How much time to design ?

[kurtz]

How much time do You usually have to design:
-simple pressure vessel (about 10 nozzles)
-simple heat exchanger ((about 10 nozzles)
calculations + drawings

Two weeks, three weeks or more?

 

[pmover]

what is simple?
process data will largely dictate the design duration, along with codes, specifications, and other project specific requirements.
a 665-psig, 120-F, 3-phase separator took 6 months from RFP to complete the design.

more data will provide a better response.

 

[marty007]

If our engineering department is quiet (not bogged down with many other vessels), we have all of the necessary information, and it is a truly simple piece of equipment, we can normally complete calculations and drawings in as quickly as:
[ul]
[li]Simple pressure vessel: 3-4 days[/li]
[li]Simple heat exchanger: 1 week[/li]
[/ul]

That said, it's very rare that this is the case. Often information is missing, a request is made for some unusual design feature, or the order comes in alongside 5 or more other pressure vessels. In which case, similar to pmover's experience, this can extend out to 2-weeks, 4-weeks, ..., 6-months.

It often amazes me how purchase orders are sometimes placed when the buyer has so little information available. What are they buying?! Then I spend over a month dragging the information out of the customer before I can complete the design.

 

[JStephen]

Two other major factors- the degree of software support available, and the amount of previous experience with similar items.
So, a simple vessel per your note, maybe a week for one person, assuming design is per vessel software, drawing is by AutoCAD, and that previous details are available to cut-n-paste.
If you had to work through the design by hand, and then drew the first vessel like that you ever drew, then more like 3-4 weeks.
If you're also learning the code as you go along, even longer.
In real life it's "Do this ASAP! But first, do this other thing...And this other thing...oh, here's a hot item, fit it in front of there..."

 

[marty007]

In real life it's "Do this ASAP! But first, do this other thing...And this other thing...oh, here's a hot item, fit it in front of there..."

Couldn't have said it better!

That's when I call a meeting with the sales team, lay in front of them all of the to-do items that have been thrown on my desk in the last week, and ask them to set priorities. Then I sit back and watch the fireworks.

 

[viper3982]

Assuming you had just ONE project to work on: anywhere between 1 day and 1 year.

What are the design considerations: is it a Code vessel? What code? ASME, PED, MOM?
What is a 'simple pressure vessel'?
Are you worried about just ASME calcs? Does the customer want wind/seismic FEA? What if they ask for environmental impact analysis?
What if they want it painted with a paint / rust preventative that's illegal to use in the country of manufacture?

The point being: A 'simple pressure vessel' to one person (sales team) might not be the same thing to the engineer.

What happens when you spend a month trying to get it to submit to the broken web-portal that they REQUIRE you to interface with....then they take 2 months to get back with customer approval on comments that they demand you resolve instantly?

It almost sounds like a question that a sales manager would ask on this form to try and paint his engineering team as lazy/taking too much time.
"Well, OTHER engineering teams could do it in X days..."

Be careful when answering questions like this to sales/project managers...they tend to have amnesia about all the details and only worry about the time quoted BEFORE they give you all the customer specifications.

Don't forget JStephen's comment: ...do this as your #1 priority...but this OTHER project should be a higher #1 priority...

 

[SnTMan]

As others have said, it can vary greatly, but, for a TEMA type shell & tube exchanger:

1) Read contract, perform mechanical calculations, prepare ACAD layout & Outline drawing:
Low End: 16 hrs, High End: 40 hrs

2) Make & check shop drawings
Low End: 40 hrs, High End: 120 hrs.

3) Address customer and internal questions, conference calls, NCR's & general crisis management:
Low End: 10 hrs, High End: Sky's the limit

Regards,

Mike


The problem with sloppy work is that the supply FAR EXCEEDS the demand