AN ARPARATUS FOR AUTOMATICALLY REGULATING THE MOISTURE OF AIR
Year: 1879

page_text: LETTERS PATENT to Carl Pieper, Civil Engineer and Patent Agent, of 74, Belle-
Alliance Strasse, Berlin, S. W., Prussia, for the Invention of "AN ARPARATUS
FOR AUTOMATICALLY REGULATING THE MOISTURE OF AIR." A communication
from Hermann Rietschel and Rudolph Henneberg, of Dresden, Saxony.
PROVISIONAL SPECIFICATION left by Carl Pieper at the Office of the Com
missioners of Patents on the 24th January 1879.
CARL PIEPER, Civil Engineer and Patent Agent, resident at 74, Belle-Alliance-
Strasse, Berlin, S.W., Prussia. "AN APPARATUS FOR AUTOMATICALLY REGULATING
THE MOISTURE OF AIR." (A communication from Hermann Rietschel and Rudolph
Henneberg, of Dresden, Saxony.)
This Invention relates to a combined apparatus by means of which the degree
of moisture of the air contained in dwelling and other rooms, and also of heated air
serving for warming purposes, is regulated automatically.
The main features of the arrangement with regard to an air heating apparatus
are the following:-Above the stove located in the heating-chamber a distributer or
atomizer is placed, to which water or steam is admitted by a valve combined with
an electro-magnet in such a manner that a current produced by a galvanic battery
will open the valve, while an interruption of the current causes the valve to be
shut.
The closing and breaking of the circuit is done by an instrument called the
bygroscopic key, in which a hair or other hygroscopic substance causes contact
between two metallic points, when it has shortened by a certain amount on account
of dryness, and on the other hand allows the said points to part from each other
when it has become longer from moisture. This instrument is located in the room
to be warmed, and is inserted into the circuit, so that the galvanic current has to
pass the said metallic points.
By the action of the described valve in combination with the hygroscopic key
alone, the distributer would however be unduly supplied with water or steam when
the air entering into the room from the heating-chamber is dry but of a low

page_text: temperature, or when the stove is not fired at all. A second instrument is therefore
requisite, which breaks the current when the temperature falls below a certain
point. The same has been called the thermoscopic interrupter. It consists of a
metallic thermometer, which is connected with the conducting wire in such a manner
that its pointer will keep the circuit closed when the temperature is above a certain
degree, while as soon as the temperature falls below the fixed point, it breaks the
current and thereby stops the supply of water or steam, although the hygroscopic key
may have closed the circuit.
The said distributer consists of a convex body of metal or other suitable material,
against which a small jet of water or steam is projected, but other equivalent
arrangements may be applied for the purpose.
When the described apparatus is used for regulating the moisture of the air
contained in rooms which are not heated in the manner supposed in the foregoing,
the hygroscopic key, the thermoscopic interrupter and the distributer are located in
any suitable part of such room, but the rest the arrangement remains substan-
tially the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Carl Pieper in the Great Seal Patent Office on the 23rd July
1879.
CARL PIEPER, Civil Engineer and Patent Agent, of 74, Belle-Alliance-Strasse,
Berlin, S.W., Prussia. "AN APPARATUS FOR AUTOMATICALLY REGULATING THE
MOISTURE OF AIR." (A communication from Hermann Rietschel and Rudolph
Henneberg, of Dresden, Saxony.)
This Invention relates to a combined apparatus by means of which the degree
of moisture of the air contained in dwelling and other rooms, or of heated air
serving for warming purposes, is regulated automatically.
The main features of the arrangement with regard to an air-heating apparatus
are the following:-Above the stove E, Fig. 1, located in the heating chamber D, a
distributer or atomizer B (shewn in detail by Fig. 7) is placed, to which water is
admitted by a valve L combined with an electro-magnet (see Figs. 5 and 6), in such
a manner that a current produced by a galvanic battery K, Fig. 1, will open the
valve, while an interruption of the current causes the valve to be shut. Instead of
water steam may be used, but in this case the distributer is not required. The closing
and breaking of the circuit is done by an instrument called the hygroscopic key,
Figs. 2 and 3, and M, Fig. 1, in which a hair or other hygroscopic substance causes
contact between two metallic points, when it has shortened by a certain amount on
account of dryness, and on the other hand allows the said points to separato from
each other, when it has become longer from moisture. This instrument is located
in the room to be warmed, and is inserted into the circuit, so that tho galvanic
current has to pass the said metallic points.
By the action of the described valve in combination with the hygroscopic key
alone, the distributer would however be unduly supplied with water, or in general,
the heating chamber with water or steam, when the air entering into the room from
the heating chamber is dry, but of a low temperature, or when the stove E is not fixed
at all. A second instrument C, Fig. 1, is therefore requisite, which breaks the current
when the temperature falls below a certain point. The same has been called the
thermoscopic interrupter. It consists, as shown by Fig. 4, of a metallic thermometer.
which is connected with the conducting wire in such a manner that its pointer will
keep the circuit clossd when the temperaturo is above the desired degree, whereas
when the temperature falls below the fixed point, it breaks the current and thereby
stops the supply of water, although the hygroscopic key may have closed the
circuit.
The hygroscopic key represented by Figs. 2 and 3 consists of a metallic plate a,
to which a human hair b is attached in the manner shown in the Drawing. This
hair must be duly freed from fatty matter by treatment with an alcali or other
suitable solvent of fat. c is a metallic pin, by preference of copper covered with
platina, which has a slit at the lower end, by means of which it rides on the hair.
At the top the pin c is guided in a bush of ebonite or other non-conducting material
Tho weight of the pin is borne partly by the hair and partly by a spring d adjust-
able by screw d'. This spring is in metallic connexion with the conducting wire k
from the battery; is a metallic tongue, which is in connexion with the wire t
When the
leading to the interrupter, Fig. 4, and which is adjustable by screw e.
pin c is in the position shown by the Drawing, the circuit is open, but it is evident
that when the hair b shortens from becoming dryer, pin c will be raised until it
comes into contact with tongue f, whereby the circuit is closed, so that a current
may then pass from k through d, c, and ƒ to ¹. The screw c is provided with a
pointer, which shows on a dial-ring by how much the screw is turned, whereby a

page_text: great nicety of adjustment of the distance between c and fis ensured; g is a screw
for regulating the position of pin c by means of the hair; and h, h, are binding
screws for the conducting wires. The instrument must be adjusted according to
another hygrometer..
The thermoscopic interrupter, Fig. 4, which is by preference placed in the upper
end of the hot air duct, as shown by Fig. 1, is substantially a metallic thermometer,
consisting of two strips of different metals, having, as for instance, brass and iron, &
different expansibility, the two strips being soldered together and bent by preference
into a spiral. This spiral is at one end in conducting connexion with wire k³, while
the other end forms a pointer, which keeps the circuit closed as long as it remains in
contact with the metallic lug m adjustable on the bow m³, according to the temper-
ature at which the breaking of the current is to take place. The said bow is in
connexion with the wire ; i and are the binding screws for the wires k'
and k³.
Figs. 5 and 6 show the arrangement of valve and of the electro-magnet for
opening it. Whenever the circuit is closed the electro-magnet n, n, will attract its
armature o, whereby a pin scrowed into the same lifts the valve p, so that water or
steam can pass from q¹ through the box q and the pipe to the heating chamber.
In Fig. 1 the water or steam pipe is denoted by the letter I. When the current is
broken, either by the hygroscopic-key or by the thermoscopic interrupter, tho
armature o is released and the valve p shuts again. The connexion between the
electro-magnet, the interrupter, and the battery is established by the wires k³ and
³ respectively.
The distributer, which is represented by Fig. 7, consists of a convex body v of
metal or other suitable material, against which a thin jet of water issuing under a
comparatively high degree of pressure from the orifice w is projected; this jet upon
striking against the body v will be dispersed in very fine drops, which are speedily
evaporated, the steain or vapour thus formed being absorbed by the air. Instead
of the said distributer however other suitable arrangements may be provided for
the purpose; thus, for instance, the water may be allowed to run on a heated
plate, &c.
The
In Fig. 8, 9, and 10, a modified arrangement of hygroscopic key is shown.
hair b is in this case attached at one end to a lever 8, and at the other to a weight t
carried by a seat t¹. The said lever is balanced in such a manner that contact will
be caused between the points 8 and u', when the hair shortens from becoming dry,
while the circuit is maintained open when tho hair is of a length as not to exercise
any pull on the lever 8. The fork 8, in which 8 is pivoted, is isolated by a non-
conducting bush x. It is evident that while the points s¹ and u¹ are in contact, a
current may pass from wire k through 8³, 8, and u to k¹. For the purpose of pre-
venting the hair 6 from being unduly stretched after 8¹ and u have come into
contact with each other, the weight t has been applied. This weight is just suffi-
cient to overbalance the weight on the short arm of lever 8, but while the points a¹
and u are not in contact with each other, or just when they meet, it rests on the
seat t' (see Fig. 10). If the hair should yet become shorter after the said contact
has been established, the weight t will be lifted off its seat t', so as to add but a
trifle to the tension of the hair. 2, Fig. 10, is a screw for the adjustment of the
seat t', while by the set-screw u³, Figs. 8 and 9, and connecting-rod u³, the distance
between the contact-points 8' and u may be regulated, a scale serving to show the
amount by which the screw is shifted. It may yet be observed that all the contact
points of the hygroscopic key, as well as of the thermoscopic interrupter, should be
plated with platina.
The Figures 13, 14, and 15 on Sheet 2 show another modification of the hygro-
These levers are
scopic key, in which a hair acts on each of the levers 8 and u.
both weighted in such a manner that the points s' and u¹ will be kept apart from
each other as long as the hairs do not cause them to come into mutual contact. By
this arrangement the relative motion of the said points with regard to each other

page_text: is increased. If it is desired to cause a greater pressure of the points s' and u' on
each other, two or more hairs may be applied to each lever. For the purpoзo of
preventing an undue straining of the hairs, weights t are used as in the foregoing
modification; t¹ is the seat for supporting the said weights when the hairs have
attained a certain length, and for guiding then while they are lifted. This seat,
which is pressed upward by a spring y² may be adjusted by a knob y connected
with a cam y', the position of the seat being indicated by a pointer z. Instead of
using separate weights t, the sheaves over which the hairs are passed, according to
Figs. 13 to 15, may be made heavy enough to serve as weights, and they may be
guided by levers jointed to the bed-plate of the instrument, and supported by an
adjustable seat similar or equivalent to the seat t'. The length of the hairs can be
regulated by the arrangement shown in Fig. 15, or by any other suitable device.
A modification of the valve arrangement is shown by Figs. 11 & 12. The valve
pis in this case attached to a vertical rod på fastened to the armature o. A shoulder
near the upper end of the said rod forms a second valve p¹. r is a membrane of
india-rubber closing the valve-box g at the top, and fitting tightly around the rod.
Whenever the armature o is attracted by the electro-magnet n, n, the valve p is
opened and p¹ closed, in consequence whereof water or steam may pass from q¹
through q, and out at q. On the other hand, when the current ceases to circulato
in the coils of n, n, the water or steam-pressure acting on valve p¹ causes the
vertical rod with valve p and the armature to be lifted. As soon as p has been
closed, the pressure is thrown on this valve, so as to keep it closed and the armature
lifted until the magnet acts again. The valve p₁, upon being opened, will allow a
small quantity of water or steam to escape, which passes off through pipe g³.
Considering that the battery (which need consist of a few elements only), is in
connexion with the wires k and ³, the course which the current takes will easily
be understood from the Figures 2, 4, and 5.
A single hygroscopic key, with thermoscopic interrupter combined, will serve for
a number of rooms warmed by one heating apparatus, in case these rooms are
used in a similar manner, and if they are to be maintained at the same temper-
ature.
When the described apparatuses are applied for regulating the moisture of the air
contained in rooms which are not heated in the manner supposed in the foregoing,
such as spinning or weaving factories, the hygroscopic key, the thermoscopic inter-
rupter, and the distributer (when used) are located in any suitable part of such
room, but for the rest, the arrangement remains substantially the same as in the
first case.
Having thus described the nature and object of this Invention, and means for
carrying it into practical effect (as communicated to me by the inventors), I would
have it to be distinctly understood that I do not wish to confine the extent of the
said Invention to all the details herein described and shown in the Drawings, as
they may be modified in various manners without departing from the nature and
the object of the Invention, but I claim as new and essential features of the
same,-
-
1. In the hygroscopic key the combination of a hair or hairs with one or with
either contact point of a galvanic circuit, in such a manner that the circuit will be
closed when the hair or hairs shorten from dryness, and broken when they lengthen
from moisture, substantially as and for the purpose described.
2. A valve for the passage of steam or water, so combined with an electro-magnet
and a hygroscopic key that the electro-magnet opens or closes the valve according
as the said key makes or respectively breaks the galvanic current, substantially as
& for the purpose specified.
3. The water-distributer or atomizer, in combination with a valve for the passage
of water operated by an electro-magnet and a hygroscopic key, as hereinbefore
described.

page_text: 4°. The combination with a valve for the passage of steam or water, operated by
an electro-magnet and a hygroscopic key of a thermoscopic interrupter, as specified
and for the purpose stated.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Twenty third day of May, in the year of our Lord 1879.
CARL PIEPER
(LB)