P ID symbols

P ID Symbols and Legends WRS Sump Pump Bearing Cooling Wtr WRS... 

Many chemical and petroleum companies are now using Process Industry Practices (PIP) criteria for the development of P IDs. These criteria include symbols and nomenclature for typical equipment, instrumentation, and piping. They are compatible with industry codes of the American National Standards Institute (ANSI), American Society of Mechanical Engineers (ASME), Instrument Society of America (ISA), and Tubular Exchanger Manufacturers Association (TEMA). The PIP criteria can be applied irrespective of whatever Computer Assisted Design (CAD) system is used to develop P IDs. Process Industries Practice (1998) may be obtained from the Construction Industry Institute mentioned in the References. 

They should be consistent. Generally, consistency is achieved by using the first P ID in a series—the Legend Sheet— to define the symbols and conventions used on this particular process (such as line labeling conventions). 

The nomenclature used for instrumentation is more complex than for equipment and process lines. Walker (2009) provides a list of commonly used instrument symbols. Typically an instrument balloon on a P ID contains two or three letters followed by five digits. So PI-30012, for example, identifies a pressure indicator number 12 in Section 30. 

Instrumentation symbols are shown on a P ID as a circle, inside which information is included that tells the process technician what type of instrument is represented. Figure 7-17 shows examples of typical instrument symbols. 

Electrical drawings include symbols and diagrams that depict an electrical process system. Electrical drawings show unit electricians where power transmission lines run and places where it is stepped down or up for operational purposes. A complex P ID is designed to be used by a variety of crafts. The primary users of the document after plant start-up are process technicians, instrument and electrical, mechanical, safety, and engineering. 

In the P IDs the design descriptions and their corresponding symbols have to be inserted. It has also to be emphasized that all components and aggregates of the designed plant must be included in the P IDs. The demand for such completeness results, inter alia, from the fact that the P IDs are the basis for the compilation of lists and that the P IDs are used for the later test on completion at the end of the assembly (see section 4.9, Erection ). 

All process information that can be measured in the plant is shown on the P ID by circular flags. This includes the information to be recorded and used in process control loops. The circular flags on the diagram indicate where the information is obtained in the process and identify the measurements taken and how the information is dealt with. Table 1.10 summarizes the conventions used to identify information related to instrumentation and control. Exanple 1.9 illustrates the interpretation of instrumentation and control symbols. 

In order for flowsheets and P IDs to be understood by people with different job responsibilities such as plant designers, process engineers, instrumentation specialists, and vendors, it is useful to use standardized symbols and conventions on the flowsheets. Standards concerning instrumentation symbols and flowsheet conventions have been developed by technical societies, such as the International Society of Automation (ISA). However, individual companies often use different or additional symbols for particular processes. 

Figure 8. Three-dimensional mean-potential surface for the X IT state of HCCS, (Pi, Pa, y), presented in form of its ID sections. Curves represent the function given by Eq. (75). (with Ati — 0.0414, k2 — 0.952, tt 2 — 0.0184) for fixed values of coordinates p, and P2 (attached at each curve) and variable y — 4 2 4t Here y — 0 corresponds to cis-planar geometry and Y = ft to trans-planar geometry. Symbols results of explicit ab initio computations.

As illustrated in this ehapter a p2 eonfiguration (two equivalent p eleetrons) gives rise to the term symbols 2p, iD, and S. Coupling an additional eleetron (3d to this p2... 

The term symbols are G, 3p, Id, - P, and S. The L and S angular momenta can be vector coupled to produce further splitting into levels ... 

Refs. [i] Mills I, Cvitas T, HomannK, KallayN, Kuchitsu K (eds) (1993) IUPAC quantities, units and symbols in physical chemistry. Blackwell Scientific Publications, Oxford, p 71 [ii] Quack M, Frey J (2005) IUPAC quantities, units and symbols in physical chemistry, 3rd edn. Pure Appl Chem Manuscript ID PAC-REC-05-11-10 [iii] Cardarelli F (1997) Scientific unit conversion. A practical guide to metrication. Springer, London... 

Bold type indicates a stressed syllable. In pronunciations, a consonant is sometimes doubled to prevent accidental mispronunciation of a syllable resembling a familiar word for example, /ass-id/ (acid), rather than /as-id/ and /ul-tra- sonn-iks/ (idtrasonies), rather than /ul-tra-son-iks/. An apostrophe is used (a) between two consonants forming a syllable, as in /den-t l/ (dental), and (b) between two letters when the syllable might otherwise be mispronounced through resembling a familiar word, as in /th e-ra-p>ee/ (therapy) and /tal k/ (talc). The symbols used are ... 

The set made by the three p-type functions in a Gaussian type orbital (GTO) framework is sufQciently simple to be used as an example but at the same time provides a yet unexplored context, which can show how QS techniques can handle quantum system states, even degenerate ones. The set of p-type Gaussian functions can be collected into a vector, which can be associated in turn to three degenerate model wavefunctions Ip) = qr exp(-alrP) where q is a normalization factor, r = (x,y,z), and a is an arbitrary positive-definite parameter. The set of attached DF can be also written as a vector Id) = q (r r) exp (-2alrP), where the position vector product symbol is defined employing the inward product (r r) = Thus, the components... 

---