I am attempting to explain to my boss the dependency of gas composition to the transit time in ultrasonic meters. I am getting conflicting information of the dependency of the speed of sound in a gas with molecular weight. Some (reputable?) web sites show an equation with dependency on...
We are flowing water into a basin that is 150 psig upstream. The outlet is above the basin. The design now is to use a restriction orifice to create enough backpressure to prevent flashing & cavitation. The new idea is to submerge the outlet deep enough into the basin such that the pressure at...
We are installing an RO to let down the pressure downstream of a control valve. Since we are only taking a pressure drop and not taking flow measurements, is it necessary to have straight run requirements?
I have a situation where where water will flash through a globe valve to an an open basin downstream. There will be some piping downstream of the valve before emptying into the basin. What (if any) are the issues I need to consider with regards to the downstream piping arrangement?
This is related to a real world design issue. If you have a process where the pressure of a compressible fluid is being measured downstream and a sudden change in pressure occurs (e.g. step change), how do you determine the time of propagation between the the point of change and the point of...
I have a process variable input consisting on a pressure transmitter followed in series by two signal conditioners. I am given the response time of the transmitter and the corner frequencies of the signal conditioners (acting essentially as low pass filters). I guess that for each signal...
In general terms, could someone please explain the effect that a low pass filter on the input of a PID controller would have on the response of the system? The controller will compare the process variable against a setpoint, but for reasons I'll not get into here, the process variable first...
We are measuring Natural Gas Flow using a meter run where where we are expecting 99.84% vapor mass fraction and the remainder is NG liquids (P = 1100 psig). Yes the vapor fraction is very high, but it is still two phase flow. Will the flow calculations for pure vapor still apply? Any other...
I am looking for some "rules of thumb" for sizing an air compressor that will service several valves (control & shutdown). Obviously we could go into a detailed analysis of actuator sizing, air consumption, cycle time, etc. But this is an estimate. We have estimates of the number of valves &...
I am sizing a Fisher regulator for air and I have calculated the Cv required . The product data sheet(s) however give me "wide open flow" and C1. I understand the definition of C1 but but how does this relate to my calculation? Is my criteria that I nedd to be below the wide open flow...
What is the difference between the Cv and Cg (gas sizing coefficient) for a regulator? It seems like sizing regulators differs from sizing control valves in this respect.
I am sizing regulators (Fisher, specifically) Their technical bulletins give guidance such as IEC constants for sizing just as you would any other valve, but they also provide data for calculating "wide open flow for relief valve calculations". I do not know what this means. Is this the...
While looking at photographs of a chemical plant, I had noticed that in several places the piping takes a right angle jog, turns back to the original direction, then takes two more turns to be back in line with the pipe. On the photos these were referred to as "loops." What is the purpose? It...
We are investigating the use of ultrasonic techniques to achieve atomization/evaporation of Hydrogen Peroxide in aqueous solution. Anyone have experience in this technique or that can recommend where to start?
We are investigating the use of ultrasonic to vaporize an aqueous solution of Hydrogen Peroxide. Anyone out there that has seen this done for any substances? We would like to understand the process better.
I am looking for resources to help me to determine the time to heat up air circulating in a closed loop by passing it through a fin & tube exchanger where the heating medium is a glycol loop that is picking up waste heat from a generator. Both the air and glycol start out at the same...
I am looking for all the resources I can gather on how to design a manifold that will evenly distribute flow (air in my case but for any fluid in general) from a header pipe to several branch lines. Perry's devotes about 2 pages to the design of a perforated distributor. It's useful...
