COOLANT DISTRIBUTION FOR TOOL COOLING

DISTRIBUTION DE REFRIGERANT POUR LE REFROIDISSEMENT D'UN OUTIL

English Abstract

The invention relates to a cooling system for cooling a tool via cooling sites
(6), these being composed of a
capilla-ry tube (64) associated with a supply pathway and of an expansion
space (65) which is associated with a return pathway (41) and
into which the capillary tube (64) leads, so that a coolant conducted in
liquid form to the cooling sites (6) evaporates and is
con-ducted away in the form of gas. A distributor block (1, 11), which can be
connected to a coolant source and to a coolant sink, and
into which coolant channels (3,31,4,41) have been moulded in at least one
plane, has been designed so that it can be flanged onto
a tool.

French Abstract

L'invention concerne un système de refroidissement d'outil grâce à des emplacements froids (6) qui consistent en un tube capillaire (64) communiquant avec une ligne d'amenée et en une chambre d'expansion (65) communiquant avec une ligne de retour (41), dans laquelle débouche le tube capillaire, de telle sorte qu'un agent réfrigérant amené liquide aux emplacements froids (6) s'évapore et qu'il soit évacué sous forme de gaz. Un bloc de distribution (1, 11) pouvant être raccordé à une source et à un puits d'agent réfrigérant comporte des canaux d'agent réfrigérant (3, 31, 4, 41) pratiqués dans au moins un plan et est configuré pour pouvoir être bridé sur un outil.

Claims

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What is claimed is:
1. Coolant distribution system for the cooling of a tool through cooling
points (6)
that consists of a capillary tube (64) connected to a feeding loop (31) and an
expansion chamber (65) connected to a return loop (41) into which the outlet
of the capillary tube (94) opens so that a coolant conveyed in a liquid state
to
the cooling points (6) evaporates and is drawn off as a gas, characterized by
the fact that a hermetically sealed distribution block (1, 11) attachable to a
coolant source and a coolant sump is fitted with coolant channels (3, 31, 4,
41)
carved out in at least one plane and conformed to be attachable to a tool by a
flange, the coolant channels (3, 31, 4, 41) are conformed as feeding loops (3,
31) branching out to the cooling points (6) and as return loops (41) leaving
the
cooling points (6) to be joined in a collective conduit (4), the coolant feed
occurs from the coolant source to the feeding loops (3, 31) through a first
hose
(321) attached to an inlet conformed as a hose coupling (32) and at least one
magnetic switching unit (2) mounted after the inlet, and the coolant discharge
occurs from the collective return conduit (4) through a second hose (421) to
the coolant sump, where the outlet of the collective return conduit (4) is
conformed as a hose coupling (42) to which the second hose (421) is
attached.
2. Coolant distribution system according to claim 1, characterized by the fact
that
the coolant channels (3, 31, 4, 41) are boreholes introduced into the
distribution block (1), which lead to crossings forming connecting points
and/or
directly to the cooling points (6), and are hermetically sealed toward the
outside.
3. Coolant distribution system according to claim 1, characterized by the fact
that
the distribution block (1, 11) consists of at least two plates and the coolant
channels (3, 31, 4, 41) and are conformed in at least one plate (1) as groove-
like recesses and covered by another plate (11).
4. Coolant distribution system according to claim 1, characterized by the fact
that
the coolant channels (3, 31, 4, 41) are realized so that grove-like recesses
are

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carved out in the distribution block (1), in which the tubes conveying the
coolant are set in an irremovable manner.
5. Coolant distribution system according to any one of claims 1, 2, 3 or 4,
characterized by the fact that at least one magnetic switching unit (2) is
attached to the feeding loop (3, 31) by plug-in connectors (5).
6. Coolant distribution system according to any one of claims 1, 2, 3, 4 or 5,
characterized by the fact that the capillary tube (64) is fastened to a
connecting element (62) with an inlet and an outlet, so that the capillary
tube
(64) is tightly connected to the feeding loop (31) by the inlet, and the
expansion chamber (65) is tightly connected to the return loop (41) by the
outlet.
7. Coolant distribution system according to claim 6, characterized by the fact
that
the connecting element (62) is conformed as a supporting bushing (61) set in
the distribution block in a plug-in manner.

Description

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1
Coolant Distribution for Tool Cooling
Field of the Invention
[0001] The tools of plastic processing machines, but also of die-casting
machines,
extruders, welding machines and similar systems, where heat is to be
dissipated, are
cooled point-wise or surface-wise, as soon as the working or processing action
demands it. This draws off heat from the tool on one hand in a localized and
on the
other hand in an overall manner, so that the fastest possible cooling ensues
and
cycling times are shortened. The invention refers to such a cooling system.
Background of the Invention
[0002] German Patent Document DE 199 18 428 C1 discloses a tool cooling
process
based on carbon dioxide (CO2), designed to cool off tool areas with excess
temperatures in a localized fashion. The application range of the known
process
extends, beyond sintered porous materials, to tools made of heavy solid
materials
such as steel, aluminum, copper or other alloys. One advantage of the known
process is seen in its prevention of locally occurring temperature peaks,
which allows
reducing cycling times and molded piece defects. The known process is
characterized by the fact that pressurized carbon dioxide is, through a
feeding
system, directed to appropriate tool areas so as to cool these areas by a
localized
expansion of the carbon dioxide. The preferred tool areas are those where,
owing to
excessive tool temperatures, shiny spots or shining differences appear on the
plastic
articles, sagging points occur, deformation occasions problems or where
generally
excessive and/or tool damaging temperatures may arise. The feeding of
compressed
carbon dioxide occurs through tiny tubes or flexible hoses. Upon exiting from
these
feeding tubes, the compressed carbon dioxide expands, thus drawing off heat
from
the surrounding material. Due to the after-flowing carbon dioxide, the
expanded gas
is moved through the gap between the feeding tubes and the walls of the
expansion
chamber out of the tool, so as to enable it to escape into the atmosphere, be
captured by a special system and subsequently re-processed.
[0003] Apart from this surface-wide tool cooling, a water-jetting type cooling
is known.
The process is based on an open or closed cooling water system, where the tool
is
provided with flow channels conformed to appropriately fit the processing
conditions

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and the geometry of the work-piece and the tool. This makes it possible to
efficiently
cool the tool and the injected masses and to substantially reduce the cycling
times.
However, the use of water as a coolant can lead to calcium scaling deposits in
the
flow channels, thus lowering the cooling effect. In the worst cases, channel
plugging
and total ineffectiveness of the cooling system may occur. Another already
known
solution is described in German Patent Document DE 102 56 036 Al as a tool
cooling process and device based on the carbon dioxide expansion cooling
principle.
The known device is characterized by a plurality of boreholes, each of which
is
penetrated by a capillary tube open at its free extremity. The capillaries are
connected with a gas-feeding collection tube, and the boreholes with a gas-
collection channel for a gas return loop. However, this known solution fails
to indicate
how a large number of cooling points, which may possibly also be arranged in a
locally distributed manner, may be supplied with a coolant efficiently and
with
adequate assurance, because a simple parallel arrangement of the capillaries
cannot
satisfy these requirements.
[0004] The task thus resulting for the invention is to create a tool cooling
system of
the kind mentioned at the beginning, to be distinguished by an improved
feeding of
the coolant to the cooling points in the form of its distribution, thus
leading to
enhanced manufacturing process efficiency and better product quality.
Summary of the Invention
[0005] In accordance with the teaching of the principal claim, the task is
solved by a
coolant distribution to the cooling points that consists of a capillary tube
connected to
a feeding loop and an expansion chamber fitted with a capillary tube inlet and
connected to a return loop, so as to allow a coolant conveyed to the cooling
points in
a liquid state to evaporate and be carried off as a gas. For this purpose, a
hermetically sealed distribution block attachable to a coolant source and a
coolant
sump is fitted with coolant channels carved out in at least one plane and
formed to be
capable of being attached to a tool. The coolant channels are formed as
feeding
loops branching out to the cooling points, and as return loops connecting the
cooling
points to a collector. The coolant feeding occurs from the coolant source to
the
feeding loops through a hose which is attached to an inlet formed as a hose
coupling,
and through at least one magnetic switching unit inserted after the inlet. The
coolant

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discharge from the return loop collector occurs through a hose leading to the
coolant
sump, while the outlet of the return collector is formed as a hose coupling to
which
the hose is attached.
[0006] Advantageous improvements and configurations are given in the
subordinate
claims. The invention is characterized by embodiments of the coolant channels
that
are adaptable to various applications. In a first advantageous embodiment of
the
invention, the coolant channels are boreholes inserted into the distribution
block,
which lead to the cooling points through crossings forming junction points
and/or
directly to the cooling points, and are hermetically sealed toward the
outside. In
another advantageous embodiment of the invention, the distribution block is
made of
at least two plates and the coolant channels are formed as groove-like
recesses in at
least one plate and covered by another plate. In another advantageous
embodiment,
the coolant channels are realized so that groove-like recesses are carved out
in the
distribution block, in which the coolant carrying tubes are irremovably
disposed. The
invention is further improved by attaching at least one magnetic switching
unit to the
feeding loop, using plug-in connections. The object of the invention further
consists in
the fact that the capillary tube is fastened to a connecting element fitted
with an inlet
and outlet, so that the capillary tube is tightly connected by the inlet to
the feeding
loop, and the expansion chamber is tightly connected by the outlet to the
return loop.
The invention is advantageously implemented by shaping the connecting element
so
as to enable it to be plugged into a supporting bushing set into the
distribution block.
Brief Description of the Drawings
[0007] The characteristics of the invention will in the following be explained
in greater
detail with the aid of drawings, which show:
In Fig. 1 a preferred for of embodiment of the invention, and
In Fig. 2 a cooling point of the preferred form of embodiment.
Detailed Description
[0008] Fig. 1 illustrates a simplified top view of a plate 1 fitted with
coolant channels
3, 31, 4, 41 of a distributing block according to an aspect of the invention,
as well as
a simplified cross-section through the distribution block supplemented with a
cover

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plate 11. The plate 1 carries coolant channels 3, 31, 4, 41 milled into a
first plane so
that the feeding loops 31 are leading to all cooling points, and the return
channels
away from them. In laying out the looping system, care must be taken to
consider the
positions of the releasing pins 7 next to the cooling points, so that the
looping paths
can be provided with corresponding arcs. For ease of illustration, the coolant
channels 3, 31, 4, 41 are shown in the drawings as having corners; in practice
the
coolant channels 3, 31, 4, 41 would not include abrupt angles but rather
curves with
technically more favorable flow characteristics. The return loops 41 are
joined in a
collection conduit 4 leading to a hose coupling 42 through which, as well as
through a
hose 421 attached to the same, a coolant return flow can occur to the coolant
sump,
for instance a compressor inlet. By using an underpass 8, which may
advantageously
be formed as a stamped bridge-like element, the collection conduit 4 crosses a
feeding loop 31. The feeding loops 31 represent extensions of an inlet feeding
loop 3,
where the inlet feeding loop 3 is led to two magnetic switching units 2, each
of which
is fitted with a magnetic switch 21 from which the feeding loops 31 are
further
branched off to the cooling points 6. The magnetic switches 21 are
advantageously
inserted into the feeding loops 31 with plug-in connectors 5. The inlet
feeding loop 3
is connected to a hose coupling 32 connected to a hose 321. The hose 321 leads
to
a coolant source, for instance the outlet of a compressor. A liquid coolant
flows from
the coolant source, through the hose 321, the hose coupling 32, the inlet
feeding loop
3, the magnetic switch 21 and the feeding loops 31 to the cooling points 6,
which will
be described in detail with the aid of Fig. 2. The coolant evaporates in the
expansion
chambers 65 of the cooling points 6, becomes gaseous, and is conveyed through
the
return loops 41, the collection conduit 4, the hose coupling 42 and the hose
421 to
the coolant sump to be re-liquefied, so as to form a cooling block
hermetically sealed
by the second plate 11 and fitted with an internal coolant channel network and
an
inlet and outlet coupling, which can be connected to a plastic material
forming tool by
suitable devices.
[0009] Fig. 2 illustrates a single cooling point 6 with a capillary tube 64
flowing into an
expansion chamber 65. The capillary tube 64 is fastened to a connecting
element 62
provided with two connectors 641, 651. The first connector 641 sealingly
connects
the capillary tube 64 to the feeding loop 31. The second connector 651
sealingly
connects the expansion chamber 65 to the return loop 41. The connecting
element

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62 is fitted, through openings in the connectors 641, 651 and suitably
arranged
gasket elements 63, in a geometrically and force-induced plug-in manner, into
a
supporting bushing 61 correspondingly arranged in the plate 1.

Representative Drawing