Water pump seal coolant wick

A water seal coolant wick comprises a ring of absorbent material, such as felt, disposed in the drain cavity between the inner radial face of a water pump seal in a water pump and the bearing housing so that the wick is disposed in the leakage path between the seal and the drain cavity weep hole, the wick preferably completely filling the drain cavity and acting to absorb insignificant weepage from the seal and keep it within the housing, out of sight, while allowing substantial leakage, which would be indicative of pump failure, to flow out of the weep hole.

BACKGROUND OF THE INVENTION 
The present invention relates cooling water pump assemblies for internal 
combustion engines of the type having a water pump seal for preventing 
leakage of coolant along the pump shaft and, more particularly, to a wick 
for use in collecting and retaining insignificant amounts of coolant which 
escape past the water pump seal before the coolant weepage becomes 
visually noticeable. 
THE PRIOR ART 
Internal combustion engine water pumps typically include a housing in which 
one end of a rotating pump shaft is mounted by bearings and a pumping 
chamber into which the other end of the pump shaft extends and to which 
the pump impeller is attached. A mechanical water pump face seal is 
mounted between the rotating pump shaft and the housing and a weep hole is 
disposed in the housing between the water pump seal and the bearing 
assembly so that any coolant which escapes past the seal will escape from 
the housing, signal a failure of the pump seal, and not otherwise 
interfere with the engine. 
The problem of noticeable insignificant weepage of coolant past a coolant 
seal's primary face and its mating ring has been of long standing. In most 
instances, small amounts of sporadic weepage may occur and leak out of the 
weep hole leaving a visible streak on the housing. Although such small 
weepage is of no consequence in pump function, when noticed by a user, it 
is perceived as a failure of the pump and replacement of the pump is 
sought. A significant number of such replacements have been found to be 
unnecessary. Thus, eliminating visibility of such small, sporadic 
occurrences of weepage is desirable. 
Various complex and expensive methods and structures for eliminating minor 
weepage visibility have been proposed. Examples may be seen in U.S. Pat. 
Nos. 5,131,809, 5,154,576, 5,226,786, 5,336,047, and 5,338,153 and include 
provision of a drip cup for collecting the weepage until it is gradually 
evaporated into the ambient environment, and creating a self-sealing pump 
wherein a secondary seal is created by particulate matter in the weepage 
collecting against a barrier in the flow path, clogging the flow path over 
time and creating a plug in the weepage path which is only overcome by 
excessive leakage signaling required repair. Further as shown in U.S. Pat. 
No. 5,131,809, it is known to provide a porous disk within a waterproof 
cup like member positioned between the weep hole and the bearing assembly 
so that leakage from the primary seal is kept away from the bearing until 
heat from the rotating shaft causes evaporation thereof, with evaporation 
taking place through openings penetrating the bearing cover on opposing 
sides of the shaft. However, this does not solve the problem since small 
amounts of leakage past the seal do not encounter the disk but rather can 
freely exit the housing through the weep hole. 
SUMMARY OF THE INVENTION 
Accordingly, it is a primary object of the invention to provide a simple 
and inexpensive means for eliminating visibility of such insignificant 
weepage while allowing for visibility of significant leakage to signal 
required replacement of a failed pump. 
The object is met by the structure of the present invention which comprises 
a wick of absorbent material abutting against the primary water seal 
between the seal and the weep hole so that insignificant weepage will be 
contained by the wick until evaporated, while significant leakage is 
allowed access to the weep hole.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now the drawings in greater detail, there is illustrated therein 
a water pump 10, such as that used in cooling an internal combustion 
engine (not shown). Such pump 10 includes an impeller 12 mounted on a 
rotating shaft 14, with the rotating shaft being mounted in an outer 
bearing race 24 mounted in a reduced diameter portion of the pump housing 
20 by bearings 16, a bearing seal 17 being disposed between the bearings 
16 and the end of the outer bearing race 17, the reduced diameter portion 
forming a shoulder 28 in the housing. 
As best shown in FIG. 2, a primary fluid seal assembly 18, is placed about 
the shaft 14, interior to the impeller 12, which is located within a fluid 
environment, to keep coolant surrounding the impeller 12 from leaking out 
of the pump housing 20. The primary sealing face 19 is mounted to the pump 
shaft 14 through ceramic cup member 15 press fit on the shaft for rotation 
therewith, the cup member 15 including a sleeve portion 11 disposed about 
the shaft 14 and extends toward the bearings 16. A spring-loaded sealing 
member 21 is mounted by a cup-shaped annular spring retainer 25 having a 
central opening for the shaft 14, the retainer being pressed into a 
cylindrical drain cavity 29 formed between housing shoulder 28 and the 
impeller end of the housing 20 of the water pump so that the sealing 
member 21 is biased by spring 23 against face 19. A rubber bellows 27 
extends about the non-rotating portion of the seal from the spring 
retainer 25 to the sealing member 21. 
Due to the relative rotary motion between the sealing member 21 against the 
sealing face 19, seepage or weepage of the coolant past the primary fluid 
seal 18 may occur. The leakage path extends between the sealing faces 
19,21 and along the outer periphery of the sleeve 11 and through the 
central opening in the spring retainer 25 into the drain cavity 29. The 
drain cavity is provided with a drain groove 31 adjacent the shoulder 28 
and a weep hole 22 is drilled from the drain groove 31 of the housing 
drain cavity 29 to the exterior of the housing so that coolant leaks will 
be transferred outside of the housing and visible if a significant leak 
occurs. 
In accordance with the invention, a coolant wick 30 comprising a 
cylindrical washer-like member of absorbent material, preferably 
extra-firm felt having 80% minimum wool content as defined in SAE Standard 
J-314 promulgated by the Society of Automotive Engineers, is disposed 
about the shaft 14, as by a light press fit thereon, and extends radially 
from the shaft 14 to the limits of the drain cavity 29, excluding the 
drain groove 31. The coolant wick 30 is compressed by the inner face 32 of 
the spring retainer 25 against the bearing race 24 and housing shoulder 28 
such that the wick 30 substantially fills the entire drain cavity 29 and 
covers the entrance to the drain groove 31 and the weep hole 22. The wick 
30 is capable of absorbing and containing small amounts of leakage past 
the sealing faces 19, 21 rather than allowing the leakage to exit the weep 
hole 22. Eventually, heat from the rotating shaft 14, will cause 
evaporation of leakage collected by the wick 30 and escape of the vapor 
through the weep hole 22. However, the absorbent capacity of wick 30 is 
only sufficient to accommodate weepage but is not absorbent enough to 
retain substantial leakage if the pump seal 18 becomes defective, such 
leakage flowing from the weep hole 22. 
As described above, the coolant wick of the present invention provides a 
number of advantages, some of which have been described above and others 
of which are inherent in the invention. Also, modifications can be 
proposed to the wick without departing from the teachings herein. 
Accordingly, the scope of the invention is only to be limited as 
necessitated by the accompanying claims.