Gold’s Mattress Radiator

I’ve owned one of Stephen J. Gold’s mattress radiators since the fall of 1989. It’s on a shelf in our office now, a part of the little heating museum that we maintain for the sake of wonder and amusement. Last spring, I got a second mattress radiator when a New Hampshire friend called to tell me that one of his customers, an elderly woman, was selling her house and needed to get that old radiator out of her basement. She didn’t want to throw it away because it was old. I took a long drive and put it in the Windstar. Well worth it. Steven J. Gold of New Haven, Connecticut was the gent who gave the world the first commercially successful radiator. It was successful because it didn’t kill you. Before Mr. Gold we had James Watt, but Mr. Watt’s radiator was just a metal box. Mr. Gold’s, on the other hand, was a thing of beauty. It measures about five feet by three-and-a-half feet, and it’s less than a half-inch thick. It hangs on the wall like a modern panel radiator. There are rivets spaced evenly every two inches across its face, giving it the appearance of a mattress, hence the name. It’s the color of an old penny and it has painted wood grain to enhance its appearance, as well as red and gold lines around the edges. The supply valve is a work of art. Delicately painted in red and green and yellow and gold, it has the words, “Gold’s Patent, October 3, 1854” embroidered with raised letters across the metal.

The radiator I have (the first one) came from a house in Claverack, NY that Deadmen built in 1857. Mattress radiators were still heating that house, and this was the oldest steam system I had ever seen.

Recently, a friend sent me the U.S. patent for Mr. Gold’s radiator. My friend’s been collecting old heating patents, and this one was especially good because Mr. Gold, in his own words, explains to the U.S. Government how his steam heating system (not just his mattress radiator) will work. This is one of the earliest designs for central heating and you can see if for yourself by going to the Library here at Look under Very Old Stuff.

Mr. Gold’s system, which was safe because it ran at such low pressure, was wonderfully simple. I’ll describe it to you and see if you don’t agree.

He set a boiler (which could have been anyone’s) in the basement and ran a steam supply line straight up to the radiators. There was no boiler header, and no Hartford Loop (that shows up 65 years later). There was just a simple steam pipe running straight up. The radiators branch off the supply, and the supply line then continues to a slightly higher level where it enters a metal chamber. This chamber is a bit wider than the supply riser and it contains a conical weight. The wide end of the cone sits on the top of steam supply pipe. The boiler has to build a certain amount of steam pressure to lift that weight, which is an early version of the relief valve. This is what’s going to make steam safe for house heating at a time in America when boilers were exploding every 36 hours. How heavy is the weight? It depends on the pressure needed to run the system, and the vertical space available for the return line. As the boiler fires and builds pressure, the waterline in the boiler is, of course, falling. In Mr. Gold’s system, he’s allowed for a vertical return line that’s equal in height to the weight inside the chamber. Steam, at a pressure sufficient to overcome system pressure drop, travels to the radiators, and any steam pressure in excess of what’s needed lifts the weight and bleeds off. And where it bleeds is delightful.

It goes into a special mattress radiator that acts as a condenser. Mr. Gold tapped this special radiator on its top for the supply, and on its bottom for the return, and he submerged it in a rectangular cistern filled with well water. All the steam from the boiler that’s not entering the radiators in the rooms goes into the condensing radiator and instantly turns into condensate. That condensate then flows down the return line and back into the boiler. He doesn’t say if he uses the water in the cistern as domestic hot water, but doesn’t that just make your imagination soar? What we might have had here was the first indirect water heater.

His patent shows that a part of the return line, positioned just above the height to which boiler water will rise as it backs up the return, is made of glass. This is so the homeowner can monitor the water level during operation. A half-century later, the makers of the famous Broomell steam system, the central heating system preferred by the very wealthy at the turn of the century, will mimic this technique by placing a gauge glass, calibrated to indicate ounces of static pressure, on their return-line receiver. In Broomell’s case, the water backing into the receiver will operate a float ball and chain, which, in turn, will control the dampers. Simply brilliant.

In the return line of Mr. Gold’s system, and just before the section of glass pipe, he has a simple steel elbow. And in that elbow, on its uppermost side, there is a hole. And that hole is the main air vent. No steam would ever reach it. Brilliant. The mattress radiator that I’ve been staring at for the past 15 years has a tapping near its top for an air vent. It’s on the side opposite the supply valve. In 1854, an air vent would have been a very small hand valve. When you wanted heat, you opened the supply valve and bled the air from the radiator. I’ve often wondered how this could have worked since steam is lighter than air. Steam would have entered the mattress radiator, gone straight up and over, and then left through the vent. Most of the air, being heavier than steam, would have remained at the bottom of the radiator and the result would have been uneven heating.

But in reading the patent, I realized that Mr. Gold had also thought of this because there’s a small metal tube that runs from the vent tapping down inside the radiator, and ends near its bottom. So when a homeowner vented, he was actually venting from the bottom of the radiator, and not from the top. A simple dip tube. Nice!

The world you and I live in is wonderfully high-tech. And that makes me appreciate even more the brilliant simplicity of a time long gone when heating was young, and people like Mr. Stephen J. Gold of New Haven, Connecticut came up with ways to keep people warm. And safe.

I appreciate them.

Dan Holohan

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