In Need of Your Help Please Ratio Mixing!!

First you put the measurements in similar terms.. liters per minute....

yes I have got that far but as for an equation to calculate the ratio mix I cant find one

So it's 480 to 20 or 24 to 1, and you need 40 to 1....

All you do is multiply each term by the associated ratio (making sure they are in the same unit of measure).

my best suggested ratio is 3 parts OJ: vodka

the fresher the OJ the better, I prefer pulp you may not

If I could afford it, I would throw in half a part of Galliano.

Or for the Galliano, substitute a few drops each of vanilla and anise extract and a sprinkle of ground cloves.

As Solar Eagle stated: reduce the variables to common units, either L/s or L/m.

Personally, you know that you need a maximum (apparently) of 8 L/s of A, and you know the flow of B is 1/40 of that, namely 8/40 = 0.20 L/s. To set the batch controller, have it derive the flow for B, based upon the observed flow for A.

0.20 L/s = 12.0 L/m (convert from seconds to the amount in 60 seconds).

Thus, the entire ratio factor is A*60/40 or 1.5 A (L/s) = B L/m

in other words, whatever the flow is on the A tube, the B tube reading is multiplied by 1.5 to get the proper dosing.

There is a $200.00 surcharge for college student homework in here. Just kidding.

I get 40/24 = 1.66

How in the H E double sticks does 24 come into this between L/s and L/m?

You know the answer is 42. You just need a plausible question.

but I hate when that evil 42 keeps popping up!

But it has the magic numbers: 2, 3 and 7, all magical and theologically rich prime numbers.

3? 42/2/3 = 7, etc.?

Yup, you obviously need to sign up for useful classes like Numerology 101 and Astrology 103.

Step 1 Multiply the full scale reading of sensor A by 60 to get the same units on both sensors 40x60=480

Step 2 Both at full scale the the sensors would deliver a ratio of 480:20

Step 3 Divide both sides by 12 so that sensor A has the 40 of the 40:1 desired ratio 480/12:20/12 = 40:20/12 or 40:5/3. at full scale reading

Step 4 Multiplying sensor B by it's inverse (3/5) gives you a value of 1 5/3x3/5 =1 3/5 is 60% or 0.6

By turning down the full scale reading on sensor B to 60% you get the correct ratio. So you set Sensor A to 100% and sensor B to 60% on the DCS controller

OK Brent, I have shown you how to get the answer, but if I was marking the question I would only award 4 marks. Now you tell me why I lost two marks for the correct working and the correct settings on the DCS.