| 摘要 |
PURPOSE:To maintain a predetermined flow velocity in a passage at a heat-transmitting part and prevent a heat exchanger from generating a malfunction or an accident, by a method wherein the number of circulations through the passage in a heat exchanger is changed over at a predetermined value of the change ratio of operating conditions of the heat exchanger. CONSTITUTION:At the time of operating under a rated load, at gated partition walls 11-14 provided in an inlet chamber 6' for a heat-transmitting medium (sea water) at an end of the heat exchanger and a turning-back chamber at the other end, only a valve 11' is closed and the other valves are opened. As a result, the cooling sea water W1 of about 30 deg.C used as the heat- transmitting medium eneters the chamber 6', passes through about one half of cooling pipes 1, turns back in the chamber 7' at the other end, passes through the rest of the pipes 1, enters a downstream-side partitioned chamber partitioned by the valve 11', and flows out as sea water W2 heated to about 38 deg.C. At the time of operating under 75-50% load, the flow rate q1 of sea water is set to be 1/2-1/4W1, the valve 11' is opened, the other valves 12'-14' are closed, and the number of circulations of q1 through the passage is set at 4. Accordingly, the flow velocity of the sea water in the passage becomes 2q1/W1 times, namely, 1-1/2 times of that under the rated load, so that a flow velocity higher than the scaling limit can be obtained. |
