Squeezing out

In rare cases compaction may be artificially Initiated by the withdrawal of oil, gas or water from the reservoir. The pressure exerted by the overburden may actually help production by squeezing out the hydrocarbons. This process is known as compaction drive and some shallow accumulations in Venezuela are produced In this manner in combination with EOR schemes like steam injection. 

Processes. The most common method for the appHcation of chemicals to the surface of a paper web is by a size press. In the size press, dry paper, which usually is sized to prevent excess water and chemical penetration, is passed through a flooded nip or pond, and a solution or dispersion of the functional chemical contacts both sides of the paper. Excess Hquid is squeezed out in a press and the paper is redried. 

Dryers. A drying operation (see Drying agents) needs to be viewed as both a separation and a heat-exchange step. When it is seen as a separation, the obvious perspective is to cut down the required work. This is accompHshed by mechanically squeezing out the water. The objective is to cut the moisture in the feed to the thermal operation to less than 10%. In terms of hardware, this requires centrifuges and filters, and may involve mechanical expression or a compressed air blow. In terms of process, it means big crystals. 

A belt filter press consists of a gravity drainage belt, foUowed by a series of roUer presses which squeeze out water. 

The next stage may best be described as a primitive hot-filtration process. Two members of the village sit across the front of a simple fire resembling a Dutch oven, holding between them a bag about 30 feet long and about two inches in diameter. The lac inside the bag melts and, through one of the operators twisting the end of the bag, the lac is squeezed out. The lac is then removed from the outside of the bag and collected into a molten lump which is then stretched out... 

Inspection. After the final adhesive cure cycle, the bonded assembly is removed from the tool and inspected. The first and most cursory inspection is a simple visual check. Major problems such as crushed core and significantly mis-located details can be seen with the unaided eye. A lack of continuous adhesive squeeze-out ( flash or spew ) around the periphery of details can be indicative of insufficient adhesive and subsequent voids. 

Compression moulding is one of the most common methods used to produce articles from thermosetting plastics. The process can also be used for thermoplastics but this is less conunon - the most familiar example is the production of LP records. The moulding operation as used for thermosets is illustrated in Fig. 4.62. A pre-weighed charge of partially polymerised thermoset is placed in the lower half of a heated mould and the upper half is then forced down. This causes the material to be squeezed out to take the shape of the mould. The application of the heat and pressure accelerates the polymerisation of the... 

Variations on this basic process are (i) vacuum bag moulding and (ii) pressure bag moulding. In the former process a flexible bag (frequently rubber) is clamped over the lay-up in the mould and a vacuum is applied between the moulding and the bag. This sucks the bag on to the moulding to consolidate the layers of reinforcement and resin. It also squeezes out trapped air and excess resin. The latter process is similar in principle except that pressure is applied above the bag instead of a vacuum below it. The techniques are illustrated in Fig. 4.67(b) and (c). 

At high speeds, however, a position can be reached in which the load-carrying capacity increases with speed. The explanation is thought to be that when the teeth are in contact for such a short time, the oil film is not squeezed out and a separating film is therefore maintained. 

The lubrication of leadscrews is similar in essence to that of slideways, but in some instances may be more critical. This is especially so when pre-load is applied to eliminate play and improve machining accuracy, since it tends to squeeze out the lubricant. Leadscrews and slideways often utilize the same lubricants. If the screw is to operate under high unit stresses - due to pre-load or actual working loads - extreme-pressure oil should be used. 

Spray-up Popular system with reinforced plastic production. An air spray gun includes a roller cutter that chops usually glass fiber rovings to a controlled short length before being blown in a random pattern (manually or automatically) onto a surface of the mold simultaneously the gun sprays catalyzed TS polyester plastic. The chopped fibers are plastic coated as they exit the gun s nozzle. The resulting, rather fluffy, RP mass is consolidated with serrated rollers to squeeze out air and reduce or eliminate voids. A closed mold... 

B. Immediately wipe the eye using pressure to squeeze out excess medication. 

Toothpaste must have thickeners to help it squeeze out of the tube and stay on the toothbrush. It must have detergents to remove fatty films, water softeners to make the detergents work better, and sweeteners (preferably non-nutritive so as not encourage bacteria). 

Figures 8.5 and 8.6. The liquid is carried round in the spaces between consecutive gear teeth and the outer casing of the pump, and the seal between the high and low pressure sides of the pump is formed as the gears come into mesh and the elements of fluid are squeezed out. Gear pumps are extensively used for both high-viscosity Newtonian liquids and non-Newtonian fluids. The lobe-pump (Figures 8.7 and 8.8) is similar, but the gear...

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