Gary Kubicek Loco-Notes - Revision history

Dnevil: /* Part 2 */

2021-06-01T18:01:13Z

Part 2

← Older revision		Revision as of 13:01, 1 June 2021
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	== Part 2 ==		== Part 2 ==
			How an Injector Works
			and
			How to Make an Injector Work

			Giffard in 1858 spent quite a bit of time trying to get steam engineers interested in his new invention, the injector. Word finally got around that the injector would work but many people using steam equipment still refused to believe that so simple a device could force water into a hot boiler with nearly 100 percent efficiency! In fact, I showed an injector to a nationally known engineering consultant on gas and liquid flow and told him its purpose and he told me he didn't believe it could or would work. This was in 1965. We discussed the gadget (injector) in mathematical terms and after several hours he admitted that an injector would work.

			This mathematical discussion is interesting because although what is called an energy balance in the injector was understood as far back as 1886, a full understanding of gas and liquid flow dynamics was not developed until the 1930's and even today a fully defined flow equation cannot be solved in certain specific instances because of non-linearities in the physical reactions of some of the guilds (gas or liquid).

			For the steam locomotive enthusiast however, the operation of an injector can be easily explained. A simple injector consists of a casing, a steam nozzle, a combining code, a delivery code, and a check valve. See Figure 1. Steam enters the steam nozzle at low velocity (20 feet/second approximate) but is accelerated to a high velocity (2800 feet/second) by the shape of the nozzle. This high velocity steam combines with water at low velocity (5 feet/second) to speed up the water which enters the delivery cone. The water enters the delivery code at medium velocity (150 feet/second) but at very low pressure and the expansion of the back of the delivery cone reduces the velocity of the water resulting in an increase of water pressure sufficient to overcome friction in the boiler feed pipe, the boiler check valve, and the boiler pressure. The injector check valve has two uses. When starting the injector, before the water can be accelerated, some of the water hit by the high velocity steam cannot enter the delivery cone and must therefore be exhausted to the outside of the injector casing. When the injector is operating, however, the medium speed flow of the water would tend to entrain air and carry this air into the boiler. This is not desirable since it not only reduces the capacity of the injector but oxygen in the air is not desirable inside the boiler. The check valve closes when the injector is in operation shutting off the air supply - there is a vacuum created in the combining cone chamber since whatever air is there is entrained in the water stream and no more air can enter.

			Note: [[Dick Bagley]], who is well known for his many years of activity in building and operating steam equipment, has published in the [[Riverside Live Steamers]] <i>Chronicle</i>, a very concise and well written description of how an injector works. I choose, however, to describe the operation in a more detailed way.


	[[File:LocoNotes-2-Fig1A.PNG\|thumb\|center\|300px\|Figure 1 - Simplified Injector]]		[[File:LocoNotes-2-Fig1A.PNG\|thumb\|center\|300px\|Figure 1 - Simplified Injector]]

Dnevil: /* Part 2 */

2021-06-01T02:22:05Z

Part 2

← Older revision		Revision as of 21:22, 31 May 2021
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	[[File:LocoNotes-2-Fig6.PNG\|thumb\|center\|500px\|Figure 6 - Test of Improved Injector]]		[[File:LocoNotes-2-Fig6.PNG\|thumb\|center\|500px\|Figure 6 - Test of Improved Injector]]

			[[File:LocoNotes-2-Fig7.PNG\|thumb\|center\|500px\|Figure 7 - Sizes of Orifices]]

			[[File:LocoNotes-2-Fig8.PNG\|thumb\|center\|500px\|Figure 8 - Injector Delivery Cone Equation]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T02:07:22Z

Part 2

← Older revision		Revision as of 21:07, 31 May 2021
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	[[File:LocoNotes-2-Fig4.PNG\|thumb\|center\|300px\|Figure 4 - Injector Manual Control]]		[[File:LocoNotes-2-Fig4.PNG\|thumb\|center\|300px\|Figure 4 - Injector Manual Control]]

	[[File:LocoNotes-2-Fig5.PNG\|thumb\|center\|~~300px~~\|Figure 5 - Test of Injectors]]		[[File:LocoNotes-2-Fig5.PNG\|thumb\|center\|500px\|Figure 5 - Test of Injectors]]

			[[File:LocoNotes-2-Fig6.PNG\|thumb\|center\|500px\|Figure 6 - Test of Improved Injector]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T01:53:28Z

Part 2

← Older revision		Revision as of 20:53, 31 May 2021
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	[[File:LocoNotes-2-Fig3.PNG\|thumb\|center\|300px\|Figure 3 - Injector Starter Valve]]		[[File:LocoNotes-2-Fig3.PNG\|thumb\|center\|300px\|Figure 3 - Injector Starter Valve]]

	[File:LocoNotes-2-Fig4.PNG\|thumb\|center\|300px\|Figure 4 - Injector Manual Control]]		[[File:LocoNotes-2-Fig4.PNG\|thumb\|center\|300px\|Figure 4 - Injector Manual Control]]

			[[File:LocoNotes-2-Fig5.PNG\|thumb\|center\|300px\|Figure 5 - Test of Injectors]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T01:47:24Z

Part 2

← Older revision		Revision as of 20:47, 31 May 2021
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	[[File:LocoNotes-2-Fig2.PNG\|thumb\|center\|300px\|Figure 2 - Injector jets]]		[[File:LocoNotes-2-Fig2.PNG\|thumb\|center\|300px\|Figure 2 - Injector jets]]

	[[File:LocoNotes-2-Fig3.PNG\|thumb\|center\|300px\|Figure 3- Injector Starter Valve]]		[[File:LocoNotes-2-Fig3.PNG\|thumb\|center\|300px\|Figure 3 - Injector Starter Valve]]

			[File:LocoNotes-2-Fig4.PNG\|thumb\|center\|300px\|Figure 4 - Injector Manual Control]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T01:27:45Z

Part 2

← Older revision		Revision as of 20:27, 31 May 2021
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	[[File:LocoNotes-2-Fig2.PNG\|thumb\|center\|300px\|Figure 2 - Injector jets]]		[[File:LocoNotes-2-Fig2.PNG\|thumb\|center\|300px\|Figure 2 - Injector jets]]

			[[File:LocoNotes-2-Fig3.PNG\|thumb\|center\|300px\|Figure 3- Injector Starter Valve]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T01:17:06Z

Part 2

← Older revision		Revision as of 20:17, 31 May 2021
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	== Part 2 ==		== Part 2 ==

	[[File:LocoNotes-2-Fig1A.PNG\|Figure 1 - Simplified Injector]]		[[File:LocoNotes-2-Fig1A.PNG\|thumb\|center\|300px\|Figure 1 - Simplified Injector]]

	[[File:LocoNotes-2-Fig2.PNG\|Figure 2 - Injector jets]]		[[File:LocoNotes-2-Fig2.PNG\|thumb\|center\|300px\|Figure 2 - Injector jets]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 2 */

2021-06-01T01:14:15Z

Part 2

← Older revision		Revision as of 20:14, 31 May 2021
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	== Part 2 ==		== Part 2 ==

			[[File:LocoNotes-2-Fig1A.PNG\|Figure 1 - Simplified Injector]]

			[[File:LocoNotes-2-Fig2.PNG\|Figure 2 - Injector jets]]

	== Part 3 ==		== Part 3 ==

Dnevil: /* Part 1a */

2021-05-15T15:43:27Z

Part 1a

← Older revision		Revision as of 10:43, 15 May 2021
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	[[File:Application of Surge Tube.PNG\|thumb\|center\|500px\|Application of Surge Tube.]]		[[File:Application of Surge Tube.PNG\|thumb\|center\|500px\|Application of Surge Tube.]]

			There is one more fact that should be discussed concerning steam generation in boilers. We have engineering knowledge which tells us how much heat energy is developed when burning a pound of fuel. We must be able to analyze where this heat goes and what it does. For that reason the following explanation is given.

			One of the things that the average person doesn't know about steam is that steam has what is referred to as both internal energy and external energy. What this means is that when liquid is converted to water vapor (steam) an amount of heat energy is absorbed in the process and cannot be used to produce work. This is referred to as the internal energy and the only way to get this energy back is to re-convert the steam back to water. This internal energy must be considered whenever a heat balance is calculated to determine how much steam can be obtained when burning a given amount of fuel. The value of energy involved in the conversion of water to steam is roughly 800 BTU's per pound of water. The actual value is given in the table since the actual value is dependent on the temperature of the steam. This simply means that all of the heat energy developed by burning fuel to generate steam is not usable to do work.

			This fact is important if the heat balance of the boiler is to be determined. A consideration of this information will fall more properly in the area of heat energy calculations in the combustion process and how this effects locomotive performance - A topic for a later discussion.

	[[File:Properties of Saturated Steam.PNG\|thumb\|center\|500px\|Properties of Saturated Steam.]]		[[File:Properties of Saturated Steam.PNG\|thumb\|center\|500px\|Properties of Saturated Steam.]]

Dnevil: /* Part 1a */

2021-05-15T15:35:26Z

Part 1a

← Older revision		Revision as of 10:35, 15 May 2021
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	[[File:Priming with Safety Valve over Crown Sheet.PNG\|thumb\|center\|500px\|Priming with Safety Valve over Crown Sheet]]		[[File:Priming with Safety Valve over Crown Sheet.PNG\|thumb\|center\|500px\|Priming with Safety Valve over Crown Sheet]]

			Secondly, and for the same reason, the boiler outlet to the cylinders must be placed high in the boiler (in the steam dome) to prevent [[Priming\|priming]]. Water carried over through the throttle may loosen a cylinder cover through hydraulic pressure. Superheaters on small locomotives tend to prevent this since the water carried into the dry pipe by [[Priming\|priming]] is changed to steam in the superheater tubes. In some cases a sieve (drilled plate) in the bottom of the steam dome also helps keep water out of the dry pipe as well as providing support for the dry pipe.

			Thirdly, the rapid agitation of the water in the firebox area will directly affect the reading in the water glass. The upper connection to the water glass must either have an anti-surge tube extending into the boiler (simple to make) or in many cases an anti-surge column is mounted behind the water glass to reduce water glass fluctuations and thereby provide more accurate readings.

			The anti-surge tube is simply a small diameter piece of tubing with some small drilled holes in the top. The tube extends several inches into the boiler.

			The anti-surge water column, which is more easily mounted on completed boilers, is a piece of tubing with an internal diameter about twice that of the opening in the water glass. The water glass is mounted on the surge tube with the upper and lower ends of the surge tube connected to the boiler. The surge tube is generally slightly longer than the water glass.

	[[File:Application of Surge Tube.PNG\|thumb\|center\|500px\|Application of Surge Tube.]]		[[File:Application of Surge Tube.PNG\|thumb\|center\|500px\|Application of Surge Tube.]]