GB1598904A - Method and an apparatus for cleaning molten salt baths - Google Patents
Method and an apparatus for cleaning molten salt baths Download PDFInfo
- Publication number
- GB1598904A GB1598904A GB21928/78A GB2192878A GB1598904A GB 1598904 A GB1598904 A GB 1598904A GB 21928/78 A GB21928/78 A GB 21928/78A GB 2192878 A GB2192878 A GB 2192878A GB 1598904 A GB1598904 A GB 1598904A
- Authority
- GB
- United Kingdom
- Prior art keywords
- molten salt
- salt bath
- bath
- basket
- cleaning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 150000003839 salts Chemical class 0.000 title claims abstract description 78
- 238000000034 method Methods 0.000 title claims description 43
- 238000004140 cleaning Methods 0.000 title claims description 32
- 239000000463 material Substances 0.000 claims abstract description 29
- 239000000835 fiber Substances 0.000 claims abstract description 16
- 239000011490 mineral wool Substances 0.000 claims abstract description 15
- 239000000126 substance Substances 0.000 claims abstract description 15
- 239000012535 impurity Substances 0.000 claims abstract description 13
- 239000011491 glass wool Substances 0.000 claims abstract description 11
- 239000010802 sludge Substances 0.000 claims abstract description 11
- 230000008093 supporting effect Effects 0.000 claims abstract description 8
- 239000002657 fibrous material Substances 0.000 claims description 27
- 238000001914 filtration Methods 0.000 claims description 23
- 238000005121 nitriding Methods 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 10
- 230000003749 cleanliness Effects 0.000 claims description 8
- 239000006260 foam Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 239000004745 nonwoven fabric Substances 0.000 claims description 5
- 229910001018 Cast iron Inorganic materials 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000010425 asbestos Substances 0.000 claims description 2
- 230000001680 brushing effect Effects 0.000 claims description 2
- 238000011109 contamination Methods 0.000 claims description 2
- 239000003365 glass fiber Substances 0.000 claims description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 2
- 239000011707 mineral Substances 0.000 claims description 2
- 230000009257 reactivity Effects 0.000 claims description 2
- 229910052895 riebeckite Inorganic materials 0.000 claims description 2
- 238000005272 metallurgy Methods 0.000 abstract 1
- 238000000746 purification Methods 0.000 abstract 1
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 239000011833 salt mixture Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 230000003019 stabilising effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
- B01D24/04—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being clamped between pervious fixed walls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/02—Loose filtering material, e.g. loose fibres
- B01D39/06—Inorganic material, e.g. asbestos fibres, glass beads or fibres
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/46—Salt baths
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Filtering Materials (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Filtration Of Liquid (AREA)
Abstract
The removal of harmful suspended substances and deposited sludge from the salt melt baths used in metallurgy is effected by means of inorganic fibre materials, in particular glass wool or rock wool, which are either inserted as filter aid layer into a filter screen immersed into the salt melt bath or are sprinkled on top of the bath surface and scooped off after binding of the impurities. The filter screen immersed into the salt melt bath is expediently made in the form of a basket, the fibre material representing a filter aid layer arranged between supporting and permeable surfaces forming bottom surfaces and side surfaces of the basket. This allows easy, rapid and thorough purification of the salt melt baths.
Description
(54) A METHOD AND AN APPARATUS FOR CLEANING
MOLTEN SALT BATHS
(71) We, DEUTSCHE GOLD-UND SILBER - SCHEIDEANSTALT Vormals
Roessler, a body corporate organised under the laws of Germany, of 9 Weisstrausrstrasse, 6 Frankfurt Main 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a process and an apparatus for cleaning molten salt baths used for the structural treatment and/or suuctural change of work pieces made of metallic, preferably iron-containing, materials.
Molten salt baths in the context of the present invention are melts of salts or salt mixtures for the treatment of work pieces at high temperatures, in particular for heating, annealing, hardening, artificial ageing or the like, in which the structure of metallic materials or alloys are treated in the desired manner or in which crystalline structures are changed.
In particular, such molten salts are used as so-called nitriding baths for nitriding ironcontaining materials.
Molten salt baths of the above-mentioned type, (cf. for example Hutte I, 28th edition, page 431) have a contaminating effect owing to the product inserted and the chemical reactions between the molten salt bath and the surface of the work pieces treated. They therefore have to be cleaned and regenerated regularly.
Basket-like containers which are adapted to the diameter and the depth of the salt bath can be used for cleaning such molten salt baths.
These basket-like containers are produced from supporting perforated plates and are provided with one or more fine-mesh sieves. The containers are immersed in the salt bath after a previous or simultaneous vigorous ventilation of the molten salt bath and are lowered to the bottom of it. After a certain stabilising and settling time, the baskets are removed again, coarse impurities having settled and being ready for removal.
A disadvantage of this mode of operation
is that only coarse particles with particle sizes
which correspond to the sieve perforation of
from 75 to 120 ,am or larger particles can be
removed. The finer iron-containing suspended
particles which are present in an increased
quantity in the molten salt baths used nowadays
which are poor in cyanide, are only trapped
by chance if this method is used. Since these particles subsequently preferably settle as a
very fine coating on the surface of the work
piece, the coating has to be removed by
expensive retouching for each individual
article. Another disadvantage which should
be mentioned is that the quality of the nitrided
articles is impaired by the porosity of the
bonding layer.
The removal of the sludge formed by the
impurities in the molten salt bath using sievelike ladles or scum pans has also proved unsuitable.
In addition, it is known that nitriding baths which are used for the treatment of castings or articles with forged or rolled skins or scale can be cleaned for the nitriding of other components only with a very high outlay and long precipitation periods. This applies even more, the higher the demands in the cleanliness of the articles to be nitrided and in the degree of cleanliness and the ductility of the bonding layer. The cleaning process just described must be repeated several times for this purpose, making the outlay in labour very high and causing the molten salt bath to be wasteful in production.
The cleaning of the newly-developed baths which are free from, or poor in, cyanide, and which have higher cyanate contents as well as those nitriding baths which may or may not evolve sulphur, has turned out to be even more difficult. Observation of the articles treated in the baths serves as a proof of the degree of cleanliness of such baths. Irrespective of the type of cooling means, for example vacuum, air, water, or salt melts, the work pieces treated in badly cleaned nitriding baths have a black, firmly adhering coating which upon metallographic examination, appears as a markedly porous bonding layer which is correspondingly brittle.
The difficulties described which are encountered during the cleaning of, or removal of, sludge deposits in molten salt baths by the methods known hitherto become greater, the higher the baths' demands in cleanliness. The difficulties also increase in proportion to the depth of the molten salt baths, since more particles of suspended matter deposited on the sieves can flow back into the bath with the draining salt melts if there is a prolonged path for the removal of the baskets.
An object of the present invention is to provide an effective and time-saving process for cleaning molten salt baths in which a high degree of cleanliness may be obtained in the molten salt bath without repeating the cleaning process several times and which may also be applied to deep molten salt baths.
The present invention therefore provides a process for cleaning a molten salt bath which comprises allowing an inorganic fibrous material to trap suspended material and/or settled sludge in the bath, and subsequently removing the inorganic fibrous material, together with any trapped substances, from the bath. The inorganic fibrous material is preferably glass or rock wool, and can be present loose, or in the form of mats or tangled nonwoven fabrics supported in sieves. The molten salt bath to be cleaned by this method is preferably one used for the structural treatment and/or structural change of work pieces made of metallic materials.
In one preferred embodiment of this invention, the suspended material and/or settled sludge is removed using a sieve which is immersed in, and subsequently removed from, the molten salt bath. This sieve supports an auxiliary filtering layer composed of the inorganic fibrous material; the layer being preferably from 10 to 60 mm thick, more preferably from 20 to 40 mm thick.
In another preferred embodiment, which is particularly applicable to the cleaning of a nitriding bath, the inorganic fibrous material is scattered on to the surface of the bath, and allowed to trap the substances separated at the surface, especially iron-containing foam.
The fibrous material is then skimmed off the surface, together with the trapped substances, using, for example, sieve-like ladles or scum
pans. In this embodiment, the inorganic fibrous
material is preferably loose glass or rock wool.
The present invention also provides an apparatus for removing suspended particles and settled sludge from a molten salt bath in
accordance with the present process. This apparatus comprises a sieve, in particular a basket-shaped sieve, and an auxiliary filtering layer (composed of inorganic fibrous materials) detachably mounted between two supporting perforated faces of the sieve. The two support
ing faces are preferably in the form of basket
like containers of known type. These may be
fitted into one another, the base and side faces
of the baskets being separated by a distance
corresponding to the thickness of the auxiliary
filtering layer.
The present invention allows not only the
removal of coarse impurities from a molten salt
bath (as was the only possibility hitherto),
but also the removal of the unwanted finest
suspended particles. The present invention is
especially applicable to the cleaning of nitriding
baths.
The apparatus and operating instruments
required for this purpose are inexpensive with
respect to the improvements obtained in the
quality of the molten salt bath, so that the
impurities in the molten salt bath may be
removed after each use in a small amount of
time and with relatively small costs in operating
time and production loss.
By regularly cleaning the molten salt bath,
and removing the fine suspended particles, sub
stantially better and more uniform results are
obtained in nitriding.
This may be particularly demonstrated
by comparative metallographical examination.
In particular, it has been found that the
compound zone has high ductility, that is to
say high malleability and deformability, and
demonstrates only minimum porosities.
It is also advantageous that the molten salt
baths which are used for treating cast iron
or articles with a rolled or forged skin can
be sufficiently cleaned in a single cleaning
process to allow them to be used again for
the treatment of other components with higher
demands in the cleanliness of the bonding
layer and the ductility thereof. High costs
for the molten salt baths on the one hand and
for the reprocessing and non-pollutant storage
of the contaminated molten salt baths which
have become unusable can be avoided in this
way.
The present invention will now be illustrated
in more detail with reference to an
embodiment.
The single figure illustrates one apparatus
for use in accordance with the present inven
tion for cleaning a molten salt bath. The
apparatus consists of an external basket 1
whose base and sides are produced from a
stable perforated plate, in order to impart the
necessary rigidity to the apparatus.
Several holding rods 2, preferably two or
three, are welded or suitably fixed to the outer
rim of the basket 1. The holding rods are connected at their upper end to a ring 3 in
which a hook of a trolley movably arranged
above the molten salt bath 7 may be suspended.
The basket 1 is covered on its base and the
internal surface of its sides with the auxiliary
filtering layer 4 according to the present
invention. The thickness of this auxiliary
filtering layer is from 10 to 60 mm, prefer ably from 20 to 40 mm. The layer consists of inorganic fibre materials, in particular glass wool or rock wool, or mats or tangled nonwoven fabrics. Other inorganic fibre materials may also be used, but the specified materials are preferred owing to their high temperature resistance, low chemical reactivity and price.
In any case, these fibre materials are preferred to slag wool and other mineral fibre materials, because of their chemical stability and because they are more readily and cheaply available than for example, asbestos fibres. The outer basket 1 is preferably lined with mats composed of glass fibres or rock wool. Spreaders 5 prevent the auxiliary filtering layer 4 from being compressed too strongly and prevent the inner basket 6 from being displaced in the outer basket 1. The inner basket 6 is placed in the outer basket and secured by radially arranged pins or screws 11. The furnace 9 itself is only partly shown, and thus the complete depth of the molten salt bath cannot be discerned. The molten salt bath 7 is heated in the crucible 8 by heating element 10 of the furnace.
In order to clean the molten salt bath, depending upon the degree of contamination, the crucible walls and the base of the crucible are firstly freed from adhering impurities by brushing. The cleaning apparatus just described is then immersed in the molten salt bath 7 and lowered on the holding rods 2 on to the base of the crucible. Owing to the resistance of the filter, the molten salt bath is displaced by the basket, and rises up outside the sides of the outer basket 1 and flows into the inner basket. Once the base of the crucible has been reached, the cleaning apparatus is slowly raised by the hook of the trolley hung in the ring 3 so that substantially all the molten salt bath is now filtered through the auxiliary filtering layer 4 arranged between baskets 1 and 6.
After removing the basket from the molten salt bath, it is cleaned and can then be used again. The inner basket is now taken out and the auxiliary filtering layer 4 is removed and renewed by removing the securing pins.
It is not worth preparing the auxiliary filtering layer for further use for reasons of cost.
Owing to the fibre material used, it is possible to remove very fine impurities and suspended particles from the molten salt bath.
From 300 to 600 g of fibres are used for each cleaning process, depending upon the size of the crucible. The time required for cleaning the molten salt bath is short in comparison to the known cleaning methods since the process need not be repeated and a residence time of the filter apparatus on the base of the crucible is not required for the settling of impurities.
In fact, the speed that the basket can be raised from the molten salt bath is governed by the passage of the molten salt through the filter.
The basket should be from 200 to 500 mm high, depending upon the depth of the molten salt bath and should be so adapted in cross
section to the size of the molten salt bath, that the entire molten salt bath has to flow through the filtering layer. This means that the external diameter of the basket 1 is not much smaller than the diameter of the crucible
so that as far as possible, the entire molten salt can be encompassed and cleaned in one operation.
The following method is adopted for cleaning the surface of the molten salt bath, especially a nitriding bath. Deposits rise to the surface of the molten salt bath during the nitriding process and from there form an iron-containing foam, depending upon the surface structure of the charging material
(rolled skin, cast iron skin etc.), and the preceding cleaning of the articles. These deposits can be easily removed before removing the charge by scattering loose inorganic fibre materials such as loose rock or glass wool on to the surface of the bath. The foam and the impurities which it contains settle in the
strewn fibre materials and can easily be skimmed off in this way. The cleanliness of the surface of the nitrided product is thus improved.
WHAT WE CLAIM IS:
1. A process of cleaning a molten salt bath which comprises allowing an inorganic fibrous material to trap suspended material and/or settled sludge in the bath, and subsequently removing the inorganic fibrous material, together with any trapped substances, from the bath.
2. A process as claimed in Claim 1, wherein the inorganic fibrous material is glass or rock wool.
3. A process as claimed in Claim 1 or Claim 2, comprising immersing a sieve into the bath, the sieve supporting an auxiliary filtering layer composed of inorganic fibrous material, and subsequently removing the sieve, together with any suspended material and/or settled sludge it has trapped from the bath.
4. A process as claimed in Claim 3, wherein the filtering layer is from 10 to 60 mm thick.
5. A process as claimed in Claim 4 wherein the filtering layer is from 20 to 40 mm thick.
6. A process as claimed in any of claims 3 to 5 wherein the inorganic fibrous material is in the form of a tangled non-woven fabric or a fibrous mat
7. A process as claimed in Claim 1 or Claim 2 comprising scattering the inorganic fibrous material on to the surface of a molten salt bath, allowing the fibrous material to trap substances floating at the surface, and skimming off the fibrous material, together with the trapped substances, from the surface.
8. A process as claimed in Claim 7 wherein the inorganic fibrous material is loose glass or rock wool.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (12)
1. A process of cleaning a molten salt bath which comprises allowing an inorganic fibrous material to trap suspended material and/or settled sludge in the bath, and subsequently removing the inorganic fibrous material, together with any trapped substances, from the bath.
2. A process as claimed in Claim 1, wherein the inorganic fibrous material is glass or rock wool.
3. A process as claimed in Claim 1 or Claim 2, comprising immersing a sieve into the bath, the sieve supporting an auxiliary filtering layer composed of inorganic fibrous material, and subsequently removing the sieve, together with any suspended material and/or settled sludge it has trapped from the bath.
4. A process as claimed in Claim 3, wherein the filtering layer is from 10 to 60 mm thick.
5. A process as claimed in Claim 4 wherein the filtering layer is from 20 to 40 mm thick.
6. A process as claimed in any of claims 3 to 5 wherein the inorganic fibrous material is in the form of a tangled non-woven fabric or a fibrous mat
7. A process as claimed in Claim 1 or Claim 2 comprising scattering the inorganic fibrous material on to the surface of a molten salt bath, allowing the fibrous material to trap substances floating at the surface, and skimming off the fibrous material, together with the trapped substances, from the surface.
8. A process as claimed in Claim 7 wherein the inorganic fibrous material is loose glass or rock wool.
9. A process as claimed in Claim 7 or Claim
8 wherein the substances floating at the surface of the bath form an iron-containing foam.
10. A process of cleaning a molten salt bath as claimed in Claim 1 when carried out using an apparatus which comprises a sieve and an auxiliary filtering layer which is detachably mounted between two supporting perforated faces of the sieve, the layer being composed of inorganic fibrous material capable of trapping suspended material and/or settled sludge in the bath.
11. A process as claimed in Claim 10, wherein the two supporting faces of the apparatus are baskets which may be fitted into each other, the base and the sides of the baskets being separated by a distance corresponding to the thickness of the auxiliary filtering layer.
12. A process as claimed in Claim 1 substantially as described with particular reference to the accompanying Figure.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2731167A DE2731167C3 (en) | 1977-07-09 | 1977-07-09 | Use of inorganic fiber materials for cleaning salt baths and device for using these fiber materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1598904A true GB1598904A (en) | 1981-09-23 |
Family
ID=6013600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB21928/78A Expired GB1598904A (en) | 1977-07-09 | 1978-05-24 | Method and an apparatus for cleaning molten salt baths |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5419266A (en) |
| CH (1) | CH637425A5 (en) |
| DE (1) | DE2731167C3 (en) |
| FR (1) | FR2396579A1 (en) |
| GB (1) | GB1598904A (en) |
| IT (1) | IT7868350A0 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2525491B1 (en) * | 1982-04-23 | 1988-04-29 | Stephanois Rech Mec | FILTER GROUP FOR SALT BATHS |
| DE3836939C1 (en) * | 1988-10-29 | 1989-06-15 | Degussa Ag, 6000 Frankfurt, De | |
| DE4337374C2 (en) * | 1992-11-09 | 1998-06-10 | Honda Motor Co Ltd | Device for desludging a molten salt |
| ES2138638T3 (en) * | 1994-01-13 | 2000-01-16 | Houghton Durferrit Gmbh | FILTER UNIT AND DEVICE TO UNSOLLATE SALT BATHS. |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB501176A (en) * | 1937-02-05 | 1939-02-22 | British Celanese | Improvements in or relating to the filtration of fluids |
| DE740298C (en) * | 1938-02-06 | 1943-10-16 | Carl Radix | Pulling the beginning of a wire through a lead bath |
| FR1019595A (en) * | 1946-12-10 | 1953-01-23 | Salt bath furnace more specially intended for the sudden cooling of steels | |
| US2757425A (en) * | 1952-11-18 | 1956-08-07 | Aluminium Lab Ltd | Apparatus and procedure for treatment of molten aluminum |
| DE1247361B (en) * | 1963-10-02 | 1967-08-17 | Degussa | Device for desludging of molten salts, in particular nitriding balls |
-
1977
- 1977-07-09 DE DE2731167A patent/DE2731167C3/en not_active Expired
-
1978
- 1978-05-16 FR FR7814456A patent/FR2396579A1/en active Granted
- 1978-05-24 GB GB21928/78A patent/GB1598904A/en not_active Expired
- 1978-05-29 JP JP6420378A patent/JPS5419266A/en active Pending
- 1978-06-09 IT IT7868350A patent/IT7868350A0/en unknown
- 1978-07-07 CH CH744078A patent/CH637425A5/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE2731167B2 (en) | 1980-02-28 |
| CH637425A5 (en) | 1983-07-29 |
| DE2731167C3 (en) | 1980-12-04 |
| FR2396579A1 (en) | 1979-02-02 |
| IT7868350A0 (en) | 1978-06-09 |
| JPS5419266A (en) | 1979-02-13 |
| FR2396579B1 (en) | 1983-01-28 |
| DE2731167A1 (en) | 1979-01-18 |
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