Air Consumption Rate of Cylinder Actuators on SKG200 Valves

[WillemBouwer]

Hi all

I am trying to set up a report showing the air consumption rate of my cylinder actuators on different valves. I am stuck at the very end where I should calculate the air consumption rate. All calcs are in metric units.

Okay as an example let's use the following:
Valve: SKG200 with closing thrust 1259kg at 10bar line pressure.
Actuator size: D = 250 mm
Valve stroke: S = 296 mm
Cylinder rod diameter: d = 32 mm
Available air pressure: P2_gauge = 4 bar

Now I calculated the total cylinder volume for the closing and opening strokes:
V_open = ((D-d)/10)^2*∏/4*S = 8584.8 cm^3
V_close = (D/10)^2*∏/4*S = 11290.1 cm^3

So the total air consumption respectively:
Air_open = V_open*(P2_guage+1)/1000 = 42.92 liter
Air_closed = V_close*(P2_guage+1)/1000 = 56.5 liter

And with a maximum operating speed of 25mm/s we calculate that the duration of the stroke is:
t = S/25 = 296/25 = 11.84 sec

So now that I have all this info, how do I calculate the rate of air consumption if I want to know what size compressor to buy... Thanks guys and I hope this is in the correct forum...

 

[CWatters]

Are you saying:

a) it uses 43L to move the piston one way and another 57L to move it back the other way? eg a total of 100L per cycle?

or

b) The cylinder volume changes from 43 to 57 L in one stroke and no air is used for the return stroke? (eg the load or a spring does the return).

Is the duration of the stroke the same in both directions? eg The cycle time is 2 * 11.84 = 23.68 seconds?Assuming you mean a) then..

The max consumption is going to be around...

100L every 23.68 seconds
or
(100/23.68) * 60 = 253 L/min

 

[WillemBouwer]

CWatters: Yes as stated in A it is a double acting actuator... Let's say that the duration of the strokes is the same so yes thanks, now you made that seem pretty obvious, haha...
Thanks

Now the other thing I started to have trouble with, say I do not want to place a spring for fail safe purposes (load is to big), I am recommending an air receiver.

I however have to size the receiver accordingly. Let's say for only the closing stroke.
I know I have to use Boyle's law: pV = k or p1V1 = p2V2

I've tried a view solutions by now. I don't know what to use as V1 and V2? Do I use the 57 liters as V1 and say V2 = Vreceiver + V1? One of the engineers said that rule of thumb says multiply it by 4 so that gives 228L! But surely I can get to the answer using Boyle's law.

Thanks for the help

 

[CWatters]

I'm afraid that's outside my level of experience.

 

[pmacias]

I would approach this problem by first verifying the accuracy of the calculations provided. It is important to double check all calculations and units to ensure the accuracy of the results. Additionally, I would suggest using standard units for air consumption, such as cubic meters per minute (m^3/min), to make the data more easily comparable to other sources.

To calculate the air consumption rate, we can use the formula:
Air consumption rate = (Air_open + Air_closed)/t

Plugging in the values from the example, we get:
Air consumption rate = (42.92 + 56.5)/11.84 = 8.33 m^3/min

This means that the cylinder actuators on the SKG200 valves require an air consumption rate of 8.33 cubic meters per minute. This information can then be used to determine the appropriate size of compressor needed for your system.

It is also important to consider any potential variations in operating conditions, such as different line pressures or speeds, which may affect the air consumption rate. Conducting experiments or simulations under different conditions can help to provide a more accurate and comprehensive understanding of the air consumption rate for your specific setup.