Hydraulic couplings

Any material used to prevent fluid leakage in joints, flexible couplings, hydraulic glands, etc. 

Cai J and Wu Y. 2001. Analysis of one-dimensional seepage model by coupling hydraulic head gradient, temperature gradient and stress. Chinese J. Rock Mech. Engng., 20(suppl), pp. 1026-1028. 

To investigate the behaviour observed in both the Isothermal Test and Buffer Container Experiment numerical simulations have been undertaken. In particular coupled hydraulic-mechanical analyses of the Isothermal test and thermal-hydraulic-mechanical analyses of the Buffer Container Experiment have been undertaken. These analyses have been performed via a finite element computer code, COMPASS (Thomas and He, 1997 1998). 

Biot (1941) derived the 3-D consolidation theory, which describes the coupled hydraulic and mechanical transient response of a linear elastic, isotropic, homogeneous porous medium. One aspect of his theory is the effective stress law for elastic deformation ... 

Consider the coupled hydraulic tanks depicted in Fig. 4.7. The nonlinear characteristic of the valves is given by Bernoulli s well-known square root law. It is assumed that the constitutive equations of the valves have been linearised around an operating point so that the model equations are linear and Laplace transform can be applied. 

Pig. 4.8 Bond graph of the coupled hydraulic tank system... 

Consider the simple linear electrical network depicted in Fig. 4.19. It can be viewed as an electrical analogue of the coupled hydraulic tank system considered in Section 4.4.1. A bond graph of the direct model with the two inputs I(t) and E(t) and the two outputs e and /2 appears in Fig. 4.20. There is one set of two disjoint input-output causal paths... 

For instance, power can be transmitted from one machine to the other through shafts, flexible couplings, and gear reducers (mechanical equipment). Power can be transmitted through a torque converter (hydraulic equipment) or by a combination of mechanical and hydraulic equipment. 

Why do we use the word driver We tend to think that pumps are powered by r-r motors. However, some pumps are powered by internal combustion engines, or with turbines or hydraulic motors. Not always are pumps and drivers connected h a direct coupling. Some pumps are coupled through pulleys, chain drives, gearboxes or even transmissions. 

Figure 6-33. The coupling hole alignment tool (CHAT) has a longitudinally split sleeve for greater expansion. Like the radial fit bolt, it is hydraulically tensioned, but there is no hydraulic separation of core and sleeve.

Use a close coupled ell for drawoff from gravity separators to eliminate backup of hydraulic head. 

Each shaft should have an integral coupling flange rather than a removable coupling hub. If removable hubs must be used for some rea son, they should be of the keyless, hydraulically dilated design,... 

In January 1903 Einstein married Mileva Marie, (of Grcck-Catholic Serbian descent), a fellow student at the ETI I. In 1902 the couple had a daughter out of wedlock, Lieserl, whose fate remains unknown, and after marriage they had two sons, Hans Albert (1904), who became a distinguished professor of hydraulic engineering in Berkeley, California, and Eduard (1910), a gifted child who became a student of medicine in Zurich but who then turned severely schizophrenic and died in a psychiatric hospital. 

The most common quick-disconnect coupling for hydraulic systems consists of two parts, held together by a... 

With the trend toward higher pressures in hydraulic systems, the loads on unbalanced pump and motor components become greater and this, coupled with the need for closer fits to contain the higher pressures, can introduce acute lubrication problems. Pumps, one of the main centers of wear, can be made smaller if they can run at higher speeds or higher pressures, but this is only possible with adequate lubrication. For this reason, a fluid with good lubrication properties is used so that hydraulics is now almost synonymous with oil hydraulics in general industrial applications. Mineral oils are inexpensive and readily obtainable while their viscosity can be matched to a particular job. 

The use of hydraulic systems for the setting, operation and control of machine tools has increased significantly. Hydraulic mechanisms being inter-linked with electronic controls and/or feedback control systems. In machine tools, hydraulic systems have the advantage of providing stepless and vibration-less transfer of power. They are particularly suitable for the linear movement of tables and slideways, to which a hydraulic piston may be directly coupled. 

The sections to follow provide overviews of the more common coupling types rigid and flexible. Also discussed are couplings used for special applications floating-shaft (spacer) and fluid (hydraulic). 

Two special application couplings are discussed in this section (1) floating-shaft or spacer coupling and (2) hydraulic or fluid coupling. 

One particular characteristic of conduction heat transfer in micro-channel heat sinks is the strong three-dimensional character of the phenomenon. The smaller the hydraulic diameter, the more important the coupling between wall and bulk fluid temperatures, because the heat transfer coefficient becomes high. Even though the thermal wall boundary conditions at the inlet and outlet of the solid wall are adiabatic, for small Reynolds numbers the heat flux can become strongly non-uniform most of the flux is transferred to the fluid at the entrance of the micro-channel. Maranzana et al. (2004) analyzed this type of problem and proposed the model of channel flow heat transfer between parallel plates. The geometry shown in Fig. 4.15 corresponds to a flow between parallel plates, the uniform heat flux is imposed on the upper face of block 1 the lower face of block 0 and the side faces of both blocks... 

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