Skimmer seal for swimming pool

An improved seal for insertion into a skimmer of a swimming pool that attaches to an intake pipe of the pool filtration equipment and extends into the walled region of the skimmer to provide a compressible body absorbing the expansion of ice during freeze-up of the pool. The seal comprises an air valve for introducing air via an inner shaft into the intake pipe line to clear out water. The seal obviates having to lower the pool water level.

BACKGROUND OF THE INVENTION 
The present invention relates to swimming pools and in particular to a 
device for protecting a pool skimmer and water lines from freezing during 
cold weather. 
Swimming pools located in climates where water freezes are winterized in 
order to avoid damage to pipes and other parts of a pool system such as in 
the region of a pool skimmer. One method of winterization has been to 
insert a funnel into an intake pipe opening and insert an air compressor 
hose into the funnel opening in order to force air into the pool lines to 
clear the lines of water. However, a problem with this method is that the 
funnel does not completely seal the opening to the intake pipe. Also, to 
perform this method the pool has to be drained below the skimmer to remove 
all water from the skimmer area so that the water does not enter the 
intake pipe after the lines have been cleared of water. However, it is 
desirable to maintain a significant amount of water in the pool to prevent 
inward collapsing of the pool due to frost in the ground pushing against 
the pool walls. 
In U.S. Pat. No. 3,552,567, a cylindrical shaped device is described that 
is positioned inside a pool skimmer with one end being screwed into an 
intake pipe for drawing water from the pool to a pump and filter. The 
device has a blow-molded body formed of resilient resin material and it 
has a diameter larger than the intake pipe. At the top of the body of the 
device is a crossbar projection extending upward to provide a finger grip 
for screwing the device into the intake pipe. With the device in place, 
the intake pipe is protected from ice or debris and the device extends 
above the intake pipe into a walled region of the skimmer where it can be 
compressed by expanding ice to protect walls from ice pressure. The 
resilient material forming the device body and the air it contains are 
readily compressed by expanding ice. However, this device does not provide 
for clearing water from the intake pipe to the filter system. 
In U.S. Pat. No. 5,225,075, a skimmer winterizing plug for a swimming pool 
is described that is screwed into a threaded port of a skimmer. The plug 
includes an air valve through which air can be introduced and the air is 
discharged into a downwardly extending flexible tube or hose. An air pump 
attached to the air valve provides air into the line which causes the 
water level in the line to be lowered to a desired level below a 
winterizing level for the pool; thus making the pipe less vulnerable to 
damage by water freezing. However, this plug is useful only when the water 
level of the pool is lowered significantly resulting in no water being in 
the skimmer, and the air does not clear the pipe of water to which it is 
introduced. 
The present invention is an improvement over the prior art for providing 
winter protection for the pool skimmer and water line extending from the 
skimmer. 
SUMMARY 
It is an object of this invention to provide an improved winterizing 
apparatus for a skimmer of a swimming pool without requiring the pool 
water to be lowered below the skimmer. 
It is another object of the invention to prevent a pool skimmer from 
breaking in freezing weather conditions by absorbing pressure from ice 
build-up in the skimmer. 
It is a further object of the invention to provide for clearing the water 
out of the intake water line connecting to filtration equipment in order 
to maintain air pressure in the water lines while water remains in the 
skimmer. 
The objects are further accomplished in a swimming pool having a skimmer 
including a walled region and an intake water line for connection to 
filtration equipment, by a seal for protecting the skimmer and the water 
line from ice damage comprising a partially hollow substantially closed 
body having an outer wall of resilient material, the body extending from 
the intake water line to be compressibly disposed within the skimmer 
walled regions, a first end of the body having valve means for introducing 
and maintaining air under pressure to the intake pipe, a second end of the 
body having a cylindrical projection, the projection having external screw 
threads for threading into the intake water line, and means within the 
body extending from the first end to the second end for directing the air 
through the body. The valve means comprises a self-sealing air valve. The 
first end further comprises a crossbar means extending upward, having the 
valve means positioned in the center of the crossbar, for providing a 
finger grip to screw the seal into the intake water line. The self-sealing 
air valve seals a pocket of air in the water lines to prevent water from 
reentering the water lines from the skimmer. The outer wall of the body 
comprises blow-molded plastic for allowing the seal to expand and contract 
as ice accumulates in the skimmer. The air directing means comprises a 
cylindrical shaft having a strong wall for preventing expansion and 
contraction of the shaft walls thereby preventing the forced air from 
fracturing the shaft.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
Referring to FIG. 1 a seal 10 is shown having a blow-molded body 12 that 
forms the outside of the invention which is substantially closed and 
formed of resilient resin material. The body 12 of the seal 10 is 
generally cylindrical as shown and has a hollow inner cylindrical shaft 16 
running from top to bottom of the body 12. The wall of the inner shaft 16 
is made from a strong plastic material in order to prevent expansion and 
contraction of the inner shaft wall 16. 
Referring to FIG. 2 and FIG. 3, a plan view of the body 12 is shown in FIG. 
2 comprising a self-sealing air valve 18 which is positioned in the center 
of an X-shaped crossbar projection 20 that extends upwards to permit a 
finger grip for screwing the body 12 into an intake water line or pipe 
(not shown). At the bottom of the body 12 a cylindrical projection 22 
extends downward from the body 12 and has external threads 24 for 
threading into the internal threads of the intake water line or pipe 
connected to pool filtration equipment. Projection 22 and threads 24 can 
be made in different sizes to fit different intake water lines as desired. 
When the water line is not provided with threads an adapter (not shown) 
can be used having threads on one end and the other end having a slightly 
smaller diameter for inserting into the water line thereby providing a 
tight friction fit. FIG. 3 is a bottom view of the cylindrical projection 
22 showing the circular opening for air flow to the water line. 
The operation of the seal provides for winterization of swimming pools 
without having to lower the water level. When the seal 10 is screwed into 
the intake water line which leads to filtration equipment, an air pump is 
connected to the air valve 18 and air is forced through the air valve 18 
under pressure into the intake water line. As the air pressure increases 
in the water line, water is forced out and when the air pump is removed, 
air remains in the shaft 16 of the seal 10 and in the water line, thereby 
preventing any freeze-up problems. The water is allowed to remain in the 
pool and the skimmer and the resilient material of the outer wall 12 of 
the seal 10 can be compressed by expanding ice, thereby protecting the 
walls of the skimmer from ice pressure. 
Referring now to FIG. 4, another embodiment of the invention of a seal 30 
is shown having a resilient body 32 forming the outside of the invention, 
and it is substantially closed and formed of resilient resin material. An 
upper portion 33 of the body 12 has generally a cylindrical shape and a 
plurality of vertically stacked sections 34 having alternating concave 36 
and convex 38 edges forming a side wall. A lower portion 42 of the body 32 
comprises a conical shape with a cylindrical projection 44 extending from 
the bottom of the truncated lower portion 42, the cylindrical projection 
44 extending downward from the conical portion 42 and has external threads 
46 for threading into an adapter as described hereinbefore or into a water 
intake line connected to pool filtration equipment. The top of the body 32 
comprises a self-sealing air valve 46 which is positioned in the center of 
pie-shaped projections 48 that extend upward to permit a finger grip. FIG. 
5 is a plan view of the seal 30 showing the air valve 46 in the center of 
the pie-shaped projection 48. A hollow inner cylindrical shaft 40 extends 
from the top to bottom of the body 32. The wall of the inner shaft 40 is 
made from strong plastic material to prevent expansion and contraction. 
FIG. 6 shows a bottom view of the cylindrical projection 44 showing the 
circular opening for air flow to the water line. 
Referring now to FIG. 7, another embodiment of a seal 60 is shown 
comprising a body 62 having a ninety degree elbow shape for positioning in 
a water line of a pool requiring such a configuration. This embodiment has 
a hollow inner cylindrical shaft 64 with a ninety degree elbow shape in 
accordance with the shape of the body 62 of the seal 60. A self-sealing 
air valve 66 is positioned in a top portion of the seal 60 in the center 
of the shaft 64. A cylindrical projection 68 extends from the lower 
portion of the body 62 at the opening of the inner shaft 64 for providing 
a passage for air flow, injected at the top in the air valve 66, to a 
water line. 
This invention has been disclosed in terms of certain embodiments. It will 
be apparent that many modifications can be made to the disclosed apparatus 
without departing from the invention. Therefore, it is the intent of the 
appended claims to cover all such variations and modifications as come 
within the true spirit and scope of this invention.