Demand regulated electrode-type steam generator

• US 4,221,955 A
• Filed: 08/21/1978
• Issued: 09/09/1980
• Est. Priority Date: 08/21/1978
• Status: Expired due to Term

• Current Assignee: Getinge/Castle, Inc., Santa Barbara Research Center Goleta CA
• Original Assignee: Sybron Corporation (Envista Holdings Corporation)
• Inventors: Joslyn, Larry J.
• Primary Examiner(s): Bartis, A.
• Application Number:
  US05/935,347
• Time in Patent Office: 750 Days
• Field of Search: 219/284-295, 219/271-276, 338/80-86
• US Class Current: 392/328
• CPC Class Codes: F22B 1/30 Electrode boilers

Abstract

An electrode-type steam generator includes a pair of spaced electrodes extending into a pressure vessel having a feed water inlet and a steam outlet. A rotary stirring device, cycled on and off by a pressure switch in the steam outlet, is provided in the vessel below the electrodes and is operative to create a vortex which artificially raises the level of the water adjacent the sides of the vessel without water being added, whereby the electrodes are immersed to a greater extent when the stirrer is operating to increase steam production than when it is not operating. The flow of water into the vessel through the feed water inlet is controlled by a solenoid valve responsive to the current flow between the immersed portions of the electrodes. A pressure operated valve is provided in the feed water inlet upstream of the solenoid valve for overriding operation of the solenoid valve if the pressure in the vessel exceeds a predetermined value, the predetermined value being lower than the pressure at which the pressure switch is operative to cycle the stirrer on and off.

Claims

1. A steam generator comprising:

(a) a pressure vessel having a feed water inlet and a steam outlet;

(b) a pair of immersion heating electrodes extending into said vessel, said electrodes extending adjacent the sides of said vessel and being spaced above the bottom thereof;

(c) stirring means in said pressure vessel adjacent the bottom thereof and vertically spaced below said heater electrodes for driving the water in the vessel through a circular path of travel with sufficient velocity to raise the level of the water adjacent the sides of the vessel up to said heating electrodes whereby more of said heating electrodes is immersed when said stirring means is operating than and when said stirring means is not operating;

(d) a pressure switch connected to said stirring means and acting responsive to the pressure in said steam outlet being below or above a to steam outlet first predetermined pressure and to respectively start or stop said stirring means;

(e) water level control means including a valve in said feed water inlet acting responsive to current flow through said heating electrodes to open or close said feed water inlet; and

(f) a pressure operated valve in said feed water inlet upstream from said valve, said pressure operated valve being adapted to open or close said feed water inlet responsive to the pressure in said pressure vessel being below a second predetermined pressure, said second predetermined pressure being lower than said first predetermined pressure in said steam outlet.

2. In a steam generator including a pressure vessel having a feed water inlet, a steam outlet and employing immersion heating electrodes spaced above the bottom of said vessel and adjacent the sides thereof for boiling the water in said vessel, a method of controlling steam production comprising the steps of:

(a) driving the water in said pressure vessel in a circular motion with sufficient velocity to raise the water level adjacent the sides of said vessel an amount sufficient to immerse at least a portion of said electrodes in the water;

(b) stopping or starting the circular movement of the water in said vessel responsive to the pressure of steam at said steam outlet being respectively above or below a first predetermined pressure;

(c) controlling the water level in said pressure vessel by opening or closing said feed water inlet responsive to current flow through said immersion heating electrodes being respectively below or above a predetermined value; and

(d) overriding step (c) by closing said feed water inlet responsive to the pressure in said vessel exceeding a second predetermined value which is lower than said first predetermined pressure.