Equipment design, ignorance

Latent failures—conditions present in the system for some time before the incident, but evident only when triggered by unusual states or events. Examples include equipment design deficiencies, unexpected configurations of munitions, or routine ignoring of standard operating procedures. 

It may be preferable to specify the amount of overdesign required for a specific service, rather than specify fouling factors. Aii too often fouiing factors realiy serve as "fudge or "ignorance" factors. A weil-conceived set of criteria for equipment design wiii avoid many problems associated with fouling. 

Belt Presses Belt presses were fiiUy described in the section on filtration. The description here is intended to cover only the parts and designs that apply expression pressure by a mechanism in adchtion to the normal compression obtained from tensioning the belts and pulling them over rollers of smaller and smaller diameters. The tension on the belt produces a squeezing pressure on the filter cake proportional to the diameter of the rollers. Normally, that static pressure is calculated as P = 2T/D, where P is the pressure (psi), T is the tension on the belts (Ib/hnear in), and D is the roller diameter. This calculation results in values about one-half as great as the measured values because it ignores pressure created by drive torque and some other forces [Laros, Advances in Filtration and Separation Technology, 7 (System Approach to Separation and Filtration Process Equipment), pp. 505-510 (1993)]. 

The most conuiion cause of fire accidents in process plants is equipment failure. Tliis is primarily a result of poor equipment maintenance or poor equipment layout and design. Maintenance perfonned according to a detailed and well structured schedule will significantly reduce tlie occurrence of fire accidents. Tlie second largest cause of fire accidents is ignorance of tlie properties of a specific chemical or chemical process. Proper training of employees will increase tlieir knowledge of tlie properties of a specific chemical and chemical process and can prevent many of tliese chemical fire accidents. 

Remember also to take background noise into your calculation. Too frequently, specifications are made which ignore this, with the result that equipment is applied to a more rigid design than is absolutely necessary. 

This is the method of establishing the cost of the plant and equipment over its recognized life cycle. In maintenance situations the design and specification elements may be ignored, but those that must be considered in establishing the life-cycle cost of plant and equipment will include ... 

In this chapter, we consider nonideal flow, as distinct from ideal flow (Chapter 13), of which BMF, PF, and LF are examples. By its nature, nonideal flow cannot be described exactly, but the statistical methods introduced in Chapter 13, particularly for residence time distribution (RTD), provide useful approximations both to characterize the flow and ultimately to help assess the performance of a reactor. We focus on the former here, and defer the latter to Chapter 20. However, even at this stage, it is important to realize that ignorance of the details of nonideal flow and inability to predict accurately its effect on reactor performance are major reasons for having to do physical scale-up (bench —> pilot plant - semi-works -> commercial scale) in the design of a new reactor. This is in contrast to most other types of process equipment. 

In some instances, the number of variables, and hence, the number of subsequent choices are reduced by equipment or user-specified constraints. For example, much of the commercial and home-made equipment is designed to accommodate only pure supercritical fluids or those with a fixed amount of modifier. That is, with some instrumentation the variables of modifier composition and modifier gradient are not convenient to consider. Under such instrument-limited circumstances, those combinations in Table IV that contain either of these variables (X or AX) could simply be ignored, at least on a practical level. Such a constraint would reduce the fifteen 4-variable combinations of Table IV to only one that we will discuss shortly P, T, AP, and AT. 

Factors relating to the safety of a chemical plant have so far been ignored. This is mainly because it is impossible to discuss all the aspects of plant design initially in a set of notes. The designer will obviously design items of equipment, and perform other tasks in process design, in... 

The size and growth of the overall equipment market naturally tempts company strategists into planning entry into the "Electronics Market". For chemical companies this usually means entry at the substrate level. However, what is ignored is that much of the added value occurs in the design and final assembly of the finished black box. PCBs and Hybrids account for only 2.5% of the overall electronics market, and the total value of substrates involved in these two sectors only accounts for some 0.8% of the finished equipment value, and therefore appears to be a very insignificant factor. 

When unsafe factors appear in mechanical equipments, safety supervisors should notice the indications of disturbance or trouble, and handle the problem of machine in time. In designing and using machines , we should not ignore the characteristics and requirements of men, and should not ignore the characteristics and requirements of environment either, so as not to affect the performance of the machine itself, and further not to threat men s lives, work and his survival. If at this time, the safety management system still does not work efficiently, then... 

It is no secret that product designers heavily influence life-cycle costs for their products. The ability to control cost declines sharply once the design has taken shape. However, management processes in many companies ignore this simple fact of life. In the msh to market, they fall short in considering product cost and material availability in advance of introduction. This is especially important in new technology products or products requiring infrastructure investment in the form of new plants and production equipment. 

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