Yes, that's scale, I'm sorry to say. I have had the worst summer ever with these. They're insidious and will contaminate your other plants so, firstly...be careful and keep the infected ones, quarantined until you can eradicate the problem. I have been battling scale on my Stanhopea and with everything I've done, they've come back. I was using neem (w/equal amt. soap), the plant looked clean for a day or two and then....back again! The Stanhopea was severely infected and just tonight, I sprayed rubbing alcohol on the entire plant and in the medium and then rinsed.
Bottom line, you have to get every nook and crevice because these beasts bury themselves inbetween and down into the plant leaves and if one is left unscathed, you can bet they'll multiply faster than rabbits!
Try spraying with the alcohol and be sure to repeat this every other day for at least a week.
Good luck. I know what you're going through.