Download (direct link):
FIG. A-27 Predicted sound reduction indices of two high-performance panels. (Source: Altair Filters International Limited.)
In summary. The acoustic performance of corrugated and flat steel panels can be predicted. The acoustic behavior of corrugated panels is very different from that of flat panels. This means that if corrugated panels are required, careful consideration must be given to the design, since unlined corrugated panels are unsuitable on their own for noise control applications.
However, the greater bending stiffness of corrugated panels offers many financial and structural advantages in the demanding environment that exists offshore, especially for gas turbines.
By lining the interior of a corrugated panel with a material whose physical parameters have been carefully chosen, the inherent acoustic weaknesses can be overcome. Thus a more cost-effective approach to gas turbine enclosure design can be adopted, which considers the structural integrity, weight, cost, ease of manufacture, and acoustic performance. The resultant designs employ less bracing and thinner outer skins to achieve the same acoustic performance as flat-walled constructions weighing typically 25 percent more than the equivalent corrugated design.
Electrohydraulic actuators are among the more common varieties of actuators in the process plant market and are also more accurate in terms of position control. These components have very specific (to a particular manufacturer) design components. Therefore, terminology in the detailed descriptions that follow is specific to the information source, J.M. Voith GmbH in this case. In the case of requesting competitive bids, the end user should consider requesting similar or alternate features.
A-38 Aerfoils; Airfoils
Areas of Applications Benefits*
¦ Reliable and highly accurate conversion of electrical control signals into specific process values.
¦ Combination of electronics, sensor technology, and mechanics resulting in reduction of interfaces and high degree of reliability.
¦ High regulated magnetic forces (use of Hall effect) make it possible to apply robust magnetic drives.
¦ No need for external regulating equipment since complete regulating system is integrated in the chassis of the control unit for the magnetic drive (high degree of EMV resistance).
¦ Parameters for controller output range can be set from outside.
¦ High degree of reliability.
¦ Infinitely variable conversion of input signal iE into output modes power, pressure, or stroke with high dynamic force.
¦ Inversion range E < 0.05%.
¦ Conversion time for 50% regulating value 25 msec.
¦ Integrated sensor technology and control electronics with function monitoring and actual value remote display output in robust housing or in pressure-resistant casing.
¦ Electrohydraulic alternative to the retrofitting and modernization of mechanical/hydraulic control and regulatory systems.
Figures A-28 to A-37 and their descriptions outline a typical comprehensive range
of electrohydraulic actuators. Different designs may be designated with a specific
trademark. This is indicated where relevant.
Aerfoils; Airfoils (see Metallurgy; Turbines) Agitators
Broadly speaking, agitators can be used to produce the following:
1. Uniformity between different components, solid or liquid, miscible, or otherwise. This produces liquid blends or solid suspensions (see Gravity Blending in the section on Tanks).
2. Heat or mass transfer between matter. Applications include extraction and leaching processes (see Oil Sands).
3. Phase changes in a mixture. Homogenizing, emulsification, and crystallization are among these processes (see Centrifuges).
Reference and Additional Reading
1. Bloch, H., and Soares, C. M., Process Plant Machinery, 2d ed., Butterworth-Heinemann, 1998.
* Source: J.M. Voith GmbH, Germany. Adapted with permission.
Power station applications:
Controlling the power output of gas and steam turbines.
Controlling process demands steam pressure and grid power.
Chemical and petrochemical plants:
Controlling energy and mass flows.
Food processing plants: Controlling energy flows.
FIG. A-28 Applications of hydraulic actuators by industry and control function. (Source: J.M. Voith GmbH.)