Similarity between P&ID and Electrical diagrams?

In summary, the analogy of fluid flow and electrical current can be helpful to someone with no electronics background, but it can be misleading and engineers and scientists discourage it.
  • #1
Neitrino
137
0
Dear Forum Memebrs,

Could you please advise if it is possible to think that

in some instances the flow of fluid in P&ID diagram is similar to the flow of electrical current in circuit boards: in order to have an electric current you have to have a potential difference across two points (which is called voltage across two point s)thus defining potentials at each junction of complicated electrical circuit one can identify the flow of current, so much the same to have a fluid flow across two points you have to have a pressure differential... Thanks
 
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  • #2
It is true that many people use this analogy. Both fluid pipes and wired circuits conserve energy and mass/charge. But to go beyond that, the analogy can be very misleading, so engineers and scientists discourage it.
 
  • #3
Fluid flow is a useful analogy to initially explain electricity to someone with absolutely no electronics background. Unfortunately, people make a "hobby" out of stretching the analogy too far. It's best to think in terms of ohms law (E=IR) and the inductor (V=Ldi/dt) and capacitor ( I = Cdv/dt) equations and the associated equations for power and energy.

Ohm's law, E=IR, simply says the current through a resistance increases with voltage.

Also, understanding the units is helpful, for example that 1 ampere of current flow is a flow of 1 coulomb/second where a coulomb is a unit of charge equal to 6.241×1018 electrons.

Volts are a bit more complex, representing potential energy per unit of charge or joules/coulomb. In other words, 1 joule of energy change will be imparted to every coulomb of charge passing though two points that have 1 volt of potential difference. You could say that's like a hydraulic pressure drop, but why bother? (to be honest, I seldom think of a volt this way. I just think of it as a volt.)

1 watt is the power dissipated when a coulomb of charge changes by 1 volt every second (or 1 joule per second)

Just reading over those relationships until they feel intuitive (and trying to visualize what is being expressed) is the best way to really get a grasp on electricity.
 

1. What is the main purpose of P&ID and Electrical diagrams?

The main purpose of P&ID (Piping and Instrumentation Diagram) and Electrical diagrams is to provide a visual representation of the process and instrumentation control systems in a facility. P&ID diagrams show the piping and equipment layout, while electrical diagrams show the electrical components and connections.

2. Are there any similarities between P&ID and Electrical diagrams?

Yes, there are several similarities between P&ID and Electrical diagrams. Both types of diagrams use symbols and lines to represent different components and connections. They also both follow a standardized format and layout, making them easy to understand and interpret.

3. How do P&ID and Electrical diagrams differ from each other?

Although P&ID and Electrical diagrams have some similarities, they also have some key differences. P&ID diagrams focus on the process and instrumentation systems, while Electrical diagrams focus on the electrical systems. Additionally, the symbols and lines used in each type of diagram are specific to their respective systems.

4. What is the importance of using P&ID and Electrical diagrams in engineering projects?

P&ID and Electrical diagrams are essential tools in engineering projects as they provide a detailed and accurate representation of the systems in a facility. They help engineers and technicians understand the layout and connections of the systems and can be used for troubleshooting, maintenance, and modifications.

5. Can P&ID and Electrical diagrams be used together?

Yes, P&ID and Electrical diagrams can and often are used together in engineering projects. They complement each other and provide a comprehensive overview of the facility's systems. For example, P&ID diagrams may show the flow of a liquid through pipes, while Electrical diagrams can show the electrical connections of the pumps used to move the liquid.

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