Submergible pump

Assembly of magnetic recording heads Sealing stainless steel shells on submerged pump motors Bonding stranded wire ends Bonding thermal and electronic insulators... 

The cavern is constructed by mining out a porous mineral such as limestone, shale or chalk well below the water table. The roof and sides of the cavern are supported by multiple plastic coatings to prevent rock falls. The cavern is sealed hydro-dynamically with the pressure of water entering the cavern balancing the LPG pressure. A well in the lowest part of the cavern contains a submerged pump which pumps excess water to the surface. LPG is removed by pumps higher in the well. 

Cool-down of the dewar and its submerged pump and turbine-type flow meter measurement and efflux piping was accomplished in 8 min with 200 gal of liquid hydrogen. This was vented through a 5-in.-diameter stack at an initial 800 fps velocity which reduced to 10 fps at respective temperatures of efflux of —280 to —360°F. Average boil-off due to heat leak was 8.3 gal/hr. 

S. C. Kennedy, T. H. F. Tan, M. L. Taylor, and B. H. Tan. Submergible pumping system with thermal sprayed polymeric wear surfaces. US Patent... 

Submerged pumps are also frequently used to avoid problems from leaks from shaft seals. They should be stored well supported at both ends and aU openings should be kept closed when not in use. 

Capacity curves—volume, discharge pressure, power required as per purchase order Depth of submergence—for submerged pumps Discharge pressure (rated)... 

The internal circulating nozzle, or immersed column, is similar to the external circulating nozzle except that all the action takes place within the column. This is a vertical column with a small diameter central axial injection tube. Liquid is pumped from a submerged pump to the top of the tube compressed air is introduced at the top of the tube and the two phase mixture is injected down the tube and into the bottom of the vessel. 

Submerged pump can be provided but separate U-seal piping is required for exit liquor to prevent gases coming out from the tank. 

Spillages from the tanker and leaks from pipes and valves may be collected in a small tank (with suitable lining) kept at ground level. It can be emptied out by a small submerged pump in the tank. It is not advisable to use compressed air to empty out the tank because it might have got corroded in humid weather and can burst due to the applied air pressure. 

Such work frequently has to be performed when sealing submerged pumping stations. If a pumping station pumps fecal material, the concrete loses density and strength because of gas corrosion. In emergency switch-off of power, the pumps overflow with fecal matter. 

The ultimate simplification of the suction connection is to eliminate it with a submerged pump, and this is a very frequently used arrangement. The connection at the top of the tank then becomes a discharge line, and the pump mounting itself is another connection. These usually are grouped with others on a manway cover in order to reduce the number of penetrations of the vessel wall. 

Another problem with submerged pumps is the amount of chlorine that cannot be removed from the tank by pumping. First, the pump and its inlet must ride some distance above the bottom of the tank. Second, suction head requirements prevent pumping down to the pump inlet level. When emptying a tank, operators must first rely on removing the last of the liquid through a dip pipe. This might be under the influence of the liquid s vapor pressure or with the aid of a dry gas pad. Complete removal of chlorine to allow maintenance or tank entry always requires evacuation or gas displacement to remove the vapor and the last traces of liquid. 

Another alternative to the submerged pump in the storage tank is a submerged pump in a much smaller tank connected to the large tank by a top-connected suction line [69]. This removes the necessity of taking the large storage tank out of service... 

A submerged pump was used to collect spent fuel pool water samples from a depth of 3 m and from close to the coupon rack. The following parameters were measured without pretreatment ... 

Notes 1. Reservoir 2. Submerged pump 3. Pressure gage 4. Sprinkler 5. Model box 6. Slope model 7. Grit chamber 8. Camera observatory 9. Camera. 

Completely submerged pumps can also be used but only for water, since they can easily be damaged or suffer from corrosion in case ofcorrosive fluids like sulphuric acid and oleums. These pumps do not require gland packing and priming tanks. Net Positive Suction Head (NPSH) is always available since... 

Especially critical in fire pump installations from open bodies of water is the activity of underwater diver operations in close proximity of the underwater fire pump suction bell or opening. Underwater diving operations routinely occur at the structural support (i.e., the jacket) for offshore installations for corrosion monitoring, modifications, inspections, etc. The high water current at the intake to the submerged pump poses a safety hazard to divers as they may be pulled into this intake. During the operation of the ill fated Piper Alpha platform it was common practice to switch the fire pump to manual startup mode (requiring an individual... 

Figure 5 shows a cross section of another model size submerged pump. This was successfully tested in liquid hydrogen for about 15 hours. This unit was driven by a Pesco hydraulic motor (shown at the bottom), exterior to the dewar. The hydraulic motor was conveniently used to obtain a variable rpm, in order to determine if the pump obeyed usual affinity laws and other effects of variable speed. 

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