It
is more than a year ago that I posted the last blog message on PHOAS. The main
reason was my involvement in the Langreuter project, the reconstruction of a
milking machine, working according to a long forgotten principle. I wrote about
it in a blog message posted in June 2015. Since then, my colleague and I did a
lot of research, mainly historical, and presented nine blog messages in Dutch
about the progress of the project; see https://Langreuterproject.wordpress.com. This has many more pictures of objects and details
of patents than can be given here. Below I will present a summary of the project
which came to an end recently. I have omitted the literature references; these
may be delivered on request.
1.
Pictures of the Langreuter milking machine were shown in an earlier blogpost
(June 2015). The machine has two parts, the driver and the milking unit. The
driver is operated manually with a handle, that makes the two cables move the
pressure plates in the milking unit. The plates are moved by the cables in such
a way that they compress the teats in a manner imitating the hands of the
milker: the upper side of the plates move inwards first and start pressing the
teats, the lower side follow a little bit later. The inside of the milking unit
(the walls of the box have been omitted) is schematically represented in fig 1.
Fig 1. Inside of the milking unit,
showing the movable plates.
The cables enter the unit at the
left side.
(Scheme by Marcel van Asselen)
How
the unit works is shown in four short video movies, placed on YouTube:
The
original rubber teat protectors were gone or had lost their elasticity and have
been replaced by (white) linings of polystyrene foam.
The
milking unit is a box with a lid with four holes for the teats, and is
connected to the cow with a strap going over the back. The milk is collected in
a pail placed under the milking unit.
2.
We could not find evidence for the origin of the Langreuter and how and why
it came into possession of the
Veterinary School in Utrecht. The patent description that closely resembles the
design of our Langreuter and that was found in the digital archive of the
German Patent Office, dates from 1910; the archives of the Vetschool, in both
the National Archives in The Hague and the Utrecht Archives, do not contain
information about any acquired apparatus whatsoever in the period between 1910
and 1920. The Maihak Company in Hamburg is still producing things, that have
nothing to do with milking machines (and in the past they produced a lot of
things, e.g. radios, but no milking machines, except this one) and employees of
the company were not able to help us.
However,
the Experimental Dairy Station in Hoorn (NL) tested an electrically driven
Heureka milking machine that looked similar to our Langreuter, except that it
could serve 4 cows simultaneously. In the report, published in 1915, it was
mentioned that the Heureka was provided by a Dutch trading company, giving the
station the opportunity to test the machine. We think that the Langreuter was
obtained by the Vetschool for the same reason, that is, as a test object.
So
far we did not find indications that another Langreuter has ever been built.
3.
The pressure type milking machine had to compete with the vacuum type machine
that imitates the suckling of the calf. The latter type won the competition.
But until 1910 half of all patents granted in the United States concerned
pressure type machines. Many of the patents for this type of milking machine
were granted to Jens Nielsen, a Danish technician from Copenhagen. His patents
can be found in patent archives all over the world. His designs for those
machines show a remarkable agreement in the principles of operation. An example
is the drawing in the patent of 1910, as shown in Fig 2.
Fig 2. Drawings from Patent 54138,
17 september 1910, Schweizerisches Eidgenossisches Amt für Geistlichen Eigentum
Fig 4 and 5 show parts of the
driver, fig 7 and 8 show cross sections through the milking unit.
Several
of Nielsen's machines have actually been built, but never on a commercial
scale. Our Langreuter seems to have been one of them. In Danmark some of the
surviving Nielsen machines can be found in agricultural museums.
A
remarkable coincidence appeared when Nielsen's address, as mentioned in one of
his US patents, was used as a search item on the internet. In 1906 Jens
Nielsen, bicycle merchant, Vester Voldgade 7, Copenhagen, lived opposite to mrs
Mary Langreuter, who ran a boarding-house at Vester Voldgade 8, in the same
year.
4.
Historians of agriculture consider the pressure machine mostly as a footnote to
the history of machine milking. In their opinion, this type of milking was not
able to provide milk with the same quality as that of vacuum milking, because
of an inferior hygiene: difficulties in cleaning the machine and increased risk
of bacterial contamination of the milk and of mastitis. However, some reports
have survived that describe the results of tests of milk quality and quantity
in a comparison of pressure machine milking with hand milking and vacuum
machines. In general, the pressure machines performed well with regard to
speed, quantity and milk hygiene. Not everyone was positive, however; according
to the test results obtained from the Hoorn Experimental Dairy Station, more
milk remained in the udder with the Heureka. In addition, because of the way
the milking unit is attached to the cow, air from the outside has access to the
inside of the milking unit, thereby giving easy contamination of the milk; this
could be overcome by washing the udder before milking, however.
But
the pressure machines, and the Langreuter in particular, had three serious
drawbacks. First, it took too much time to attach and secure the milking unit
to the cow. Second, the cables of the Langreuter driver that move the plates
were prone to rust and got easily broken. Third, and in our view the most
important drawback, the milking unit does not fit to all cows. We have
investigated this in more detail, by measuring the distance between the teats
of the udders of six cows in a milking parlour and compared those with the
distances of the holes of the milking unit. In all cases the unit could not
have been fitted to the udders because of the differences in dimensions. The
distances between teats were very variable, which is not a problem when milking
is done with a vacuum machine with flexible teat cups. This is in accordance
with a warning in the Hoorn test report, that two out of eight cows could not
be milked with the Heureka because of non-fitting dimensions.
After
1915 the pressure machines passed into oblivion and nothing was heard or seen
anymore of them, except in historical reviews and museums.
