Equalization tank for cooling liquid

An equalization tank for a cooling liquid which is subdivided by an essentially perpendicularly disposed interior partition wall into a prechamber and into a suction-discharge chamber; the vent lines which are connected with the cooling water outlet of the cooling water jacket of the engine and with the heat-exchanger thereby terminate in the prechamber whereas the auxiliary return line leading to the circulation pump for the cooling liquid terminates in the suction-discharge chamber; the partition wall is thereby also provided with a connection located near the tank bottom for cooling liquid, low in air or gas bubbles, as also with a vent connection between the prechamber and the suction-discharge chamber which is located near the tank ceiling.

The present invention relates to an equalization vessel or tank for a 
cooling liquid, which is connected on its inlet side by way of at least 
two vent lines and on its discharge side by way of an auxiliary return 
flow line with a main circulatory system for the cooling water, connecting 
both the cooling liquid inlet as also the cooling liquid outlet of a 
cooling liquid jacket of an internal combustion engine with a 
heat-exchanger for the heat transfer, in such a manner that one vent line 
as engine operational vent line is operatively connected continuously with 
the cooling water outlet of the cooling liquid jacket while the other vent 
line is operatively connected with the heat-exchanger and the auxiliary 
return flow line is continuously connected with the cooling water inlet. 
Equalization tanks of this type are known in the art (German Auslegeschrift 
No. 2,058,995) and entail the advantage that also with a closed thermostat 
valve--i.e., when the heat-exchanger is disconnected from the engine 
operational vent line--both the operational venting as also the fill-in 
venting of the heat-exchanger are assured by way of the equalization tank 
by means of the vent line connected with the heat-exchanger. 
The present invention is concerned essentially with the task to further 
improve such equalization tanks in order to assure also with low liquid 
levels in the tank an effective air- and gas-separation out of the cooling 
liquid. 
The underlying problems are solved according to the present invention in 
that an essentially vertically disposed inner partition wall forms a 
subdivision into a prechamber or first separation chamber and into a 
suctioning-off chamber or second separation chamber, in that the vent 
lines terminate in the prechamber and the auxiliary return flow line in 
the suctioning-off chamber, and in that the partition wall is provided 
with a connection for cooling liquid low in bubbles which is disposed at 
the tank bottom as also with a vent connection disposed at the tank 
ceiling between prechamber and suctioning-off chamber. 
In the equalization tank according to the present invention, two venting 
chambers are created by the partition wall which are connected with each 
other at the tank bottom in order to feed the cooling liquid layer which 
is low in gas bubbles or free of gas bubbles, to the orifice of the 
auxiliary return flow line customarily located at the tank bottom, whereas 
the vent particles collect in both chambers in an air chamber space at the 
tank ceiling and the vent connection of the partition wall establishes a 
pressure equalization between the upper air- or gas-bubbles of both 
chambers. It is far-reachingly avoided in this manner that the auxiliary 
return flow line is able to suck in air or gas with a low cooling liquid 
level. 
In order to avoid an excessive throttling in the equalization tank by means 
of the partition wall during larger cooling liquid quantities per unit 
time and in order to permit nonetheless exclusively cooling liquid low in 
gas bubbles or free of gas bubbles to pass through the connection located 
at the tank bottom, it is additionally proposed according to the present 
invention that the partition wall is provided with a third connection for 
cooling liquid enriched with gas bubbles between the prechamber and the 
suctioning-off chamber, which is located geodetically between the vent 
connection and the connection for the cooling liquid low in bubbles. It is 
thereby advantageous if the orifice of the third connection which 
terminates in the suctioning-off chamber is equipped with and shielded by 
means of an obliquely upwardly inclined sheet-metal guide baffle member in 
order to direct the flow in the direction toward the tank ceiling so that 
the air- or gas-bubbles which are still enclosed, are separated with 
certainty at the latest in the suctioning-off chamber. 
The known equalization tank includes a short fill-in pipe connection for 
cooling liquid, to which is connected the vent line connected with the 
heat-exchanger. In the application of the present invention to this known 
equalization tank, provision is made that the short fill-in pipe 
connection terminates in the prechamber. 
It is additionally customary in equalization tanks for cooling liquid to 
provide a pressure equalization valve between the tank interior space and 
the atmosphere. In application of the present invention to an equalization 
tank with a pressure equalization valve, it is proposed that the pressure 
equalization valve is connected with the suctioning-off chamber. It is 
avoided by the partition wall in the equalization tank according to the 
present invention that cooling liquid can be discharged by way of the 
pressure equalization valve owing to an excess pressure in the tank 
interior space since a calm liquid level will always establish itself in 
the suctioning-off chamber and the valve is customarily in operative 
connection with a place near the container ceiling. 
In order to avoid in case of a larger yield of air- or gas-particles that 
non-separated particles can enter into the auxiliary return flow line, it 
is additionally proposed that a sheet-metal shielding member is arranged 
above the opening of the auxiliary return flow line terminating in the 
suctioning-off chamber. 
In a further advantageous embodiment of the equalization tank according to 
the present invention, the arrangement may be made in such a manner that 
the sheet-metal shielding member is inclined to the horizontal plane and 
is provided in its upper part with a vent connection between the section 
of the suctioning-off chamber located on its lower side and the section of 
the suctioning-off chamber located on its upper side. With such an 
equalization tank according to the present invention, the lower portion of 
the sheet-metal shielding member may be located very close to the tank 
bottom in order to permit with certainty that only cooling liquid low in 
bubbles or free of bubbles is able to enter into the auxiliary flow return 
line. On the other hand, it is avoided by the vent line connection that an 
air pocket can form underneath the sheet-metal shielding member. 
Especially in those cases in which only a slight structural height is 
available for the equalization tank, it is advantageous if additional 
guide or deflection means are arranged in the prechamber and are 
interposed from a flow point of view in such a manner between the opening 
of the one vent line terminating in the prechamber and the connections of 
the partition wall that the cooling liquid, enriched with bubbles, of this 
vent line is conducted in the direction toward the tank ceiling. It is 
achieved in this manner that a large portion of the air- or gas-bubbles 
are separated out of the cooling liquid already prior to flowing through 
the partition wall so that the cross section of the connection in the 
partition wall which is located at the tank bottom, can be constructed 
relatively large and a third connection in the partition wall can be 
dispensed with. In order to also conduct the flow layer low or free of 
bubbles at the bank bottom to the auxiliary return flow line without 
significant deflections and the like, when the liquid levels in the 
equalization tank are low, it is additionally advantageous if the 
additional guide means is provided with a connection disposed at the tank 
bottom for cooling liquid low in air- or gas-bubbles between the orifice 
of the one vent line disposed upstream and the connections of the 
partition wall. 
Accordingly, it is an object of the present invention to provide an 
equalization tank for cooling liquid which avoids by simple means the 
aforementioned shortcomings and drawbacks encountered in the prior art. 
Another object of the present invention resides in an equalization tank for 
the cooling liquid of an internal combustion engine which assures an 
effective air- and gas-separation out of the cooling liquid even at low 
liquid levels in the tank. 
A further object of the present invention resides in an equalization tank 
of the type described above in which the particles to be vented collect at 
the tank ceiling and a pressure equalization is established between the 
air- or gas-bubbles in the upper portion of the tank. 
Still a further object of the present invention resides in an equalization 
tank for internal combustion engines in which a sucking-in of air or gas 
into the auxiliary return flow line is precluded also at low liquid 
levels. 
Still another object of the present invention resides in an equalization 
tank of the type described above which avoids unnecessary throttling in 
the various connections thereof while at the same time far-reachingly 
avoiding the admission of non-separated air- or gas-particles into the 
auxiliary return flow line. 
Another object of the present invention resides in an equalization tank for 
internal combustion engines subdivided into two chambers by a partition 
wall, in which the two chambers are interconnected in such a manner that 
the separation of gas and air bubbles is optimally favored. 
A further object of the present invention resides in an equalization tank 
of the type described above which can be readily installed also in case of 
constricted space conditions for the tank.

Referring now to the drawing wherein like reference numerals are used 
throughout the various views to designate like parts, and more 
particularly to FIG. 1, the arrangement of an equalization tank generally 
designated by reference numeral 101 of the present invention can be seen 
from the cooling liquid circulatory system of an internal combustion 
engine 100, schematically illustrated in this Figure. A cooling liquid 
jacket of the internal combustion engine 100 is connected by way of an 
inlet line 107 with a heat-exchanger or radiator 102, whereby the inlet 
line 107 terminates in an upper common collecting box 103. A main flow 
return line 108 leads from a lower common collecting box 104 of the 
heat-exchanger 102 to a pump 105. An engine operational vent line 115 
leads from the cooling liquid jacket of the internal combustion engine 100 
to the equalization tank 101. Furthermore, a vent line 116 leads from the 
upper common collecting box 103 of the heat-exchange 102 to the 
equalization tank 101. The two vent lines 115 and 116 have to be 
correspondingly matched to the pressure conditions. This may take place by 
means of throttles or the like which are installed into the vent lines. 
The equalization tank 101 includes a short fill-in pipe connection 117, a 
pressure equalization valve 118 and a short suction pipe connection 119 
for an auxiliary return line 106 leading to the pump 105. 
In FIG. 2, the equalization tank 101 of the present invention is 
schematically illustrated, partly in cross section. The equalization tank 
101 is subdivided by a partition wall generally designated by reference 
numeral 113 into two chambers, namely, a prechamber or first separation 
chamber 111 and a suctioning-off chamber or second separation chamber 112. 
The partition wall 113 is disposed essentially vertically. The vent line 
116 from the heat-exchanger 102 leads to the fill-in pipe connection 117. 
The so-called engine operational vent line 115 of the internal combustion 
engine 100 and the vent line 116 lead into the prechamber 111. The vent 
line 115 thereby traverses the suctioning-off chamber 112 and the 
partition wall 113 within the lower area thereof. 
A portion of the air separates immediately out of the liquid-air mixture in 
the prechamber 111. An air chamber space is arranged at the tank ceiling 
above chambers 111 and 112. In the suctioning-off chamber 112, the cooling 
liquid free of air is then to be sucked off by the pump 105 by way of the 
pipe stud 119 and the auxiliary return line 106. In order to achieve a 
pressure and liquid level equalization, upper bores 131 and lower bores 
132 are advantageously provided in the vertically disposed partition wall 
113 at or near the tank ceiling 109 and the tank bottom 110, respectively. 
Geodetically between the bores 131 located at the tank or near the tank 
ceiling and the bores 132 located at or near the tank bottom 110, the 
partition wall 113 is additionally provided with a third connection 
generally designated by reference numeral 120 for the passage of cooling 
liquid enriched with air- or gas-bubbles. The opening of the connection 
120 disposed in the suctioning-off chamber 112 is shielded by a 
sheet-metal guide member 121. It is achieved by this arrangement that only 
cooling liquid free of bubbles can reach from the bottom 110 into the line 
106 and the gas bubbles which are still present in the flow quantity of 
the third connection 120, are deflected upwardly, are separated at the top 
of the tank and are able to collect in the air pocket underneath the 
ceiling 109. 
As can be seen from FIG. 2, the vent line 116 from the heat-exchanger 102 
terminates in a short fill-in pipe connection 117. 
A sheet-metal shield member 114 is advantageously arranged above the 
opening of the short suction pipe connection 119, which terminates in the 
interior space of the tank. The sheet-metal member 114 is so constructed 
and dimensioned that only liquid from the bottom 110 of the suctioning-off 
chamber 112 can be sucked off. A vent bore 133 is advantageously provided 
at the upper portion of the inclined sheet metal shield member 114 in 
order to prevent the formation of an air pocket. 
The equalization tank generally designated by reference numeral 201 
according to the present invention, illustrated in FIGS. 3 and 4, involves 
a construction especially suited for constricted conditions in a motor 
vehicle. The equalization tank 201 can be mounted directly on the 
heat-exchanger 102 of FIG. 1. As to the rest, the same requirements are 
made of this tank 201 as are made of the separately arranged tank 101 of 
FIG. 2. 
The equalization tank 201 is also subdivided by means of a partition wall 
213 into two chambers, namely, into a prechamber or first separation 
chamber 211 and into a suctioning-off chamber or second separation chamber 
212. 
Whereas the suctioning-off chamber 212 is provided with a short suction 
pipe connection 219 terminating at the tank bottom 210 for the connection 
of the auxiliary return flow line 106 (FIG. 1), both a short fill-in pipe 
connection 217 for cooling liquid as also a short pipe connection 222 
(FIG. 3) for the connection of the vent line 115 of the internal 
combustion engine 100 (FIG. 1) terminate in the prechamber 211. The 
fill-in pipe connection 217 is additionally provided with a line 
connection 223 for the connection of the vent line 116 of the 
heat-exchanger 102 (FIG. 1). 
The partition wall 213 is correspondingly provided with a connection 232 
located at or near the tank bottom 210 for cooling liquid low in air- or 
gas-bubbles and with a vent connection 231 located at or near the tank 
ceiling 209. A horizontally disposed sheet-metal shield member 214 is 
arranged near the tank bottom 210 above the opening of the short suction 
pipe connection 219 which terminates in the suctioning-off chamber 212. 
A sheet-metal guide member 225 which is disposed at an inclination to the 
horizontal plane is effectively interconnected between the connections 231 
and 232 of the partition wall 213, on the one hand, and the opening 224 of 
the line connection 222 terminating in the prechamber 211, on the other 
hand; the sheet metal guide member 225 guides or directs the flow 
discharged out of the engine operational vent line 115 into the prechamber 
211 in the direction toward the tank ceiling 209 and is provided with a 
connection 226 located at or near the tank bottom 210 for the passage of 
cooling liquid low or free in bubbles. It is achieved by this arrangement 
that the opening 224--through which flows in the larger portion of the 
through-flow quantity per unit time of the equalization tank--has a large 
spacing with respect to the suction pipe connection 219 and with respect 
to the suctioning-off chamber 212 while the associated flow particles of 
this opening 224 are deflected several times and as a result thereof air 
or gas particles enclosed therein are effectively separated out. A free 
flow cross section 227 of the sheet-metal guide member 225 is provided at 
the height of the tank ceiling 209 and brings about that the throttling 
effect of the sheet metal guide member 225 is not excessive and the gas- 
and air-particles are absorbed with certainty by the gas or air pocket 230 
(FIG. 4) in contact with the tank ceiling wall 209. 
A pressure equalization valve 218 is interconnected between the interior 
space of the suctioning-off chamber 212 and the atmosphere whose valve 
connection on the chamber side is connected with the longer leg 234 of a 
U-shaped pipe generally designated by reference numeral 229. The orifice 
of the shorter leg 235 of the U-shaped pipe 229 which is located near the 
tank ceiling 209 assures the presence of a continuous air pocket. 
It is particularly advantageous to construct the equalization tank 
according to the present invention either completely or partly of 
synthetic plastic material of any suitable type, such as synthetic 
resinous material. Considerable savings in weight and cost are achieved 
thereby and the manufacture is considerably simplified. 
While we have shown and described only two embodiments in accordance with 
the present invention, it is understood that the same is not limited 
thereto but is susceptible of numerous changes and modifications as known 
to those skilled in the art, and we therefore do not wish to be limited to 
the details shown and described herein but intend to cover all such 
changes and modifications as are encompassed by the scope of the appended 
claims.