| 摘要 |
A steam heat exchanger for a wood pulp dryer includes a plurality of tubes. The tubes extend between the ends of the heat exchanger in parallel, spaced-apart relationshi p. There is a steam inlet header near a first end of the heat exchanger and an outlet head er near a second end of the heat exchanger. The inlet header has an inner conduit and a plurality of openings spaced-apart therein for discharging steam from the inner conduit. An outer conduit extends about the inner conduit. The inlet ends of the tubes are connected to the outer conduit. The openings in the inner conduit each have a first end and a second end. The first end is closer to the first end of the inner conduit than the second end. In one embodiment the first end of each of the openings is further from the central axis of the inner conduit than the second end thereof. There may be a mount for the inner conduit which is fixedly connect ed to the outer conduit at a closed outer end thereof. The inner conduit extends slidably in to the second end of the inner conduit. There are at least two rows of tubes, the first row of tubes being first exposed to a flow of air through the heat exchanger. A flow restrictor is located between the inlet header and the tubes of the second row, whereby a flow of steam throug h the second row of tubesis reduced compared to a flow of steam through the first row of tubes. Preferably there are three rows of tubes, the third row being between the first and second rows. |
