No same material same machine process and same hydraulic test pressure procedure the only mechanical difference is the drain positions on the HP drain is to the left (front) and on the Interstage drain it's to the right (back) (This when viewed from the fan side).
An engineering re design proposal for our European military/ pure air applications and scientific air sampling applications because these models are all still currently available and under service contracts is to re position the drains both to the front thus both LP and HP filter shells would be to the same manufacture drawing if or when the Rix stock our ours were ever depleted.
The difference in pricing is basically the economics of scale in the current situation for the now discontinued scuba version of the SA-6
In the good old days from an engineering perspective you would take say the minimum economic quantity to manufacture this would kick off with around 80 meters of solid round bar to get the best pricing, then an auto bar feeder to machine around 400 units Now here's the first kicker the maths don't work as again consideration originally would have to be given for the SA-3 model as that shared a separator with the SA-6 so you end up with odd stock quantities 3rd & 2nd stage.
Now due to both models being discontinued in the USA at some point say when stock is depleted any new filter shell order would require manufacturing consideration and would now be dependant on the quantity ordered against the quantity manufactured. How many would you like so to speak?
Now for the contentious version this is what you get with the corporate mindset of minimum stock levels and those in sales and administration of said stock levels and order processing, as follows:
1. Stock Level Computer tells you you have reached the minimum stock level for the LP shell of lets say say 50
2. Sales computer tells you how many you sold last year lets say 10
3. Accounts computer tells you the profit margin return over time on purchasing another 400 of the little blighters from engineering at say selling 10 a year and you now have 40 years of stock.
4. So Engineering gets a purchase order to manufacture 10 and the minimum stock level problem goes away and all departments are happy.
5. Then everyone gets together around a morning management meeting with tea and biscuits and are surprised that the price went up on the LP filter and not the HP filter while they discuss who gets to sit today in the biggest chair.
Go figure. Iain
