive waste and dispose of it in waste repositories, and to use the plutonium to fuel fast neutron reactors (without reprocessing the plutonium into a MOX fuel). 

This is essential on a sealed transformer and optional on a breathing unit. It can be fitted with contacts for remote alarm/tripping. 

A further options is to fill the dry, sealed boiler with nitrogen at 3 to 5 psig or dry steam at 5 to 15 psig. If steam is employed, traps on the mud drum or other lowest point remove the condensate. Steam storage has the benefit of keeping the boiler warm, which limits the risk of fireside dampness. 

A second option is to apply the membrane on the particle level (millimeter scale) by coating catalyst particles with a selective layer. As a third option, application at the microlevel (submicrometer scale) is distinguished. This option encompasses, for example, zeolite-coated crystals or active clusters (e.g., metal nanoparticles). Advantages of the latter two ways of application are that there are no sealing issues, it is easy to scale-up, the membrane area is large per unit volume, and, if there is a defect in the membrane, this will have a very limited effect on the overall reactor performance. Because of these advantages, it is believed that using a zeolite... 

The main components of an elevated flare system are the flare burner with or without smoke suppression capability, pilot(s), pilot igniter(s), support structure, and piping. A number of optional features are available, such as pilot flame detectors air seals (buoyancy or... 

On a rare occasion a tensioned string tied to pressure switch has been provided as detection over the vapor seal area of a floating roof crude storage tank. Although this method may be considered primitive and cheap, it is effective and beneficial versus the option of no detection). 

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