Ejectors Have a Wide Range of Uses
作者/来源:F. DUNCAN BERKELEY 日期:2010-11-16 点击量:716
Ejectors are employed in the industry in numerous, unique and even sometimes bizarre ways. They can be used singly or in stages to create a wide range of vacuum conditions, or they can be operated as transfer and mixing pumps. The ejectors have the following advantages over other kinds of pumps:
• Rugged and simple construction
• Capability of handling enormous volumes of gases in relatively small sizes of equipment
• Less maintenance requirements
• Simple operation
WHAT MAKES THEM WORK
All ejectors operate on a common principle. The single stage ejector, in its simplest form, consists of an actuating nozzle, suction chamber and a diffuser. The actuating fluid, which may be a gas, vapor or liquid, is expanded from its initial pressure to a pressure equal to that of the secondary fluid. In the process of being expanded, the actuating fluid is accelerated from its initial entrance velocity, which is negligibly small, to a high velocity. In the suction chamber, the actuating fluid induces a region of low pressure-high velocity flow which causes the secondary fluid to become entrained and mixed with the actuating fluid. During the mixing process, the actuating fluid is retarded and the secondary fluid is accelerated. As the mixture enters the diffuser, it is compressed to the exit pressure by rapid deceleration. The purpose of the ejector is to transport and compress a weight of induced fluid from the suction pressure to the exit pressure. By staging ejectors it is possible to obtain a very large range of suction pressures from atmospheric down to as low as one micron of mercury absolute.
For details.....
• Rugged and simple construction
• Capability of handling enormous volumes of gases in relatively small sizes of equipment
• Less maintenance requirements
• Simple operation
WHAT MAKES THEM WORK
All ejectors operate on a common principle. The single stage ejector, in its simplest form, consists of an actuating nozzle, suction chamber and a diffuser. The actuating fluid, which may be a gas, vapor or liquid, is expanded from its initial pressure to a pressure equal to that of the secondary fluid. In the process of being expanded, the actuating fluid is accelerated from its initial entrance velocity, which is negligibly small, to a high velocity. In the suction chamber, the actuating fluid induces a region of low pressure-high velocity flow which causes the secondary fluid to become entrained and mixed with the actuating fluid. During the mixing process, the actuating fluid is retarded and the secondary fluid is accelerated. As the mixture enters the diffuser, it is compressed to the exit pressure by rapid deceleration. The purpose of the ejector is to transport and compress a weight of induced fluid from the suction pressure to the exit pressure. By staging ejectors it is possible to obtain a very large range of suction pressures from atmospheric down to as low as one micron of mercury absolute.
For details.....