Cylindrical presses

In the press process, the seed from which oil is to be removed is cracked and crushed to produce flakes about 0.25 mm thick, which are cooked at temperatures up to 104 °C for 15-20 minutes. The temperature is then raised to about 110-115 °C until the moisture content is reduced to about 30 g/kg. The material is then passed through a perforated horizontal cylinder in which revolves a screw of variable pitch that gives pressures up to 40 MN/m. The residue from screw pressing usually has an oil content of 25-40 g/kg. The cylindrical presses used for extraction are called expellers and the method of extraction is usually referred to as the expeller process. 

An indatable diaphragm or membrane has been used in membrane plate presses closely related to the conventional plate and frame presses. A pressure filtration period is foUowed by compression with the hydraulically operated membrane or by a hydraulically operated ram if dexible rim seals are fitted. This principle also is used in vertical presses that use either one or two endless cloth belts indexing between plates. Indatable membrane also may be used on a cylindrical filtration surface with or without a preceding pressure filtration stage. 

Cylindrica.1 Presses. Another group of filters that utili2e the variable chamber principle are those with a cylindrical filter surface. There are two designs in this category, both of which originate from the United Kingdom. 

Lower cost and lower weight cylindrical cells have been made using plastic bound or pasted actwe material pressed into a metal screen. Tliese cells suffer slightly in utilization at high rates compared to a sintered-plate cylindrical cell, but they may be adequate for most applications. Tlie effect of temperature and discharge rate on the capacity of sealed nickel-cadmium cells is illustrated in Figure 8 and Table 3. 

Eor irregular or spherical bodies, a cylindrical container is loaded with a 100 gram or larger sample and a pistonlike cover is placed on top of the sample. The container is placed in a hydraulic press and a predeterrnined amount of force is appHed to the cover at a controUed rate. The sample is removed from the container and screened to remove cmshed particles (fines). The bulk cmsh strength is reported in terms of percent fines generated by a specified force. 

Gas Holders Gas is sometimes stored in expandable gas holders of either the hquid-seal or dry-seal type. The hquid-seal holder is a familiar sight. It has a cylindrical container, closed at the top, and varies its volume by moving it up and down in an annular water-filled seal tank. The seal tank may be staged in several lifts (as many as five). Seal tanks have been built in sizes up to 280,000 m (10 X lO fE). The dry-seal holder has a rigid top attached to the sidewalls by a flexible fabric diaphragm which permits it to move up and down. It does not involve the weight and foundation costs or the hquid-seal holder. Additional information on gas holders can be found in Gas Engineers Handbook, Industrial Press, New York, 1966. 

The suction gas which enters from the periphery is trapped by the scrolls. The closed volumes move radially inward until the discharge port is reached, when vapor is pressed out. The orbiting scroll is driven by a short-throw crank mechanism. Similar to screw compressors, internal leakage should be kept low, and is occurring in gaps between cylindrical surfaces and between the tips of the involute and the opposing scroll base plate. 

Ur, Ur, and u- are the cartesian results Ur and u- are the results in cylindrical co-ordinates. Note u is in the direction of positive P, pressing into the half plane for compressive loading. The tangential displacements of the free surface are towards the origin in agreement with our intuition. 

API Filtration. A filter press is used to determine the wall building characteristics of mud. The press consists of a cylindrical mud chamber made of materials resistant to strongly alkaline solutions. A filler paper is placed on the bottom of the chamber just above a suitable support. The filtration area is 7.1 ( 0.1) in.-. Below the support is a drain tube for discharging the filtrate into a graduate cylinder. The entire assembly is supported by a stand so that a 100-psi pressure can be applied to the mud sample in the chamber. At the end of the 30-min filtration time volume of filtrate is reported as API filtration in milliliters. To obtain correlative results, one thickness of the proper 9-cm filter paper, Whatman No. 50, S S No. 5765, or the equivalent, must be used. 

Cylindrical batteries can be classified into two basic types one with a spiral structure, and one with an inside-out structure. The former consists of a thin, wound cathode and the lithium anode with a separator between them. The latter is constructed by pressing the cathode mixture into a high-density cylindrical form. Batteries with the spiral construction are suitable for high-rate drain, and those with the inside-out construction are suitable for high energy density. 

Tewarson, A., and Khan, M.M., "Flame Propagation for Polymers in Cylindrical Configuration and Vertical Orientation," Twenty-Second International Symposium on Combustion, The Combustion Institute, Pittsburgh, PA, (In press). 

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