A horizontal steam accumulator tank is $60"$ diameter by $20\text{'}$ long. When fully charged the water level is $45"$ above the bottom, and the pressure is $100$ psig. During a test for maximum discharge it was found that the pressure could be dropped to $90$ psig in $10$ sec without throwing water into the discharging steam. Calculate the average rate of steam discharge from the accumulator in lb per hr$.$