Blow out preventers

The tubular-film process is only suitable for materials with sufficient melt strength to prevent blow-out of the balloon. Hence, grades with a higher molecular weight are sometimes used and the mass temperature is often 20-30°C lower than in flat-film extrusion. A low mass temperature is also required to decrease the height of the frost line, which results in a more stable balloon. 

Gas now enters the system initially through finely controlled needle valves (to prevent blow-out of the carbon sample from the bucket, and vibration of the spring) to commence the adsorption process. As the carbon adsorbs the gas (the adsorptive) its weight increases... 

Note A3.1—Probe installation and operation are covered in A3.9. As a safety precaution, the probe should be installed and removed during low pressure conditions. However, the probe should be equipped with safety chains and stops to prevent blow-out should it be necessary to remove it during operation conditions. 

Pressure test piping and equipment Flush and clean piping and equipment Drain water to prevent freezing Blow out piping Continuity testing with air... 

The main risk in the manufacture of propellants is that of fire and only in isolated circumstances is there also a detonation risk. A common construction of a building is therefore of reinforced concrete, and frequently one single building contains a number of compartments separated by strong partition walls. Each compartment will, however, have a blow-out panel of large size and flimsy construction. Should a fire occur the panel blows out and prevents any build up of pressure which could cause the deflagration to become more severe. 

Problems similar to this are usually identified in safety reviews. This accident, for example, could have been prevented if the plant had used a safety review procedure during the design phase of this plant modification. A bleed line and possibly a nitrogen blow-out line would have prevented the accumulation of this water. 

The pressure in condenser A is greater than that in the surface condenser, and less than that in the final condenser (condenser B). This means that condenser A is operating at vacuum conditions. This prevents the condensed steam formed in condenser A from draining out to atmospheric pressure, unless the condenser is elevated by 10 to 15 ft. To avoid this problem, the condensate is drained back to the lower-pressure surface condenser. To prevent blowing the noncondensable vapors back to the surface condenser as well, a loop seal is required. The height of this loop seal must be greater than the difference in pressure (expressed in ft of water) between the surface condenser and the primary jet discharge condenser (condenser A). 

Safety considerations (increased risks resulting from concentrating storage capacity in a small number of large facilities), as well as performance reasons (the flow is limited by pressure loss in the wells) made it appear that the maximum possible volumes (400,000 - 600,000 m3) had been reached in Europe where well diameter is limited by the installation of a buried blow-out preventer (SSV for Subsurface Safety Valve). 

This cycling can be eliminated by mounting the control valve in the condensate pipe, but this creates new problems, because when the load decreases, the process is slow steam has to condense before the condensate level is affected, and when the load increases, the process is fast, because blowing out liquid condensate is fast. With such "nonsymmetrical" process dynamics, control is bound to be poor. A better option is to use lifting traps to prevent condensate accumulation. These pumping traps will make temperature control possible even when the heater is under vacuum, but will not improve the problem of low rangeability, and the possible use of two control valves in parallel can still be necessary. 

Expansion joints Diaphragms Blow-out preventers Valve seats Gaskets Hose... 

To prevent the risk of a gas leak, the drill-hole head is equipped with a blow-out preventer. This device is similar to that used on oil wells to avoid this type of leak, which in their case constitutes a threat of explosion or fire. In fact the risk of leakage is limited in a radiochemical sampling drill-hole, as the gas formed at the moment of the... 

The blow-out preventer also enables any drilling fluid returns from the cavity to be controlled and the waste to be limited to negligible quantities without radiological consequences. Waste of this type is responsible for the traces of iodine-131 detected in the Mururoa lagoon in the proximity of a sampling drill-hole by Mr. Cousteau in 1987. 

Bulking agents are intended to be inert and simply function as fillers to increase the density of the product cake. Product elegance is improved and product blow-out is prevented, but the bulking agent is not... 

Use of safety and first-line defense blow-out prevention equipment... 

Care should also be taken when inserting and retracting the probes to prevent injury. The probes are long and get very hot inside the oxidation chamber. Furthermore, conditions may exist where hot gases blow out of the sample port. Adequate personal protection equipment and proper procedures need to be followed when taking samples. 

---