Unwanted heat is a problem for all hydraulic systems. Even a well-designed system operating at top efficiency converts about 20% of its input power to heat. An inefficient system, or one poorly matched to its task, may convert nearly 100% of input power to heat at certain times in the cycle. The heat input can be dissipated through natural cooling; if this is insufficient, a heat exchanger is added to the system. draw heat from the hydraulic fluid and transmit it into a cooling fluid, usually water. Most liquid-to-liquid exchangers use a shell-and-tube package, consisting of a bundle of small tubes inserted into a shell. The coolant flows through the small tubes, and the hydraulic fluid passes around and between the tubes. These units are compact, reliable, and are often less expensive to install and maintain than other types. There are two basic types of shell-and-tube exchangers: the U-tube (or hairpin) type and the straight-tube type. Either type can have either a fixed or removable tube bundle. Removable bundles can be withdrawn from the shell as an assembly for maintenance, but fixed bundles must remain in the shell. A normal rule of thumb is that U-tube exchangers are best suited for high-temperature, high-pressure applications, with the straight-tube units most thermally efficient and least expensive. Liquid-to-liquid exchangers are available in single or multiple-pass, parallel, or reverse-flow arrangements. The multiple-pass, reverse-flow units provide the greatest heat transfer for a given size. Standard liquid-to-liquid units have a working pressure of 150 psi and can handle temperatures to 300°F, although the actual temperature difference between oil and water should not exceed 200°F. Special units are available to operate at pressures to 300 psi. transfer heat from hydraulic fluid to ambient air. Working much like an automobile radiator, they allow air to be passed over finned
Products & Services
Heat exchangers are commonly used in a wide variety of industrial, chemical, and electronics processes to transfer energy and provide required heating or cooling.
Economizers are mechanical devices that are designed to reduce energy consumption, or to perform other useful, energy-related functions (such as preheating fluids).
Vaporizers are heat exchangers that convert liquefied gases to a warm gaseous product. The heat source can be ambient air, steam or water.
Condensers are devices which accept a vapor stream and convert it to a liquid using heat transfer and/or compression.They are used in steam turbines for power plants, in cooling units for in-process fluids, and in air conditioning systems for buildings and automobiles.
X-ray sources are lamps that generate or produce X-rays, a form of electromagnetic radiation, for non-destructive testing (NDT) or inspection.
Topics of Interest
Shell and tube (tubular) heat exchangers are used in applications where the demands from high temperatures and pressures are significant. Tubular heat exchangers are also used with fluids that contain...
Chapter 1: Heat Conduction
Figure 1.1: One-dimensional heat conduction in a solid
Figure 1.2: Differential volume element used in derivation of conduction equation
Figure 1.3: Heat...
Chapter 1: Heat Conduction
Table 1.1: The Heat Conduction Equation
Table 1.2: Expressions for Thermal Resistance
Table 1.3: Conduction Shape Factors (Source: Ref. )
Table 1.4: The...
A reboiler is a heat exchanger that is used to generate the vapor supplied to the bottom tray of a distillation column. The liquid from the bottom of the column is partially...
shell- or tube-side fluid viscosity, cP
fluid viscosity at system temperature, cP 2.42