Claims
- 1. A heat exchanger, comprising helical coil of tubing having circular fins; helical coil of smaller diameter bare tubing surrounding said first coil; each turn of said second coil contacting adjacent turns of said first coil; both coils manifolded at inlets and outlets.
- 2. A heat exchanger according to claim 1 including an orifice in the inlet manifold to restrict flow to the finned coil.
- 3. A fluid heater comprising:
- a burner comprising a flameholder;
- a first coil of finned tubing surrounding the flameholder and carrying fluid to be heated; and
- a second coil of tubing surrounding the first coil and in contact with fins of adjacent turns of the first coil, the second coil also carrying fluid to be heated.
- 4. A fluid heater as claimed in claim 3 wherein the tubing of the second coil is of substantially smaller diameter than the tubing of the first coil.
- 5. A fluid heater as claimed in claim 4 wherein fluid to be heated is directed into the first and second coils in parallel.
- 6. A fluid heater as claimed in claim 5 further comprising a flow restriction to restrict flow to the finned coil.
- 7. A fluid heater as claimed in claim 3 wherein the burner is a gas burner.
Parent Case Info
This is a continuation of co-pending application Ser. No. 07-287,460 filed on Dec. 21, 1988, now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
Parent |
287460 |
Dec 1988 |
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