[0001] The present invention relates to automobile radiators and engines and preventing
corrosion in the cooling system especially those with components of dissimilar metal
construction. (Engines with aluminum heads and iron blocks and steel radiators, engines
of all aluminum construction with steel radiators and engines of iron construction
with radiators of aluminum construction.) It is these types of combinations that present
the most problems regarding cooling system corrosion.
[0002] Automobile cooling systems use water and coolant/antifreeze liquids circulated through
the water jackets of the engine, heads and water pump to effect heat transfer. Then
the hot liquid is piped back to the radiator/storage tank which is a liquid to air
heat exchanger. A typical radiator is made up of a storage tank either above or to
the side of the cooling tubes and exchanged cooling fins. This storage tank has an
opening to the interior of the storage tank part, a core of cooling tubes which is
where the coolant liquid flows and connected to these cooling tubes are fins which
transfer heat to the air which is pulled or pushed through the fins and around the
tubes for heat transfer from the coolant to the air passing through.
[0003] Radiators and engines were historically made of iron and steel which as similar metals
had little corrosion caused by electrolytic activity. Any engine/head/radiator combination
of dissimilar metals is very vulnerable to corrosion because of this electrolytic
activity. In such cases the aluminum components corrode and become porous and may
begin to leak in as little as 12 to 24 months.
[0004] It is the electrolytic activity, where one of the metals act as an anode and corrodes
and other metals act as a cathode and do not corrode. Consequently, corrosion inhibitors
have been developed to prevent corrosion. Chemical corrosion inhibitors can inhibit
electrolysis, but are toxic, present problems to the environment and problems of disposal.
[0005] Sacrificial anodes, constructed of magnesium, aluminum, zinc or combinations thereof
have also been used as corrosion inhibitors. U.S. Patent No. 5,292,595 describes a
sacrificial anode of specified composition bonded to the core metal to prevent the
occurrence of pitting corrosion of core material in a heat exchanger such as a radiator
or heater core.
[0006] Unfortunately such an anode is hard to access to check its condition or replace it
when it wears out. A need exists for a corrosion inhibiting sacrificial anode which
is easily accessible. Since a sacrificial anode is designed to be consumed, easy accessibility
would allow verification of its effective working status and efficient replacement
when depleted.
[0007] A radiator cap is provided which includes a handle portion, a sealing gasket portion
and a sacrificial anode to inhibit corrosion of automobile engine components and radiators/heater
cores. In one aspect, the radiator cap includes a first gasket adjacent to the handle
portion and a second gasket which is coaxial with and is spring loaded in relation
to the first gasket. A sacrificial anode mounting post is attached coaxially to the
second gasket sealing area.
[0008] Embodiments of the present invention will now be described by way of example only,
with reference to the accompanying drawings, in which:-
Fig. 1 is a top view of a radiator cap according to the present invention.
Fig. 2 is a side view of the radiator cap shown in Fig. 1.
Fig. 3 is a perspective view of a radiator with a radiator cap according to the present
invention.
[0009] In accordance with the present invention, a radiator cap contains an integral sacrificial
anode that inhibits corrosion of metal components of the radiator. Placement of the
sacrificial anode on the radiator cap allows for convenient verification of the condition
of the sacrificial anode. Moreover, a worn out sacrificial anode is easily replaced
by either changing the entire radiator cap or by merely replacing the sacrificial
anode.
[0010] A radiator cap having a sacrificial anode according to the present invention is illustrated
in Figs. 1 and 2. The radiator cap 10 includes a handle 12 with grips 14. Two lip
catches 16, in distal relation to each other, are provided to engage the rim of the
opening to a radiator. The radiator cap 10 includes a gasket portion which provides
a water-tight seal. The gasket portion includes a first gasket 18 positioned adjacent
the interior of the handle 12. A second gasket 20 is mounted under tension provided
by a spring 22 and support shaft 24 coaxial with the first gasket 18. A sacrificial
anode 26 is mounted coaxially onto the second gasket 20.
[0011] In operation, the radiator cap 10 is adapted to seal the radiator and place the sacrificial
anode 26 into the radiator's coolant fluid. Cathodic protection is provided by making
the radiator components cathodic to the sacrificial anode and providing sufficient
voltage between the two electrodes. The sacrificial anode 26 is slowly consumed during
the protection process while generating an electrical current. Sacrificial anodes
of zinc, magnesium, aluminum alloy or combinations thereof may provide the potential,
or inert anodes such as graphite, stainless steel, or platinum coated titanium may
be used with power supplied from a rectifier. Various sacrificial anodes are known
in the art. Thus, the radiator cap 10 is placed over the opening to the radiator and
closed, thereby inserting the sacrificial anode 26 into the coolant fluid contained
in the radiator. Fig. 3 illustrates a radiator 30 and a radiator cap 10 according
to the present invention. The radiator 30 includes an upper tank portion 32, a core
portion 34 and a lower tank portion 36.
[0012] The sacrificial anode 26 may be checked periodically to see if it is reaching the
end of its useful life. Indeed, placement of the sacrificial anode 26 directly onto
the radiator cap 10 facilitates viewing at little or no cost. When the sacrificial
anode 26 is depleted, the radiator cap 10 is simply replaced at nominal cost. Alternatively,
the sacrificial anode 26 is made detachable and is removed from the radiator cap 10
when its useful life has expired. A new sacrificial anode 26 is then secured in place
of the expired sacrificial anode 26. Various detachable securing devices such as snaps
and screw assemblies are known in the art and are suitable for use in accordance with
the present invention.
[0013] The above disclosure and examples should not be considered as limitations of the
various embodiments and iterations of a radiator cap having an integral sacrificial
anode. Modifications may be made by those with skill in the art to the embodiments
described above. For example, various radiator caps are and have been used on all
manner of motor vehicles that could be modified to receive a sacrificial anode as
long as the anode is of sufficient length to be immersed in coolant fluid contained
in the radiator. Likewise, any sacrificial anode known to those with skill in the
art that is appropriately dimensioned and configured can be used in accordance with
the present invention. While the gasket portion and the sacrificial anode are described
above as being coaxial, it is contemplated that various other orientations and configurations
may be assumed. Indeed, the sacrificial anode may be attached at any suitable point
on the radiator cap and is not limited to being attached to a gasket. Furthermore,
any radiator which is capable of receiving a radiator cap may be utilized in accordance
with the present invention. Consequently, it is clear that modifications may be made
by those with skill in the art that are within the following claims.
1. A radiator cap comprising:
a) a handle portion having an engaging means configured to engage a rim surrounding
an opening of a radiator for securing the radiator cap to the radiator;
b) a gasket portion disposed below the handle portion and depending from the inner
surface of the handle portion having a first gasket positioned adjacent to the handle
portion and a second gasket spaced axially downward from the first gasket by a predetermined
distance, wherein the gasket portion cooperates with the handle portion such that
when the radiator cap is placed onto the rim surrounding the opening of the radiator,
the first and second gaskets seat against different parts of upper and lower rims
surrounding the opening of the radiator thereby providing a seal; and
c) a sacrificial anode for inhibiting erosion of the radiator and engine components,
the sacrificial anode depending from an interior surface of the radiator cap and configured
to extend from the interior surface of the radiator cap coaxial with and into the
radiator, the sacrificial anode being only below the gasket portion second gasket
such that the end of the sacrificial anode distal from the interior surface of the
radiator cap is at least partially immersed in fluid contained in the radiator,
whereby the radiator cap can be periodically removed from the radiator in order to
monitor the state of the sacrificial anode.
2. A radiator cap according to claim 1 wherein the gasket portion includes a first gasket
adjacent to and coaxial with the handle portion, a second gasket coaxial with and
in spring loaded relation to said first gasket, and the sacrificial anode coaxially
attached to the second gasket.
3. A radiator cap according to claim 1 wherein the sacrificial anode is detachably mounted
to the radiator cap.
4. A radiator comprising:
a) an upper tank portion, a core portion, and a lower tank portion, the upper tank
portion including an opening for receiving a radiator cap; and
b) a radiator cap having
i) a gasket portion with a first gasket and a second gasket spaced axially downward
from the first gasket by a predetermined distance; and
ii) an integral sacrificial anode configured to depend from an interior surface of
the radiator cap, the sacrificial anode being only below the gasket portion second
gasket, and configured to extend into the radiator and be of sufficient length such
that the end of the sacrificial anode distal from the interior surface of the radiator
cap is at least partially immersed in fluid contained in the radiator,
whereby the radiator cap with sacrificial anode assembly can be periodically removed
from the radiator in order to monitor the state of the sacrificial anode.
5. A method of inhibiting erosion in a radiator and engine components comprising the
steps of:
a) providing a radiator cap with i) a gasket portion with a first gasket and a second
gasket spaced axially downward from the first gasket by a predetermined distance;
and ii) an integral sacrificial anode configured to depend from an interior surface
of the radiator cap, the sacrificial anode being only below the gasket portion second
gasket, and configured to extend into the radiator and be of sufficient length such
that the end of the sacrificial anode distal from the interior surface of the radiator
cap is at least partially immersed in fluid contained in the radiator;
b) inserting the sacrificial anode into the radiator;
c) contacting the end of the sacrificial anode distal from the interior surface of
the radiator cap with fluid contained in the radiator;
d) closing the radiator with the radiator cap; and
e) allowing the sacrificial anode to be consumed during operation of the radiator
whereby consumption of the sacrificial anode inhibits erosion of the radiator and
engine components and further whereby the radiator cap can be periodically removed
from the radiator in order to monitor the state of the sacrificial anode.
6. A method according to claim 5 further comprising periodically removing the radiator
cap and monitoring the condition of the sacrificial anode.