Metal casting unit

A casting unit 6 consists of a monolithic body which is annular in shape and has an annular flange 72 outturned about the axis and monolithically outstanding on the body at the outer periphery, a set of lugs 110 angularly spaced about the axis on the lower end portion of the body and monolithically outstanding in the aperture, and a circumferential groove 114 about the outer periphery of the body in the upper end portion, with mullions 20 monolithically upstanding therein, adjacent the outer periphery of the groove, to form ports 112.The groove is interconnected with the cavity 108 in the lower end portion of the body at the aperture; and passages, 126, 140, a graphite ring 16, and whatever else is required, are added to complete the unit 6 before it is supported in an aperture in a metal casting table 2, having liquid coolant discharge means 14 circumposed thereabout and a stool to support molten metal after being mated with the lugs. Where the liquid coolant discharge means take the form of a liquid coolant box, the housing 22, 24 of which defines the table, and the casting unit is upwardly inserted in the box, at an aperture 26 in the bottom, and abutted with the top of the chamber 14, a device 17 is provided for sensing leakage between the casting unit and the top of the chamber. The leakage is discharged in a passage 140 passing through one of the mullions to the bottom of the casting unit.

TECHNICAL FIELD 
This invention relates to the casting of molten metal, and in particular, 
to the casting of molten metal in an apparatus of the type wherein an 
annular metal casting unit is supported in an aperture in a casting table 
to form an open ended metal casting station thereon through which the 
molten metal to be cast is poured along a vertical axis of the table and 
cast into a molten metal body, and wherein during the casting procedure, 
the casting station has a stool operatively disposed therebelow on the 
axis of the table to telescopically engage with the bottom of the casting 
unit at a stage preliminary to the casting operation, and then in the 
operation itself, to provide a relatively retractable support for the 
molten metal body as it progressively emerges from the unit and elongates 
along the axis of the table, and wherein moreover, the metal casting unit 
has an opening formed therein about the molten metal body, and means 
formed thereabout in the apparatus for discharging liquid coolant through 
the opening to direct cool the molten metal body as it emerges from the 
unit and elongates along the axis of the table. 
BACKGROUND ART 
Apparatus of this type are widely used in the metal casting industry, and 
commonly comprise a plurality of metal casting units, all of which are 
similar in nature but supported at separate apertures in the table on 
spaced vertical axes thereof. In some apparatus, the liquid coolant 
discharge means take the form of a separate liquid coolant jacket about 
each casting unit, and a separate liquid coolant supply for the same; 
while in other apparatus, the liquid coolant discharge means take the form 
of a liquid coolant box, the housing of which defines the table and has 
spaced top and bottom housing members therein, which in turn have pairs of 
mutually opposing top and bottom apertures therein about spaced vertical 
axes of the box for the formation of the respective casting stations 
therebetween, and a chamber in the space between the housing members for 
supplying liquid coolant to the casting units at all of the respective 
stations. In each apparatus, each casting unit comprises an annular mold 
which has a vertical axis, upper and lower ends, an aperture extending 
therethrough between the ends thereof on the mold axis, an opening 
extending therethrough between the aperture and the outer periphery of the 
mold transverse the axis, and an annular flange relatively outturned about 
the mold axis on the outer periphery of the mold. Each mold is 
telescopically inserted in the table at the respective aperture or pair of 
apertures for the same, and coaxially thereof, to form the respective 
casting station, and is abutted against the table at the flange thereof, 
to receive support from the table. Moreover, where the liquid coolant 
discharge means take the form of a liquid coolant box, the housing of 
which has the aforedescribed features, the flange is commonly outstanding 
on one end portion of the mold at the outer periphery thereof, and the 
mold is telescopically inserted in the chamber of the box through the 
aperture in one of the top and bottom housing members, and abutted against 
the one housing member at the flange thereof, and against the other 
housing member about the aperture therein, so that in forming the casting 
station, the mold interfaces with the chamber at the opening in the mold 
transverse the axis thereof, for the discharge of the coolant 
therethrough. The reference in this regard to inserting the mold through 
the aperture in "one" of the housing members, takes into consideration 
that, as illustrated in U.S. Pat. No. 4,597,432, the flange may be 
outstanding on the lower end portion of the mold at the outer periphery 
thereof, and the mold may be telescopically inserted in the chamber 
through the bottom aperture of the box, and abutted against the bottom 
housing member at the flange thereof, and against the top housing member 
at the upper end portion thereof, so long as means are provided in the 
abutment interface between the upper end portion of the mold and the top 
housing member of the box, to form an annular seal between the two. In 
fact, as described in that Patent, the abutment interface commonly has a 
pair of annular seals formed thereabout in circumferentially extending 
lines of the interface which are relatively radially spaced apart from one 
another about the axis of the box and relatively offset from one another 
axially of the box, with a port interposed therebetween to intercept any 
liquid coolant which leaks from the chamber past the relatively radially 
outer seal of the interface in the direction of the axis of the box, and 
discharge the leakage coolant from the interface before the leakage 
coolant can penetrate the relatively radially inner seal thereof. 
Some apparatus of the foregoing type also employ a combination wherein each 
mold is engaged with the table in an annulus about the respective axis of 
the table, the annulus has a fluid supply connection thereacross between 
the mold and the table, and the mold has an additional opening in one end 
portion thereof, and a fluid flow passage therewithin which is 
interconnected between the fluid supply connection and the additional 
opening to transmit fluid to the additional opening from the connection 
for discharge from the mold, relatively outside thereof. In U.S. Pat. Nos. 
4,598,763 and 4,947,925, for example, the mold has an annular rabbet about 
the inner periphery thereof at the upper end thereof, the additional 
opening is formed in the axially extending wall of the rabbet, and the 
metal casting unit further comprises a ring of graphite or the like which 
is seated in the rabbet so that the fluid transmitted through the passage 
can be forced through the ring in the direction of the axis of the mold, 
to form an annulus of fluid about the molten metal body as it is cast 
within the aperture of the mold. See also U.S. Pat. Nos. 4,693,298, 
5,040,595, and 5,119,883, wherein one or more fluids are transmitted 
through the body of the mold for carrying out still other functions in 
connection with the casting operation performed by the molds described 
therein. 
DISCLOSURE OF THE INVENTION 
Heretofore, each casting unit has employed an annular mold comprising a 
composite of two or more annular components which were separately made and 
then joined together to form the mold as a whole, or perhaps to form a 
suitable transverse opening therethrough, such as an annular slot, or 
perhaps to form a flange outturned thereabout. The making of the 
individual components of the mold, and the assembly of them thereafter, 
was labor intensive and costly in material, since each component had to be 
configured to mate with the others, as well as to provide the necessary 
rabbets, holes and other recesses therein for the mold. This involved 
considerable machining and the discard of considerable material. In 
addition, the mold also had to be given sufficient body between the inside 
and outside diameters thereof, to withstand the temperature cycling it 
would undergo in the casting operation, yet not so much body as to defeat 
the limited heat transfer function of it in the apparatus. To design and 
machine the respective components to achieve all of these purposes was 
costly both in material and in labor, as indicated. 
Moreover, it has become the preferred practice to provide for discharging 
the coolant onto the molten metal body through a series of closely spaced 
holes which are arranged about the axis of the mold so that the coolant 
discharges as a corresponding series of jets which have, or are amended 
with air to have heat transfer characteristics at the surface of the 
molten metal body that differ from what the coolant would have if it were 
discharged from an annular slot. The machining of this series of holes in 
a component of the mold before it was assembled with other components, has 
required that the component have sufficient body of material to withstand 
the stress of the machining operation, and this in turn has influenced the 
design and machining of the respective components otherwise, particularly 
if the mold were to have an acceptable outside diameter. 
We have found that the mold can be made more economically, and can be given 
more substantiality of material, and more ruggedness, at minimum diameter, 
including for temperature cycling purposes, and for hole forming purposes, 
if (1) it is cast or otherwise formed as a monolithic body of mold forming 
material having a vertical axis, upper and lower ends, and an aperture 
between the ends thereof on the mold body axis; and if (2) when so formed, 
the mold body has an annular (including partannular) flange relatively 
outturned about the axis thereof, which is monolithically outstanding in 
the same material at the outer periphery of the mold body to abut the 
table when the mold body is telescopically inserted in the table at the 
respective aperture or pair of apertures for the same, coaxially thereof, 
to form the casting station; and if moreover, (3) the mold body has 
angularly spaced guide means about the axis thereof, which are 
monolithically outstanding in the same material on the lower end portion 
of the mold body in the aperture thereof, to mate with the stool in the 
stage preliminary to the casting operation, and (4) the mold body has 
angularly spaced ports about the axis thereof, which are recessed in the 
outer periphery of the mold body to interface with the liquid coolant 
discharge means, and to open into the aperture of the mold body between 
the guide means and the upper end portion of the mold body during the 
casting operation, so that the liquid coolant discharges through the ports 
into the lower end portion of the mold body to direct cool the molten 
metal as it emerges from the upper end portion of the mold body and 
elongates along the axis thereof. 
In many of the presently preferred embodiments of the invention, the mold 
body also has an annular passage therein which extends about the axis of 
the mold body in the outer peripheral portion thereof, and a series of 
openings in the inner peripheral portion thereof, which extend about the 
axis of the mold body to interconnect the passage with the aperture 
thereof between the guide means and the upper end portion of the mold 
body, and in these embodiments, the ports open into the annular passage to 
discharge the liquid coolant onto the molten metal body through the series 
of openings in the inner peripheral portion of the mold body. 
In fact, in certain of the presently preferred embodiments of the 
invention, the mold body has a first annular surface extending about the 
outer periphery thereof which interfaces with the liquid coolant discharge 
means, and second and third annular surfaces which extend about the axis 
of the mold body at the inner peripheries of the upper and lower end 
portions of the mold body, respectively, the second of which annular 
surfaces extends generally parallel to the axis of the mold body and 
defines an open ended upper cavity in the aperture thereof, having a cross 
sectional configuration in first planes transverse the axis of the mold 
body corresponding to the cross sectional configuration of the molten 
metal body to be cast therein, and the third of which annular surfaces 
defines an open ended lower cavity in the aperture of the mold body, 
having a cross sectional configuration in second planes transverse the 
axis of the mold body corresponding to the cross sectional configuration 
of the upper cavity, but greater in cross sectional area than that of the 
upper cavity in each of said second planes, so as to flare relatively 
outwardly from the axis of the mold body in the direction relatively 
toward the lower end thereof from the upper end thereof, and provide an 
annulus of open air about the molten metal body as it emerges from the 
upper cavity and elongates along the axis of the mold body in the lower 
cavity. The guide means take the form of a set of angularly spaced lugs 
which are monolithically outstanding on the third annular surface in the 
same material, to mate with the stool in the stage preliminary to the 
casting operation, and the series of ports is formed by a circumferential 
groove in the outer peripheral portion of the mold body at the first 
annular surface thereof, which has a series of mullions that are angularly 
spaced about the groove and monolithically axially upstanding therein of 
the same material, to form the ports. Preferably, the mullions are also 
radially outwardly spaced from the bottom of the groove to leave an 
annular channel about the axis of the mold body between the mullions and 
the bottom of the groove. For the reasons indicated, the mold body 
preferably also has a series of closely spaced holes in the inner 
peripheral portion thereof, which extend about the axis of the mold body 
to interconnect the channel with the lower cavity in the aperture thereof, 
for the discharge of the liquid coolant onto the molten metal body from 
the mold body. In some embodiments, the groove is formed in the upper end 
portion of the mold body, and the series of holes is sharply angled 
downwardly therefrom in the general direction of the axis of the mold 
body. 
Depending on the cross sectional configuration of the molten metal body to 
be cast in the mold body, the three annular surfaces of the mold body may 
have varying cross sectional configurations. In the apparatus described 
hereinafter with respect to the accompanying drawings, the first and 
second annular surfaces of the mold body are cylindrical, and the third 
annular surface thereof is comprised of an axially extending series of 
conical sections, the uppermost of which has the series of closely spaced 
holes opening therein, and the lowermost of which has the set of angularly 
spaced lugs monolithically outstanding thereon. 
As before, the mold body may be engaged with the table in an annulus about 
the axis of the table, the annulus may have a fluid supply connection 
thereacross between the mold body and the table, and the mold body may 
have an additional opening in one end portion thereof, and a fluid flow 
passage therewithin which is interconnected between the fluid supply 
connection and the additional opening to transmit fluid to the additional 
opening from the connection for discharge from the mold body, relatively 
outside thereof. Also, as before, the annulus may be formed about the axis 
of the table at the abutment interface between the flange and the table. 
However, in accordance with the invention, the ports in the mold body are 
defined by outer peripheral portions thereof which monolithically upstand 
in the same material between the upper and lower end portions of the mold 
body, generally axially thereof, and the fluid flow passage extends 
through one of the port defining outer peripheral portions of the mold 
body, axially thereof. 
As before, moreover, the liquid coolant discharge means may take the form 
of a liquid coolant box, the housing of which defines the table and has 
spaced top and bottom housing members therein, which in turn have a pair 
of mutually opposing top and bottom apertures therein about a vertical 
axis of the box, for the formation of the casting station therebetween, 
and a chamber in the space between the members for supplying liquid 
coolant to the casting unit at the station. In such a case, and in 
accordance with the invention, the flange is monolithically outstanding in 
the same material on one end portion of the mold body at the outer 
periphery thereof, and the mold body is telescopically inserted in the 
chamber of the box through the aperture in one of the top and bottom 
housing members, and abutted against the one housing member at the flange 
thereof, and against the other housing member about the aperture therein, 
so that in forming the casting station, the mold body interfaces with the 
chamber at the ports in the outer periphery thereof, for the discharge of 
the chamber coolant therethrough. 
Additionally, and as before, the flange may be monolithically outstanding 
in the same material on the lower end portion of the mold body at the 
outer periphery thereof, the mold body may be telescopically inserted in 
the chamber through the bottom aperture of the box, and abutted against 
the bottom housing member at the flange thereof, and against the top 
housing member at the upper end portion thereof, and the fluid supply 
connection may be formed in the abutment interface between the upper end 
portion of the mold body and the top housing member of the box, as in U.S. 
Pat. No. 4,597,432. However, in accordance with the invention, the 
additional opening is formed in the lower end portion of the mold body, 
and the abutment interface between the upper end portion of the mold body 
and the top housing member of the box has a pair of annular seals formed 
thereabout in circumferentially extending lines of the interface which are 
relatively radially spaced apart from one another about the axis of the 
box and relatively offset from one another axially of the box, with the 
fluid supply connection interposed therebetween to intercept any liquid 
coolant which leaks from the chamber past the relatively radially outer 
seal of the interface in the direction of the axis of the box, and 
discharge the leakage coolant in the direction of the additional opening 
in the lower end portion of the mold body, before the leakage coolant can 
penetrate the relatively inner seal of the interface. 
In certain of the presently preferred embodiments of the invention, the 
mold body has an annular rabbet about the outer periphery thereof at the 
upper end thereof, to form a pair of annular shoulders about the rabbet 
and the upper end of the mold body, and the top housing member of the box 
has an annular seal of elastomeric material circumposed about the axis 
thereof adjacent the top aperture therein, which is engaged with the 
annular shoulders about the rabbet and the upper end of the mold body, to 
form the pair of annular seals about the interface between the upper end 
portion of the mold body and the top housing member of the box. In 
addition, the elastomeric seal has an annular swale about the inner 
periphery thereof, at the lower end thereof, to leave an annular clearance 
between the elastomeric seal and the step of the rabbet, and the fluid 
supply connection is formed in the step of the rabbet opposite the swale 
to intercept liquid coolant which leaks across the seal between the 
elastomeric seal and the shoulder of the rabbet, before the leakage can 
penetrate the seal between the elastomeric seal and the shoulder on the 
upper end of the mold body. 
Often, in all of the embodiments of the invention wherein the liquid 
coolant discharge means take the form of a liquid coolant box, the box has 
an annular screen circumposed about the axis thereof at the outer 
periphery of the casting station, to screen the liquid coolant discharging 
through the ports of the mold body from the chamber of the box. 
Furthermore, the metal casting unit usually further comprises an annular 
baffle which is sleeved about the series of ports in the mold body and has 
a series of holes symmetrically arrayed thereabout to meter the coolant 
flow into the ports from the chamber. 
In making the annular mold for the casting unit, a monolithic body of mold 
forming material is cast or otherwise formed to have a vertical axis, 
upper and lower ends, an aperture between the ends thereof on the mold 
body axis, an annular flange which is relatively outturned about the mold 
body axis, and monolithically outstanding in the same material at the 
outer periphery of the mold body to abut the table when the mold body is 
inserted in the aperture of the table coaxially thereof, to form the 
station, and to receive support from the table, as well as angularly 
spaced guide means about the axis of the mold body, which are 
monolithically outstanding in the same material on the lower end portion 
of the mold body in the aperture thereof, to mate with the stool in the 
stage preliminary to the casting operation, and angularly spaced ports 
about the axis of the mold body, which are recessed in the outer periphery 
of the mold body to interface with the liquid coolant discharge means in 
the apparatus during the casting operation. Simultaneously, or thereafter, 
such as through a post machining operation, the ports are opened into the 
aperture of the mold body between the guide means and the upper end 
portion of the mold body, so that the liquid coolant can discharge through 
the ports to direct cool the molten metal body as it emerges from the 
upper end portion of the mold body and elongates along the axis thereof 
during the casting operation. 
Typically, the mold body is formed to have the aforementioned annular 
passage therein which extends about the axis of the mold body in the outer 
peripheral portion thereof, and the ports are opened into the aperture of 
the mold body by both forming a series of openings in the inner peripheral 
portion of the mold body, which extend about the axis of the mold body to 
interconnect the annular passage with the aperture between the guide means 
and the upper end portion of the mold body, and connecting the ports to 
the annular passage to discharge the liquid coolant onto the molten metal 
body through the series of openings in the inner peripheral portion of the 
mold body. Commonly, however, the mold body is formed with the ports 
connected to the annular passage, and then the series of openings is 
thereafter formed in the inner peripheral portion of the mold body to 
interconnect the passage with the aperture of the mold body. 
Preferably, the mold body is formed to have the three aforementioned 
annular surfaces thereon, the set of angularly spaced lugs on the third 
annular surface, and the circumferential groove in the outer peripheral 
portion of the mold body at the first annular surface, with the series of 
mullions monolithically upstanding therein. The mullions are also 
preferably formed so as to be radially outwardly spaced from the bottom of 
the groove as indicated, and the ports are opened into the aperture of the 
mold body by forming a series of closely spaced holes in the inner 
peripheral portion of the mold body, which extends about the axis of the 
mold body to interconnect the annular channel between the mullions and the 
bottom of the groove, with the lower cavity in the aperture of the mold 
body. Furthermore, the groove is preferably formed in the upper end 
portion of the mold body, and the series of holes is sharply angled 
downwardly therefrom in the general direction of the axis of the mold 
body. In the embodiment described hereinafter in reference to the 
accompanying drawings, the first and second annular surfaces are formed to 
be cylindrical, and the third is formed to comprise an axially extending 
series of conical sections, the uppermost of which has the series of 
closely spaced holes opening therein and the lowermost of which has a 
series of lugs outstanding thereon. 
In making the mold, moreover, it is also common practice to form an annular 
rabbet about the groove, at the outer peripheral edges thereof, to receive 
an annular baffle which, in forming the metal casting unit, is seated in 
the rabbet, with symmetrically spaced apertures thereabout to meter the 
coolant flow into the groove from the liquid coolant discharge means when 
the mold is inserted in the aperture of the table to form the casting 
station. 
Where the mold body is to receive a ring of graphite or the like in forming 
the metal casting unit, the method further comprises forming an annular 
rabbet about the inner periphery of the mold body, at the upper end 
thereof, to receive the ring. Where air or some other gas it to be forced 
through the ring, a fluid flow passage is formed in the mold body, which 
opens at one end into the abutment face of the flange, and at the other 
end into the rabbet at the axially extending wall thereof. In forming it, 
moreover, the passage is commonly passed through one of the mullions, 
axially of the mold body. 
Where the flange is monolithically outstanding on the lower end portion of 
the mold body at the outer periphery thereof, an annular rabbet may be 
formed about the outer periphery of the mold body at the upper end 
thereof, to provide the aforementioned pair of annular abutments about the 
axis of the mold body on the annular shoulders about the rabbet and the 
upper end of the mold body, for sealing engagement with a corresponding 
pair of annular seals on the table which are relatively radially spaced 
apart from one another about the axis of the table, and relatively offset 
from one another axially of the table, when the mold body is 
telescopically inserted in the aperture of the table coaxially thereof. 
We have also found that where, as in U.S. Pat. No. 4,597,432, an annular 
metal casting unit with an annular flange relatively outturned thereabout 
is inserted in a liquid coolant box to form an open ended metal casting 
station about a vertical axis of the box, and the box has top and bottom 
plate-like housing members, a chamber for the liquid coolant between the 
housing members, and mutually opposing top and bottom apertures in the 
members on the axis, and the annular casting unit is telescopically 
inserted in the chamber through the bottom aperture in the box, abutted 
against the bottom housing member at the flange thereof, and engaged with 
the top housing member in an annulus about the top aperture therein, and 
means are provided in the annulus to form a pair of annular seals 
thereabout in circumferentially extending lines of the annulus which are 
relatively radially spaced apart from one another about the axis of the 
box and relatively offset from one another axially of the box, the 
combination can be improved by forming an opening in the lower end portion 
of the metal casting unit, a port in the upper end portion of the casting 
unit which opens into the annulus between the annular seals formed 
thereabout, and a fluid flow passage in the metal casting unit which is 
interconnected between the port and the opening thereof to discharge to 
the opening, liquid coolant that leaks from the chamber past the 
relatively radially outer seal of the annulus in the direction of the axis 
of the box, before the leakage coolant can penetrate the relatively 
radially inner seal of the annulus. This makes it possible to use that 
inner peripheral edge portion of the top housing member which defines the 
top aperture therein, as a means for forming a cover over the port, so 
that molten metal cannot penetrate the annulus and contaminate the metal 
casting unit. Refer for example, to the aforementioned embodiments of the 
apparatus where the annular mold of the casting unit had an annular rabbet 
about the outer periphery thereof at the upper end thereof, to form a pair 
of annular shoulders about the rabbet and the upper end of the casting 
unit, and the top housing member of the box had an annular seal of 
elastomeric material circumposed about the axis thereof adjacent the top 
aperture therein, which engaged with the annular shoulders about the 
rabbet and the upper end of the casting unit, to form a pair of annular 
seals about an annulus between the upper end portion of the casting unit 
and the top housing member of the box, the elastomeric seal having an 
annular swale about the inner periphery thereof, at the lower end thereof, 
to leave an annular clearance between the elastomeric seal and the step of 
the rabbet, and the fluid supply connection or port of the casting unit 
being formed in the step of the rabbet to intercept liquid coolant which 
leaked across the seal between the elastomeric seal and the shoulder of 
the rabbet, before the leakage could penetrate the seal between the 
elastomeric seal and the shoulder on the upper end of the casting unit. 
Furthermore, we have found that the combination may be improved still 
further by providing leakage coolant detection means in the casting 
station for sensing the presence of leakage coolant flow in the passage of 
the casting unit, and communicating the same to an operator of the 
apparatus. In this way, the presence of the leakage can be made known to 
the operator, so that he can correct the matter before undertaking, or 
continuing with the casting operation. 
In certain of the presently preferred embodiments of the invention, the 
leakage coolant detection means include a leakage coolant receptacle which 
is mounted on the apparatus adjacent the casting station, and has a 
transparent window therein which is exposed relatively outside of the 
apparatus for viewing by an operator thereof. The detection means also 
include means which define a shunt in the passage for sidetracking a 
portion of the leakage coolant flow to the receptacle, and indicator means 
whereby the presence of the sidetracked portion of the leakage coolant 
flow in the receptacle is made visually apparent to the operator through 
the window of the receptacle. 
Several approaches are taken in this regard. In some embodiments, the 
indicator means include means of changeable color which are interactive 
with the sidetracked portion of the leakage coolant flow to change color 
in the window of the receptacle. In certain of them, the changeable color 
means are liquid coolant soluble, to dissolve in the sidetracked portion 
of the leakage coolant when interacting with the same. 
In many embodiments, the receptacle has an axis, a bore of predetermined 
diameter with opposing ends which are disposed on the axis of the 
receptacle and relatively proximal to and remote from the shunt, 
respectively, and a relatively reduced diameter throat which is disposed 
in the relatively remote end of the bore transverse the axis of the 
receptacle and opens onto the window of the receptacle. The proximal end 
of the bore is connected with the shunt to receive the sidetracked portion 
of the leakage coolant flow, and the indicator means are disposed in the 
bore and responsive to the presence of the side tracked portion of the 
leakage coolant flow therein, to pass through the throat and appear at the 
window of the receptacle with the flow. 
Once again, the indicator means may also include means of changeable color 
which are interactive with the sidetracked portion of the leakage coolant 
flow to change color, and in addition, pass through the throat and appear 
at the window of the receptacle with the flow. Also, the changeable color 
means may be liquid coolant soluble to dissolve in the sidetracked portion 
of the flow when interacting therewith, and then flow through the throat 
with the sidetracked portion of the flow as an additive thereto. 
In some embodiments, the receptacle has a portion thereof which projects 
relatively outside the apparatus on the axis of the receptacle, with the 
window therein for viewing by the operator of the apparatus, and the 
relatively projecting portion of the receptacle has a cavity therein on 
the opposite side of the throat from the bore to receive the indicator 
means when the same passes through the throat. In one group, moreover, the 
indicator means include a signaling device which is responsive to the 
presence of the sidetracked portion of the leakage flow in the bore, to 
pass through the throat and occupy the cavity of the receptacle for 
viewing by the operator through the window thereof. 
In other embodiments, the receptacle has an end thereof which is exposed to 
the outside of the apparatus for viewing by the operator thereof, with the 
window therein on the axis of the receptacle, the throat opens to 
atmosphere at the window of the receptacle, and the indicator means 
include a signaling device which is responsive to the presence of the 
sidetracked portion of the leakage coolant flow in the bore to project 
through the throat relatively outside the end of the receptacle at the 
window, for viewing by the operator. 
In one particular group of embodiments, the indicator means include a 
signaling device which is movably disposed in the bore of the receptacle 
to pass through the throat in the direction of the window of the 
receptacle, and biasing means are interposed between it and the proximal 
end of the bore, to urge the device along the axis of the receptacle in 
the direction of the window of the receptacle when the sidetracked portion 
of the leakage coolant flow is received in the bore. However, restrainer 
means are interposed between the signaling device and the remote end of 
the bore, to restrain it from passing through the throat in the direction 
of the window of the receptacle when the bore is devoid of leakage. But 
the restrainer means are soluble in the liquid coolant to dissolve therein 
when the leakage coolant flow is received in the bore, so that the biasing 
means can displace the signaling device along the axis of the receptacle 
to the extent that the device passes through the throat in the direction 
of the window of the receptacle. 
In some embodiments of this latter group, the signaling device takes the 
form of a ball which is coated with a liquid coolant soluble material that 
operates to restrain it from passing through the throat when the bore is 
devoid of leakage coolant, but dissolves in the leakage coolant flow when 
it is received in the bore, to enable the ball to pass through the throat 
under the bias of the leakage coolant itself, and appear at the window of 
the receptacle. In other embodiments of the group, the signaling device 
takes the form of a piston which has a pin thereon that is disposed to 
project through the throat and appear at the window of the receptacle, and 
moreover, is urged by a spring caged between the piston and the proximal 
end of the bore, to pass the pin through the throat to the extent that it 
will project relatively outside the apparatus at the window of the 
receptacle. Circumposed about the pin in the bore, however, is a sleeve 
which operates to restrain the piston from passing the pin through the 
throat to that extent, but is soluble in the leakage coolant to dissolve 
and thereby allow the spring to displace the piston to the extent that the 
pin will pass through the throat and project as indicated at the window of 
the receptacle. 
One advantage of the invention when an apparatus is equipped with a leakage 
coolant detection means, is that the table may be pivotally mounted above 
the top of a casting pit, to be swung into a horizontal position over the 
pit for the casting operation, or swung up and away from the top of the 
pit to a position wherein the bottom of the table is more readily 
observable; and when the table is so mounted and swung up and away from 
the top of the pit, the various indicator means for signaling the presence 
of leakage in a casting unit, will remain perceptible to an operator of 
the apparatus, to the same extent as when the table was in the horizontal 
position on the top of the pit.

BEST MODE FOR CARRYING OUT THE INVENTION 
In referring to the drawings, it will be seen that only so much of the 
table 2 is shown as to illustrate one casting station 4 of the table, in 
that the rest of the stations are the same as that shown. Moreover, in 
FIGS. 1 and 5, only the metal casting unit 6 at that station is shown, 
inasmuch as showing the table around it does not add materially to an 
understanding of the invention. Nor is the pit shown in FIG. 2; nor the 
hot top which is commonly superimposed on the table for the dispensing of 
molten metal to the respective casting stations 6 thereof. However, the 
molten metal is dispensed at each station through a scupper depending 
within the casting unit 6 of the station, and the scupper for the 
illustrated station is shown in phantom at 8 in FIG. 2. And lastly, during 
the casting procedure, each casting station 4 has a stool cap operatively 
disposed therebelow on the vertical axis 10 of the table at that station, 
to telescopically engage with the bottom of the respective casting unit at 
a stage preliminary to the casting operation, and then in the operation 
itself, to provide a relatively retractable support for the molten metal 
body which is cast at the station, as the molten metal body progressively 
emerges from the casting unit and elongates along the axis of the station. 
But to simplify the drawings, this too is not shown in FIG. 2 or elsewhere 
in the drawings. 
By way of an overview of the casting operation itself, molten metal 
dispensed in the scupper 8, takes shape on the cap of the stool in the 
upper cavity 12 of the casting unit, and then "stands" on the cap as a 
body of molten metal which has a thin outer shell of relatively solidified 
metal therearound, and gradually assumes an ever increasingly solidified 
state itself, as the cap is relatively retracted from the table in the 
direction downwardly of the axis 10 of the station to form an elongated 
body of solid metal known as billet. Meanwhile, liquid coolant such as 
water is discharged onto the outer shell of the molten metal body by means 
14 therearound, to direct cool the body and accelerate its rate of 
solidification on the cap. Also, in accordance with U.S. Pat. Nos. 
4,598,763 and 4,947,925, each casting unit is equipped with a graphite 
ring 16 about the casting surface thereof in the cavity 12, and during the 
casting operation, air and oil are forced through the ring to form an oil 
encompassed annulus of air about the molten metal body as it is cast 
within the cavity. Additionally, bearing in mind that each casting unit is 
bottom loaded in the table, and consistent with U.S. Pat. No. 4,597,432, 
and the invention herein, provision is made for sealing the top of each 
casting unit with the top of the table in such as way that any leakage 
tending to flow inward of the axis 10 of the table from the liquid coolant 
discharge means 14, is intercepted and discharged--not at the top of the 
table, as in the Patent--but at the bottom of the table, where in 
addition, its presence is made known to an operator by a leakage detection 
device 17 mounted on the unit. The fluid transmission system for this 
latter function is seen generally at 18 in FIG. 3; and the fluid 
transmission system for the earlier mentioned function by which an oil 
encompassed annulus of gas is formed about the molten metal body as it is 
cast within the cavity 12, is seen generally at 19 in FIG. 4. Each system 
transmits the fluid to its delivery point through one or more outer 
peripheral portions 20 of the casting unit, as shall be explained more 
fully hereinafter. And the fluid transmission systems for any additional 
functions, such as those described in U.S. Pat. Nos. 4,693,298, 5,040,595, 
and 5,119,883, might also transmit the fluid in similar fashion, but 
again, to simplify the drawings, only the systems 18 and 19 are shown as 
representative of the manner in which the outer peripheral portions 20 of 
the casting unit function for this purpose. 
Referring now to more specific features of the apparatus, it will be seen 
that the liquid coolant discharge means 14 take the form of a liquid 
coolant box, the housing of which defines the table 2 and has a pair of 
spaced top and bottom housing members 22, 24 therein which are plate-like 
in nature. The plate-like housing members in turn have a pair of mutually 
opposing top and bottom apertures 26, 28 therein about the vertical axis 
10 of each casting station 4 in the box 2, for the formation of the 
respective station therebetween, and a chamber 14 in the space between the 
housing members for supplying liquid coolant such as water, to all of the 
casting units at the respective stations. The apertures 26, 28 are 
relatively larger and smaller than one another in the bottom to top 
direction of the table, and in accordance with U.S. Pat. No. 4,597,432, 
each casting unit 6 is telescopically inserted in the chamber through its 
corresponding bottom aperture 26 of the box, and is abutted against the 
bottom housing member 22 at a flange 72 thereabout, and against the top 
housing member 24 at the upper end portion thereof. Furthermore, at the 
annulus about the top aperture 28, where the upper end portion of the 
casting unit engages the top housing member 24, the top aperture has an 
annular gland 30 of elastomeric material thereabout, which forms a pair of 
annular seals with the upper end portion of the casting unit, that have a 
connection therebetween to the fluid transmission system 18, so that any 
leakage through the relatively radially outer seal is intercepted and 
discharged from the apparatus, at the bottom thereof, as shall be 
explained more fully hereinafter. This assures that the casting unit 
remains water tight across the vertical gap 32 between the housing 
members, so that water in the chamber 14 can penetrate the casting unit 
only as intended, through an annular screen 34 circumposed about the 
station at the outer periphery thereof. 
Turning again to FIGS. 3 and 4, it will be seen that the top aperture 28 of 
the box has an annular rabbet 36 about the inner peripheral edge thereof, 
and the rabbet 36 is rabbetted again at 38, and routed to a still wider 
diameter at the vertical wall thereof, so as to have a circumferential 
groove 40 thereabout which forms an annular seat for the elastomeric gland 
30 at the top of the gap 32. The bottom aperture 26 of the box has a wide 
annular rabbet 42 (FIG. 2) about the outer peripheral edge thereof, as 
well as a circumferential groove 44 (FIG. 3) about the vertical wall 
thereof, for an elastomeric O-ring 46 which acts as a bottom seal for the 
casting unit when it is mounted in the box. In addition, threaded holes 48 
are formed in the rabbet 42 of the bottom aperture, for cap screws 50 
which are used in securing the casting unit to the box. And at the inner 
peripheral edges of their respective apertures 26, 28, the top and bottom 
housing members 22, 24 are rabbetted further, at corresponding radii of 
the axis 10, to provide a pair of annular seats 52, 54 for the screen 34 
which is circumposed about the casting station. 
The screen 34 is a band of expanded metal, cut into a C-shaped 
configuration endwise thereof, so that it can be pinched together with its 
ends overlapping one another, and then released within the gap 32 between 
the apertures 26, 28, to expand into engagement with the seats 52, 54 of 
the housing members. The gland 30, on the other hand, has a continuous 
construction circumferentially thereof, and is adapted to engage 
elastically within the groove 40 at the top of the gap, and to surround 
the uppermost rabbet 38 therein. In addition, for purposes of providing 
the pair of annular seals mentioned earlier, the gland 30 is deeply 
chamfered and contoured at the inner peripheral edge of its lower end, so 
that the corner at that end has an annular swale 56 therein, which in turn 
has rounded crests 58, 60 (FIG. 4) at the upper and lower ends thereof, 
respectively. These crests function as a pair of annular seals which are 
both radially and axially spaced apart from one another, in accordance 
with U.S. Pat. No. 4,597,432, so that leakage past the relatively radially 
outer seal 60, can be intercepted and discharged within the system 18, as 
shall be explained more fully hereinafter. 
Turning now to the casting unit 6, it will be seen that it comprises an 
annular mold 62, a refractory top ring 64 which is seated on the mold, and 
a retainer ring 66 which is threaded within the mold, and about the top 
ring to clamp the top ring to the mold. The casting unit also comprises 
the graphite ring 16 and the leakage detection device 17 mentioned 
earlier, and in addition, an annular baffle 68 which is engaged about the 
waist of the annular mold, to meter the coolant flow therethrough, as 
shall be explained more fully hereinafter. 
The mold 62 itself is formed as a monolithic body of mold forming material 
such as metal, with a relatively outturned, part truncated flange 72 about 
the outer periphery thereof, which is monolithically outstanding on the 
lower end portion of the mold. Above the flange, the mold is adapted at 
the outer peripheral outline 70 thereof, to be telescopically insertable 
in the aperture 26 at the bottom of the box, and adapted lengthwise of the 
axis 10 thereof, to be abutted against the gland 30 at the top of the box 
when the flange 72 of the mold abuts against the rabbet 42 in the bottom 
housing member 22 of the box. Meanwhile, the O-ring 36 in the groove 46 
provides a seal at the bottom of the box, and threaded holes 74 in the 
flange, adapted to register with the holes 48 in the box, enable the cap 
screws 50 to be used in securing the mold to the box. 
The mold is also adapted so that when inserted in the box, that portion of 
it which occupies the gap 32, is slightly reduced in diameter at the outer 
peripheral surface 76 thereof, for more ready engagement with the crest 60 
of the gland, and moreover, is ported at the surface 76 to provide for 
liquid coolant flow through the mold for the cooling function mentioned 
earlier. First, however, before describing these features, it will be seen 
that at its upper end, the mold has an annular rabbet 78 about the outer 
periphery thereof, which is rounded at the outside shoulder thereof, and 
less so at the inside shoulder, to provide abutments 80, 82 for engagement 
with the crests 58, 60 of the gland. In addition, the instep 84 (FIG. 2) 
of the rabbet opposes the swale 56 in the gland, so that when they are 
abutted, an annular clearance is formed between the two, the purposes for 
which will be explained more fully in connection with the system 18. 
At the inner peripheral edge of its upper end, the mold is more widely and 
deeply rabbetted, and the rabbet 86 has threading 88 about the vertical 
wall thereof, and a slight unthreaded neck 90 about the top of the 
threading, to accommodate the top ring 64 and the retainer ring 66 
assembly of the casting unit. The neck 90 also provides a clearance 
between the ring assembly and the rabbet 38 in the top housing member, to 
accommodate a further retainer means (not shown) for the scupper. 
At the inner periphery of the rabbet 86, the mold is rabbetted again at 92, 
to form an annular step for a further O-ring 94 inserted between the mold 
and the refractory top ring, and that rabbet is rabbetted again at 96, and 
more deeply, to form an annular shoulder for the graphite ring. The 
graphite ring 16 is cylindrical, and at the inner peripheral surface 
thereof, is substantially equal in diameter to the inner peripheral 
surface 100 of the upper end portion of the mold. Both are sized at their 
inner peripheral surfaces, moreover, to correspond to the cross sectional 
area of the billet to be cast at the station, and together, they define 
the casting surface of the mold, at the upper cavity 12 therewithin. 
Below the upper cavity 12, and at its inner periphery, the mold has three 
axially successive conical surfaces 102, 104, 106, which define an open 
ended lower cavity 108 in the mold, having a cross sectional configuration 
transverse the axis 10 of the mold, corresponding to that of the upper 
cavity 12, but greater in cross sectional area than that of the upper 
cavity so as to flare relatively outwardly from the axis in the direction 
relatively toward the lower end of the mold from the upper end thereof. 
This flare provides an annular clearance about the molten metal body as it 
emerges from the upper cavity of the mold, and as shall be explained, 
coolant water is discharged onto the molten metal body in this clearance 
to direct cool the body as it elongates along the axis of the mold. 
The coolant is discharged at the uppermost 102 of the three surfaces, which 
forms a shallow dome-like mantle above the clearance, at a level adjacent 
that at which the molten metal body emerges from the upper cavity. 
However, as indicated earlier, the body "stands" on a stool cap as it 
elongates along the axis 10, and in a stage preliminary to the casting 
station, the stool cap must be telescopically engaged with the mold to 
take up support of the molten metal body. Therefore, to align the upper 
cavity 12 of the mold with the cap, and vice versa, the lowermost surface 
106 of the lower cavity 108 has a set of lugs 110 monolithically 
outstanding thereon in the same material as the mold, to act as slideably 
engageable guides for the cap, and the lugs are angularly spaced about the 
axis of the mold to enable the coolant water to run between them when the 
molten metal body is first formed along the axis of the mold. 
Returning to the surface 76 at the outer periphery of the mold, it will be 
seen that the mold has a series of ports 112 therein (FIG. 5) which are 
angularly spaced about the axis 10 of the mold and disposed in the upper 
end portion of the mold, at the outer periphery thereof, to interface with 
the chamber 14 of the box. The series of ports is formed by a 
circumferential groove 114 in the surface 76 of the mold, which has a 
series of mullions 20 angularly spaced thereabout, and monolithically 
axially upstanding therein, in the same material as the mold, to form the 
ports. The mullions 20 are also radially outwardly spaced from the bottom 
of the groove to leave an annular channel 116 about the axis 10 of the 
mold, between the mullions and the bottom of the groove. To discharge the 
coolant water into the lower cavity 108 of the mold from the groove 114, 
the mold has a series of closely spaced holes 118 in the inner peripheral 
portion thereof, which extend about the axis 10 of the mold in the 
domelike surface 102 thereof, and interconnect the channel 116 with the 
lower cavity of the mold at the upper end of the clearance provided by the 
flare of the canopy 102, 104, 106 thereabout. Because of the disposition 
of the groove 114 in the upper end portion of the mold, the series of 
holes 118 is also sharply downwardly angled to the axis of the mold, to 
sharply angle the coolant discharge impinging on the surface of the molten 
metal body. Meanwhile, the orifice-like size of the holes 118, reduces the 
discharge to a corresponding series of jets which achieve a faster quench 
on the surface of the molten metal body, and lend themselves to other 
functions in the way of altering the heat transfer characteristics of the 
coolant on the surface of the metal, as explained in U.S. Pat. Nos. 
4,693,298, 5,040,595, and 5,119,883. 
The mullions 20 are also inset from the outer peripheral surface 76 of the 
mold, and the groove 114 is rabbetted at the outer peripheral edges 
thereof, to form an annular seat 120 about the mouth of the groove for the 
baffle. The baffle is adapted to snap engage in the seat, and has a series 
of symmetrically spaced holes 122 thereabout, which meter the coolant flow 
into the groove for discharge into the holes 118, and then into the 
clearance 108 about the surface of the molten metal body. 
Referring now to the fluid transmission system 19, it will be seen that the 
upper face 132 of the flange 72 forms an annulus with the rabbet 42 of the 
bottom housing member, where it abuts the same, and a fluid flow passage 
124 is shown in the mold between that annulus and the outer periphery of 
the graphite ring 16, to represent one of the two fluid transmission 
systems normally provided for forcing oil and air through the ring in the 
manner of U.S. Pat. Nos. 4,598,763 and 4,947,925. The passage 124 
comprises a vertical hole 126 which is drilled into the mold from the 
bottom end thereof, and directed axially upwardly of the mold to pass 
through one of the mullions 20 at the outer periphery thereof. The 
vertical hole 126 is then interconnected with the outer periphery of the 
graphite ring and the annulus, by a horizontal hole 128 drilled into the 
mold from the vertical wall of the rabbet 96, and an oblique hole 130 
drilled into the mold from the annulus at the flange thereof. An annular 
seal such as an O-ring (not shown) is provided at the joint 134 between 
the rabbet 42 of the bottom housing member, and the upper face 132 of the 
flange, and a plug 135 is inserted in the bottom of the vertical hole 126, 
to close the passage 124 for the supply of pressurized fluid to the system 
19 from a source 136 connected with the joint 134 through the bottom 
housing member of the box. 
The fluid transmission system 18 also operates to discharge fluid from the 
mold, relatively outside thereof, but in the sense of relieving the mold 
of unintended leakage from the chamber of the box, rather than delivering 
fluid to a surface of the mold for intentional discharge therefrom for one 
of the functions described in the aforementioned Patents. Referring again 
to FIG. 3, it will be seen that the mold has an additional opening 142 
therein, at the outer peripheral edge of the flange, and a fluid flow 
passage 138 therein which interconnects the step 84 of the rabbet 78 in 
the upper end of the mold, with the additional opening 142. The passage 
138 comprises a second vertical hole 140 which is drilled upwardly in the 
mold from the bottom thereof, first through another of the mullions 20 at 
the outer periphery of the mold, and then into the step 84 of the rabbet 
78 at the upper end of the mold. The vertical hole 140 intersects the 
additional opening 142 in the flange, and when unplugged at the bottom 
thereof, provides a discharge passage for any coolant water which leaks 
past the relatively outer seal 82, 60 between the outer abutment 60 on the 
upper end of the mold and the outer crest 82 of the elastomeric gland 30, 
before the leakage can penetrate the relatively inner seal between the 
abutment 58 of the mold and the crest 80 of the gland. However, when 
plugged at the bottom, the hole 140 provides a shunt for discharging the 
leakage at the opening 142, while a portion of the leakage is collected in 
the bottom of the hole, to signal to the operator the presence of leakage 
flow in the passage. 
Referring now to FIGS. 7-15 in conjunction with FIG. 3, it will be seen 
that the bottom of the hole 140 has a socket 146 formed therein, and an 
elongated ball equipped receptacle-type leakage detection device 17 is 
mounted in the socket to depend relatively downwardly from the bottom of 
the mold, at the lower end portion 148 thereof. The device comprises a 
thimble-like receptacle 150 made of clear plastic or the like, which is 
transparent so as to reveal the contents of anything captured in the 
interior of the exposed lower end portion 148 of the receptacle. The 
receptacle also has a neck 152 thereabout, at the lower end portion 
thereof, to provide a grip for insertion and removal of the device from 
the socket; but thereabove, the main body or shank 154 of the receptacle 
is cylindrical at the outer periphery thereof, to telescopically engage in 
the socket 146 when inserted therein. The diameter of the shank is reduced 
slightly, however, to provide a flange 156 for abutment with the bottom of 
the mold; and shortly thereabove, there is a circumferential groove 158 
about the shank, and a shallower groove 160 in the wall of the socket, to 
accommodate an elastomeric ring 162 seated in the groove 158 of the device 
and detachably engageable with the mold at the groove 160 thereof, to 
removably secure the device to the mold. 
Inside, the receptacle 150 has an elongated cylindrical bore 164 which 
extends within the exposed lower end portion 148 of the receptacle, but 
the bore is interrupted at its midsection, by a reduced diameter throat 
166 which is square in cross section, transverse the longitudinal axis of 
the bore, and sized to provide a seat for a coated indicator ball 168 
loosely received in the upper end portion of the bore. The ball 168 has a 
water soluble coating 170 about the spherical core 172 thereof, and with 
the coating thereon, the diameter of the core is such that it is held 
captive in the upper end portion of the bore by the side to side dimension 
of the throat 166, but without the coating, it is capable of passing 
through the throat between the sides thereof, such as when the coating is 
dissolved by leakage coolant in the bore from the passage 138 thereabove. 
Meanwhile, even before the coating is dissolved, the ball and throat 
define a clearance therebetween at each corner 174 of the throat, through 
which the leakage coolant can drip into the cavity 165 remaining at the 
bottom of the throat, in the exposed lower end portion 148 of the 
receptacle. 
The device 17 is positioned below the juncture 144 between the holes 140, 
142 of the passage, and therefore, receives the initial flow of leakage 
from the clearance between the rabbet 78 of the mold and the swale 56 of 
the elastomeric gland 30. During this time, before the leakage accumulates 
to the extent of spilling out the hole 142 in the flange, the coating 170 
on the ball is subjected to dissolution by the coolant, even as the 
coolant drips into the cavity 165 of the exposed lower end portion 148 of 
the receptacle. Given a coating which is color producing in the coolant, 
therefore, the water which drips into the cavity 165 will appear through 
the transparent window provided by the clear plastic construction of the 
receptacle. Ultimately, when the coolant has dissolved the coating to such 
an extent that the core 172 of the ball is free to pass through the throat 
166, then the core itself will also appear in the cavity of the receptacle 
as a solid object standing in the colored water therein. Of course, when 
the leakage rises above the level of the juncture 144, any excess leakage 
spills out the hole 142 in the flange, but prior to that time, an operator 
is likely to observe, first, the presence of the colored liquid in the 
cavity of the device, and then the core 172 itself, standing in that 
liquid as an indication of the more advanced stage to which leakage has 
occurred in the device. And as explained earlier, he can observe both of 
these stages even after the table has been tilted into an inclined 
position above the top of the pit, such as when, at a time prior to the 
casting operation, the operator has lowered the table over the pit, mated 
the stool with the lugs 110 of the respective stations, tested the table 
with pressurized coolant, and then raised the table once again for the 
viewing of it in the tilted up position thereof. 
The receptacle-type leakage detection device seen in FIGS. 16 and 17 
differs from that seen in FIGS. 7-15, in that the receptacle 176 of it has 
an open ended bore 178, the upper end 180 of which is threaded and the 
lower end 184 of which has a reduced diameter aperture 186 therein that 
opens to atmosphere and provides a "window" for the device. A piston 188 
with an elongated but reduced diameter pin 190 on the forward end 192 
thereof, is loosely received in the bore, and urged into engagement with 
the lower end 194 of the bore by a coiled spring 196 which is received in 
a socket 197 in the piston, and caged between the socket and a cap 198 
threaded into the upper end 180 of the bore. The pin 190 loosely protrudes 
within the aperture 186, meanwhile, and when the piston abuts the lower 
end 194 of the bore, under the urging of the spring 196, the nose of the 
pin actually projects through and well beyond the aperture 186 to appear 
outside the lower end 184 of the receptacle. However, the pin has a sleeve 
200 of water soluble material circumposed thereabout, between the forward 
end 192 of the piston and the lower end 194 of the bore, and the cap 198 
in the upper end 180 of the bore has an open faced spider mounted core 202 
therewithin for the spring, so that water from the juncture 144 of the 
passage 138 can pass through the cap and move along the annulus 204 about 
the piston, to attack the sleeve 200 between the piston and the lower end 
of the bore. Commonly, the water soluble material is granular and 
sufficiently water penetratable that the leakage can escape through the 
annulus 206 between the pin and the aperture 186 of the receptacle while 
the sleeve is undergoing dissolution. Again, given a color producing water 
soluble material, this leakage at the "window" 186 of the receptacle will 
be apparent to an operator of the apparatus, but ultimately, when the 
sleeve 200 has been dissolved, the bias of the spring 196 will force the 
piston against the lower end 194 of the bore and project the full length 
of the nose of the pin beyond the window, to signal the more advanced 
stage of leakage flow to the operator. 
Once again, the receptacle has a neck 208 thereabout as a grip, and an 
elastomeric O-ring 210 thereabout for interengagement between the 
receptacle and the body of the mold, at the socket 146 therein. Also, so 
that the sleeve 200 can be replenished when desired, the receptacle has a 
threaded port 212 in the neck thereof, and a flat headed screw 214 is 
threaded into the port, and countersunk below the outer periphery of the 
receptacle, for removal from the receptacle when it is desired to recharge 
the bore with a new sleeve, the piston meanwhile being retracted against 
the bias of the spring by depressing the nose of the pin 190 into the 
aperture 186 at the lower end 184 of the receptacle. 
In still another receptacle-type leakage detection device (not shown), the 
receptacle has a plain cylindrical vertical bore therein, terminating in a 
window at the bottom thereof, which is of the same diameter as that of the 
bore, and open to atmosphere, like that seen at 186 in the device of FIGS. 
16 and 17, but the window is large enough to contain a plug which is 
detachably engaged in it from a point therebelow, outside of the device, 
and is of changeable color, so as to change color to, say, bright red, 
when sensitized by exposure to liquid coolant in the bore of the 
receptacle thereabove. 
The mold may be formed as a monolithic body of mold forming material, which 
is annular in shape and has no more features than those shown in the 
dashed outline of FIG. 6. That is, the monolithic body may have upper and 
lower ends, the aperture 12, 108 between the ends thereof on the mold body 
axis 10, the annular flange 72 relatively outturned about the axis 
thereof, at the outer periphery thereof, the set of lugs 110 about the 
axis thereof on the lower end portion of the mold body, and the 
circumferential groove 114 about the outer periphery thereof in the upper 
end portion of the mold body, with the mullions 20 upstanding therein. 
Then, given this intermediate product with which to work, a machinist can 
machine the various rabbets, holes, chamfers, and the like in and from the 
monolithic body, to form the mold body seen in the remaining Figures. 
Thereafter, before anything else is added, the graphite ring can be heat 
shrunk into its seat on the shoulder 76 of the mold body; and finally, the 
remaining elements of the casting unit can be added to the mold body, to 
complete the unit. Commonly, they are added by slipping the baffle 68 
about the mold body until it snap engages in the seat 120 for the same, 
and then adding the graphite ring 16, the O-ring 94, and the top ring and 
retainer ring assembly, to the upper end of the mold body. For this 
purpose, the graphite ring has a height flush with the rabbet 86 of the 
mold body at the inner periphery thereof, so that the O-ring 94 is 
captured between the graphite ring and the mold body, at the step 92; and 
in addition, it has a rabbet 216 at the upper inner peripheral edge 
thereof, within which a corresponding rabbet 218 in the lower outer 
peripheral edge of the refractory top ring 64, can mate with the graphite 
ring. Meanwhile, the inner periphery of the top ring is sized and slightly 
conical, to engage about the bottom end portion of the scupper 8, and the 
top ring 64 and the retainer ring 66 are mitered at the opposing upper and 
lower outer peripheral and inner peripheral corners 220, 222 thereof, to 
enable the top ring to be clamped to the top of the mold body, by 
threading the retainer ring into the rabbet 86 at the upper end of the 
mold body. 
Commonly, the retainer ring 66 has a set of sockets (not shown) in the 
upper surface thereof, to receive a spanner wrench with which to thread 
the ring into the mold in this latter operation. 
When the casting unit is to be installed, the gland 30 is seated in the 
groove 40 of the top housing member, the screen 34 is inserted in the gap 
32 and then seated about the gap at the seats 52, 54 for the same, and 
then the casting unit 6 is upwardly inserted in the gap until the 
rabbetted upper end of the mold body abuts the gland at the crests 80,82 
thereof, and the flange 72 of the mold body abuts the bottom housing 
member at the rabbet 42 therein. The refractory top ring 64, meanwhile, 
engages about the scupper 8, and may have means (not shown) inserted 
therebetween to aid in forming a refractory seal between the two. 
To aid in forming a pocket for the annulus of gas formed around the molten 
metal body as it takes shape in the cavity 12 of the mold, the bottom of 
the top ring is often relieved at the outer peripheral edge portion 224 
thereof, as seen in FIG. 4. 
To aid in withdrawing the casting unit from the table, the mold is commonly 
equipped with a further circumferential groove 226 about the outer 
peripheral edge of the flange, so that a mechanical grab (not shown) can 
be employed to take a better grip on the mold in the process of 
withdrawing the unit. 
The intermediate product seen in FIG. 6 may be formed by any one of several 
conventional processes, including that of casting it in a permanent mold 
(not shown) having a heat reducible filler enclosed therewithin for the 
groove, and that of forming it by the lost foam technique which is widely 
used today in other technologies. Alternatively, the intermediate product 
may be formed by machining a block of metal or the like until it has the 
necessary character and configuration, including the groove 114 and the 
mullions 20 therein, but this is the least desirable technique, since it 
defeats many of the advantages provided by the invention.