Pulsometer
A pulsometer is a piston-less , steam- powered pump derived from Thomas Savery's steam pump that was used to lift liquids.
origin
The American Charles Henry Hall developed the pulsometer pump in the 1860s. Its results led to 29 patents in 1872 (US patents 131,515 ff.). Through his developments, the difficulties of the pump-external control were solved by relocating it to the inside of the pump: The control of the pump was only dependent on the internal pressure conditions.
principle
The name of the pump is derived from the pulsating mode of operation. It consists of two chambers in which the steam alternately takes effect. The chamber is selected (controlled) by a ball valve : the ball releases the steam for one chamber while it closes the other in a vacuum-tight manner. In the original design, the suction valves (inlet) and the individual pressure valve (outlet) were also designed as ball valves, but later as circular rubber flaps: 2 suction valves and 2 pressure valves (see illustration). The entire control is therefore incumbent on the ball valve in the steam inlet. The position of the steam valve ball depends solely on the pressure difference between the two chambers. In order to minimize the turbulence in the incoming steam, the chambers are funnel-shaped towards the ball valve. In the upper area of each funnel there is a valve that lets ambient air into the chamber when there is a corresponding negative pressure. To reduce cavitation , a suction air vessel is provided in the inlet area , which is spatially positioned between the upper branches of the chambers.
functionality
Assume that the liquid to be pumped is water and that both chambers of the pump are at least partially filled by backflow through the valves. The steam flows through the ball valve into one of the chambers and pushes the water in the chamber through the outlet valve (pressure valve). The inflow swirls the steam, it comes into contact with the air in the chamber, the interior surface of the chamber and also the water surface, whereby it cools and condenses . The condensation of the steam creates a negative pressure. Due to the drop in pressure, on the one hand it is no longer possible for the steam to push water through the drain valve, on the other hand the steam supply is closed off via the ball valve. More and more steam condenses in the chamber, the negative pressure becomes so strong that water flows into the chamber via the suction valve. This water further cools the steam and the chamber continues to fill. The vacuum also opens the vacuum valve at the top of the inlet funnel. The small amount of air flowing in causes turbulence in the steam, causing it to condense faster and more completely. This also reduces the temperature in the chamber. By closing the steam supply when condensation begins in the first chamber, the steam supply into the second chamber has already been released. The processes in the second chamber are analogous to the first. The moment the steam begins to condense in the second chamber, it is released again for the first chamber and the water is pressed out of the first chamber. The first chamber pumping cycle begins again.
Advantages and disadvantages in use
Because of the direct contact of the pump housing with the fluid to be delivered and the driving steam was for liquors from cast iron for, acids from Hartblei manufactured. In addition to the simple construction, the relative insensitivity of the pulsometer to contamination and high temperatures of the liquid to be conveyed is an advantage. Areas of application were, in addition to the drainage of clay pits, also the water supply of steam locomotives on open routes. The steam required for transport was taken from the locomotive's own steam system. The disadvantage is the high steam consumption per pumped amount of liquid compared to other pumps and the heating associated therewith. In bathing establishments where pulsometers were used as water pumps , this warming is in turn an advantage. Due to their inefficiency in converting thermal energy into potential energy , pulsometers are rarely used nowadays.
gallery
- Pulsometer at the Kew Bridge Steam Museum
cast iron pulsometer (Pulsometer Eng. Co. Ltd., London)
Ball valve ( bronze ball )
The discharge chamber of the pulsometer with two rubber flap valves. Drain upwards, cut off the rubber ring of the right valve for functional illustration.
Existing copies
In operation
- A pulsometer from the time the Achenseebahn was built in 1889 was in operation until the end of April 2020 at the end of the mountain at Seespitz am Achensee , Tyrol, Austria. The locomotive, which stopped at the right place, supplied the steam to pump water from the lake a few meters away using the green-painted pump into its water tank. The railway is currently - since the end of April 2020 - with an unclear future.
- In a forum post from July 2020 it is assumed that it is "largely the only one (pulsometer) in the world that is still operational."
- At the final stop at Seespitz, a steam line is screwed to the side of the locomotive with a telescopic tube with a union nut that can be swiveled to the track. Steam is fed to a green lacquered pulsometer with 2 cast iron chambers to suck in seawater and to let it flow through a swivel nozzle into the water tank on the side of the boiler of the locomotive. This steam-driven pump works intermittently and is acoustically reminiscent of a water ram .
Idle, exhibited
- London Museum of Water & Steam (founded in 1975, until early 2014: Kew Bridge Steam Museum)
- Brede, Sussex, England
literature
- Conrad Matschoß: The development of the steam engine . Springer, Berlin 1908, pp. 355-360.
- Reprint: Conrad Matschoß: The development of the steam engine . Springer, Berlin, Heidelberg, New York 1987, ISBN 318400788X , pp. 355-360.
- JA Ewing: Encyclopaedia Britannica , 9th Edition, Volume 22, Charles Scribner's Sons, New York 1887, p. 516.
Web links
Individual evidence
- ↑ https://www.google.de/patents/US131519
- ↑ https://www.google.de/patents/US131515
- ↑ Achenseebahn image film , title in the film: 130 years of the Achenseebahn. Achenseebahn AG, November 27, 2019, accessed July 8, 2020. - Filling the water box with the pulsometer: 1: 56–2: 40/4: 41. 2:35: Imagine lettering on the cast body of the pump: PATENT // PU / LSOMET / ER // MACO. (= Mf.Co. Manufacture Company?)
- ↑ Steam on the Achensee and Zillertal Railway youtube.com, steinerne_ renne, February 28, 2017, accessed July 8, 2020. Title in the film: The Achensee and Zillertal Railway in September 2016. Stephan Szarnecki. - Pulsometer: 0: 28-1: 00/30: 39. Audible pulsation frequency around 0.85 Hz or 50 pulses / minute. Forum post bubi1968 + from 1 week ago.