CA1161371A - Degassing of liquid mixtures - Google Patents
Degassing of liquid mixturesInfo
- Publication number
- CA1161371A CA1161371A CA000384633A CA384633A CA1161371A CA 1161371 A CA1161371 A CA 1161371A CA 000384633 A CA000384633 A CA 000384633A CA 384633 A CA384633 A CA 384633A CA 1161371 A CA1161371 A CA 1161371A
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- Prior art keywords
- mixture
- aeration tank
- pump
- mixing
- pumping
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Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to a method of, and system for, degassing a mixture of a liquid first material, e.g. white water, and at least one second material, e.g. paper-making stock, the mixture being regeneratively pumped through cleaning means, e.g. a vortex cleaner, to an aeration tank.
The regenerative pumping may be controlled to control the sub-atmospheric pressure applied to, and the liquid level in, the aeration tank.
The invention relates to a method of, and system for, degassing a mixture of a liquid first material, e.g. white water, and at least one second material, e.g. paper-making stock, the mixture being regeneratively pumped through cleaning means, e.g. a vortex cleaner, to an aeration tank.
The regenerative pumping may be controlled to control the sub-atmospheric pressure applied to, and the liquid level in, the aeration tank.
Description
116137~
, Degassing o~ liquid mixtures Technical Field This invention relates to a method of degassing a mixture of a liquid first material, e.g. white water, and at least one second material, e.g. paper-making stock or stuff, comprising mixing the first and second materials and pumping the mixture so formed into an aeration tank via mixture cleaning means, e.g. a vortex cleaner. The invention also relates to a system for performing such a method.
Background Art During stock preparation in paper manufacture certain paper qualities require that the stock/white water mixture is degassed in an aeration or degassing tank before it is supplied to a headbox via a headbox pump. The degassing takes place by maintaining a negative or sub-atmospheric pressure in the aeration tank by the connection o~ a vacuum pump thereto, the negative pressure corresponding to the boiling point of the stock at the stock temperature in ; question and enabling air and other gases to be removed from the stock/l~hite water mixture. The mixture level in the tank is normally controlled by the provision of a spill-way in the tank or by the provision of a level regulator which influences a valve in a return conduit. The negative pressure maintained in the aeration tank is normally accom-plished by locating the tank at a high level relative toa mixing pump for mixing the stock or paper pulp with white water from a wire pit. This relatively high level of the aeration tank requires long ~upply and return conduits to be connected to the aeration tank which increases the cost of erecting the paper making plant~
The difference in pressure between that generated across the mixing pump and the negative pressure in the aeration tank must be sufficiently great to overcome the static lifting height between, for example, the levels of liquid in the wire pit and the aeration tank, and the pressure drop in filters, condui~s and vortex cleaners between the mixing pump and the aeration tank. The pressure drops across different types of vortex cleaners normally varies between 10 and 30 meters of water gauge (mwg). There are mainly two types of vortex cleaners, namely, one type which works towards a negative pressure and one type which works towards an overpressure.
Because of the negative pressure in the aeration tank, all liquid levels to which the aeration tank delivers flows must be located about 10 meters below the liquid level of the aeration tank, which is another reason for the high loca-tion of the tank. If the pressure drop across the vortex cleaners is low, which is aimed at, or such vortex cleaners are required which are designed to function towards an overpressure, this high location of the aeration tank is required to prevent stock/white water mixture from the mixing pump and rejects, i.e. dirty material, from the vortex cleaners, from flowing into the aeration tank, thus jeopar-dizing or making impossible the intended unctions The present invention aims to provide a method of, or system for, degassing mixtures of first and second mate-rials in an aeration tank in which the above-mentioned drawbac~s are substantially eliminated.
Disclosure of the Invention , According to one aspect of the invention theire is broadly claimed herein a method of degassing a mixture of a liquid first material and at least one second material, the liquid first material being initially contained in a container means, comprising the steps of withdrawing the liquid first material from the container means and mixing it with each second material to form a mixture, regenera-tively pumping the mixture through a mixture cleaning means and into an aeration tank, and maintaining the level of the mixture in the aeration tank substantially even with the level of the liquid first material in the container means .
~161371 The provision of regenerative pumping enebles the aeration tank to be at a lower level than otherwise would have been possible. Thus, when the method is applied to degassing a stock/white water mixture in a paper making process, it is possible to clean and degas the mixture with the smallest possible energy consumption, with the shortest possible length of conduits to and from the aeration tank, and with minimum costs for erection of apparatus for per-forming the degassing method. Furthermore, the overflow in the aeration tank may be eliminated by common control of the regenerative pumping into and pumping out of the aera-tion tank. This makes it possible to regulate the level as well as the negative pressure in the aeration tank.
According to another aspect, the invention as broadly claimed herein lies in a system for degassing a mixture of a liquid first material and at least one second material which incluaes a container means for containing the liquid irst material, an aeration tank, a mixture cleaning means and pumping and mixing means for mixing the liquid first material with the second material to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mixture cleaning means and the aeration tank, the regenerative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pressure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are positioned to be at substantially the same level as the top of the container means, and such that the level of liquid f irst material in the container means can be maintained sub-stantially even with the level of the mixture in the aeration tank.
According to a further aspect, the invention as broadly claimed herein lies in a system for degassing a mix-11~;1371 ture of stock and white water which includes a container means for containing the white water, an aeration tank, a mixture cleaning means, a pumping and mixing means and a headbox pump, *he pumping and mixing means helping to mix the white water and the stock to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank and the headbox pump helping to pump the degassed mixture out of the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mixture cleaning means and the aeration tank, the regenerative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pressure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are positioned to be at substantially the same level as the top of the container means, and such that the level of white water in the container means can be main-tained ~ubstantially even with the level of the mixture in the aeration tank Brief Description of Drawinqs The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-Figure 1 is a schematic view of a prior art system for degassing a mixture of stock and white water in a paper making process;
Figure 2 is a graph comparing the pressures at different parts of the prior art system shown in Figure 1 with the pressures at corresponding parts of a system accord-ing to the invention; and Figure 3 is a schematic view of a system, according to the invention, for degassing a mixture of stock and white water in a paper making process.
Descri tion of the Preferred Embodiment p Figure 1 shows a prior art system for degassing ~, ~ ,~
li613'71 a mixture of stock (i.e. paper fiber pulp) and dilution or whi1:e water in a paper making process. The system includes a m:Lxing pump l for stock, supplied via a conduit 2, and dilution or white water supplied from a wire pit 3 and/or from another source. The pump l pumps up this stock/white water mixture from level +2.6 (see the levels, given in meters, above a reference level - i.e. the bottom of the wire pit supplying the white water - in Figure l) via a valve 4 and possibly also filters (not shown) to a bank of vortex cleaners 5 and then to a degassing or aeration tank 6. The concentration of the mixture is about l % at the input to the vortex cleaners and, in the vortex cleaners, solid particles, such as sand and the like, are removed.
In those cases where shives and other agglomerated products (twin~) have to be removed, filters are positioned in the conduit - 4a -~4 ' 3'71 A ~
to the aeration tank 6. The inlet pressure of the incoming stock mixture to the vortex cleaners 5 is typically 26 mwg (meters of water gauge). Since the vortex cleaners 5 are directly connected to the aeration tank 6 with a negative pressure of 8.6 mwg, the pressure drop between the incoming and outgoing stock/white water mixture in the vortex cleaners is 34.6 mwg. This pressure difference is necessary for the vortex cleaners 5 to operate effectively whereas the negative pressure in the aeration tank facilitates the removal of -residual gases from the stock/white water mixture therein.The residual gases are removed from the tank 6 via a conduit 7 with the aid of a vacuum pump (not shown). The temperature in the tank is approximately +50C, and the level 8 of the mixture is maintained substantially constant by means of a spillway (not shown) at a level of +21.5 meters above the reference level (i.e. +12 metres above the level of white water in the water pit~.
From the tank 6, the degassed stock is pumped through a conduit 9 to a headbox (not shown) via a headbox pump (not shown), The headbox pump, the wire pit, the rejects outlet from the vortex cleaners and the outlet from the return con-- duit from the aeration tank must be located at such a level in relation to the aeration tank that the system is able to operate in view of the negative pressure prevailing in the tank. For practical reasons, the mixing pump and the headbox pump are often located at approximately the same level.
Thus the aeration tank is located at a relatively high level which involves a number of problems with tube lengths, return flows and a constructive erection of the degassing or aeration tank. Also from the point of view of energy, this known arrangement has drawbacks In Figure 3 there is shown an embodiment Or a system according to the invention for degassing a mixture of stock and white water in a paper making process. The system mixes, in a mixing pump 11, white water from a wire pit 16 with the stock supplied through conduit 15 from a machine chest.
3~1 The mixture is then passed through a vortex cleaner 12 to an aeration tank 13. The level of white water in the wire pit 16 i5 substantially the same as the level of the stock mixture in the aeration tank 1~. This permits the mixing pump 11, the vortex cleaner 12 and the tank 13 to be placed at substantially the same level (the least energy-demanding level). Between the tank 13 and the vortex cleaner 12 there is placed a regenerative pump 14, the object of which is to slow down the mixture flow to the aeration tank 13 and bring-about a suitable pressure across the vortex cleaner 12 which is mecessary for the effective functioning of the cleaner 12. The regenerative pump 14 also controls the negative pressure in the tank 13 and enables the vortex cleaner 12 to operate as intended. In particular the regenerative pump 14 enables the tank 13 to be positioned at a lower level than would otherwise be necessary to obtain the negative pressure in the aeration tank 13. Thus the aeration tank 13 is not at a high level as in the prior art system although the headbox pump 17 is positioned at a lower level (as before) in order to avoid cavitation. Numeral 18 designates a pressure filter and 19 is a headbox.
In the tank 13 a cooled baffle 20 is placed to prevent fluid from escaping from the tank 13 to a vacuum pump through a conduit 21. Thus only residual gases can pass to the vacuum pump 21.
The lengths and numbers of the supply and return con-duits connected to the aeration tank are less than in the prior art system and this reduction also leads to a reduced formation of twin, The mixture level in the tank 13 can be controlled by the regenerative pump 14. The baffle 20, as well as the other arrangements, and the regenerative pump 14 ~with energy feedback to the network) result in a considerable energy saving over the prior art system. Energy saving is also achieved by replacing the regulating valve 4 (Figure 1~ with - 1~6~37 ~ 7 a variable-speed control of the regenerative pump 14 and by maintaining the negative pressure in the tank 13 through the regenerative pump 14.
Drive members to the regenerative pump 14 may be a variable-speed controlled mo~or, which may also operate as a generator, ror example for feedback to the network, such as by means of a frequency converter. The motor may also be a dc motor, driven from the network via a rectifier (not shown).
. .
Figure 2 shows, in graph form, the pressure distribution, (see broken line) for the various parts of the system accord-ing to the invention shown in Figure 3 compared with the pressure distribution (see unbroken line) for the various parts of the prior art system shown in Figure 1. The y-axis of the graph of Figure 2 represents the pressure H in meters of water column (mwg) and the x-axis of the graph represents, in sequence, the variou8 sy8tem parts or components.
The reference pressure at the bottom of the wire pit 16 is taken to be zero (seé A) for both systems. The pressure increase after the pump 1 according to Figure 1 is about 48 mwgf whereas the pressure at the mixing pump 11 according to the invention is 38 mwg. The pressure drops across the vortex cleaners 5 and 12 are assumed to be the same in both cases.
, A certain pressure drop (see B) takes place across the conduits connecting the wire pit to the aeration tank in each system, After this there is, in the system according to the invention, a pressure drop of approximately 36.3 mwg across the vortex cleaner 12 and a further drop across the regenerative pump 14 so that the mixture as it enters the tank 13 has a negative pressure of -8.5 mwg. After this there takes place a pressure increase to the headbox pump 17.
With the prior art arrangement (see unbroken line in ~, ~
Figure 2), the pressure drops across the valve 4. The press-ure also drops because of the static lifting height require-ment (see C) and because of the required pressure drop across the vortex cleaner 5. After this a pressure increase takes place to the headbox pump 9.
The reduced energy requirement in a system according to the invention is clearly seen from the plots shown in Figure
, Degassing o~ liquid mixtures Technical Field This invention relates to a method of degassing a mixture of a liquid first material, e.g. white water, and at least one second material, e.g. paper-making stock or stuff, comprising mixing the first and second materials and pumping the mixture so formed into an aeration tank via mixture cleaning means, e.g. a vortex cleaner. The invention also relates to a system for performing such a method.
Background Art During stock preparation in paper manufacture certain paper qualities require that the stock/white water mixture is degassed in an aeration or degassing tank before it is supplied to a headbox via a headbox pump. The degassing takes place by maintaining a negative or sub-atmospheric pressure in the aeration tank by the connection o~ a vacuum pump thereto, the negative pressure corresponding to the boiling point of the stock at the stock temperature in ; question and enabling air and other gases to be removed from the stock/l~hite water mixture. The mixture level in the tank is normally controlled by the provision of a spill-way in the tank or by the provision of a level regulator which influences a valve in a return conduit. The negative pressure maintained in the aeration tank is normally accom-plished by locating the tank at a high level relative toa mixing pump for mixing the stock or paper pulp with white water from a wire pit. This relatively high level of the aeration tank requires long ~upply and return conduits to be connected to the aeration tank which increases the cost of erecting the paper making plant~
The difference in pressure between that generated across the mixing pump and the negative pressure in the aeration tank must be sufficiently great to overcome the static lifting height between, for example, the levels of liquid in the wire pit and the aeration tank, and the pressure drop in filters, condui~s and vortex cleaners between the mixing pump and the aeration tank. The pressure drops across different types of vortex cleaners normally varies between 10 and 30 meters of water gauge (mwg). There are mainly two types of vortex cleaners, namely, one type which works towards a negative pressure and one type which works towards an overpressure.
Because of the negative pressure in the aeration tank, all liquid levels to which the aeration tank delivers flows must be located about 10 meters below the liquid level of the aeration tank, which is another reason for the high loca-tion of the tank. If the pressure drop across the vortex cleaners is low, which is aimed at, or such vortex cleaners are required which are designed to function towards an overpressure, this high location of the aeration tank is required to prevent stock/white water mixture from the mixing pump and rejects, i.e. dirty material, from the vortex cleaners, from flowing into the aeration tank, thus jeopar-dizing or making impossible the intended unctions The present invention aims to provide a method of, or system for, degassing mixtures of first and second mate-rials in an aeration tank in which the above-mentioned drawbac~s are substantially eliminated.
Disclosure of the Invention , According to one aspect of the invention theire is broadly claimed herein a method of degassing a mixture of a liquid first material and at least one second material, the liquid first material being initially contained in a container means, comprising the steps of withdrawing the liquid first material from the container means and mixing it with each second material to form a mixture, regenera-tively pumping the mixture through a mixture cleaning means and into an aeration tank, and maintaining the level of the mixture in the aeration tank substantially even with the level of the liquid first material in the container means .
~161371 The provision of regenerative pumping enebles the aeration tank to be at a lower level than otherwise would have been possible. Thus, when the method is applied to degassing a stock/white water mixture in a paper making process, it is possible to clean and degas the mixture with the smallest possible energy consumption, with the shortest possible length of conduits to and from the aeration tank, and with minimum costs for erection of apparatus for per-forming the degassing method. Furthermore, the overflow in the aeration tank may be eliminated by common control of the regenerative pumping into and pumping out of the aera-tion tank. This makes it possible to regulate the level as well as the negative pressure in the aeration tank.
According to another aspect, the invention as broadly claimed herein lies in a system for degassing a mixture of a liquid first material and at least one second material which incluaes a container means for containing the liquid irst material, an aeration tank, a mixture cleaning means and pumping and mixing means for mixing the liquid first material with the second material to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mixture cleaning means and the aeration tank, the regenerative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pressure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are positioned to be at substantially the same level as the top of the container means, and such that the level of liquid f irst material in the container means can be maintained sub-stantially even with the level of the mixture in the aeration tank.
According to a further aspect, the invention as broadly claimed herein lies in a system for degassing a mix-11~;1371 ture of stock and white water which includes a container means for containing the white water, an aeration tank, a mixture cleaning means, a pumping and mixing means and a headbox pump, *he pumping and mixing means helping to mix the white water and the stock to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank and the headbox pump helping to pump the degassed mixture out of the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mixture cleaning means and the aeration tank, the regenerative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pressure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are positioned to be at substantially the same level as the top of the container means, and such that the level of white water in the container means can be main-tained ~ubstantially even with the level of the mixture in the aeration tank Brief Description of Drawinqs The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-Figure 1 is a schematic view of a prior art system for degassing a mixture of stock and white water in a paper making process;
Figure 2 is a graph comparing the pressures at different parts of the prior art system shown in Figure 1 with the pressures at corresponding parts of a system accord-ing to the invention; and Figure 3 is a schematic view of a system, according to the invention, for degassing a mixture of stock and white water in a paper making process.
Descri tion of the Preferred Embodiment p Figure 1 shows a prior art system for degassing ~, ~ ,~
li613'71 a mixture of stock (i.e. paper fiber pulp) and dilution or whi1:e water in a paper making process. The system includes a m:Lxing pump l for stock, supplied via a conduit 2, and dilution or white water supplied from a wire pit 3 and/or from another source. The pump l pumps up this stock/white water mixture from level +2.6 (see the levels, given in meters, above a reference level - i.e. the bottom of the wire pit supplying the white water - in Figure l) via a valve 4 and possibly also filters (not shown) to a bank of vortex cleaners 5 and then to a degassing or aeration tank 6. The concentration of the mixture is about l % at the input to the vortex cleaners and, in the vortex cleaners, solid particles, such as sand and the like, are removed.
In those cases where shives and other agglomerated products (twin~) have to be removed, filters are positioned in the conduit - 4a -~4 ' 3'71 A ~
to the aeration tank 6. The inlet pressure of the incoming stock mixture to the vortex cleaners 5 is typically 26 mwg (meters of water gauge). Since the vortex cleaners 5 are directly connected to the aeration tank 6 with a negative pressure of 8.6 mwg, the pressure drop between the incoming and outgoing stock/white water mixture in the vortex cleaners is 34.6 mwg. This pressure difference is necessary for the vortex cleaners 5 to operate effectively whereas the negative pressure in the aeration tank facilitates the removal of -residual gases from the stock/white water mixture therein.The residual gases are removed from the tank 6 via a conduit 7 with the aid of a vacuum pump (not shown). The temperature in the tank is approximately +50C, and the level 8 of the mixture is maintained substantially constant by means of a spillway (not shown) at a level of +21.5 meters above the reference level (i.e. +12 metres above the level of white water in the water pit~.
From the tank 6, the degassed stock is pumped through a conduit 9 to a headbox (not shown) via a headbox pump (not shown), The headbox pump, the wire pit, the rejects outlet from the vortex cleaners and the outlet from the return con-- duit from the aeration tank must be located at such a level in relation to the aeration tank that the system is able to operate in view of the negative pressure prevailing in the tank. For practical reasons, the mixing pump and the headbox pump are often located at approximately the same level.
Thus the aeration tank is located at a relatively high level which involves a number of problems with tube lengths, return flows and a constructive erection of the degassing or aeration tank. Also from the point of view of energy, this known arrangement has drawbacks In Figure 3 there is shown an embodiment Or a system according to the invention for degassing a mixture of stock and white water in a paper making process. The system mixes, in a mixing pump 11, white water from a wire pit 16 with the stock supplied through conduit 15 from a machine chest.
3~1 The mixture is then passed through a vortex cleaner 12 to an aeration tank 13. The level of white water in the wire pit 16 i5 substantially the same as the level of the stock mixture in the aeration tank 1~. This permits the mixing pump 11, the vortex cleaner 12 and the tank 13 to be placed at substantially the same level (the least energy-demanding level). Between the tank 13 and the vortex cleaner 12 there is placed a regenerative pump 14, the object of which is to slow down the mixture flow to the aeration tank 13 and bring-about a suitable pressure across the vortex cleaner 12 which is mecessary for the effective functioning of the cleaner 12. The regenerative pump 14 also controls the negative pressure in the tank 13 and enables the vortex cleaner 12 to operate as intended. In particular the regenerative pump 14 enables the tank 13 to be positioned at a lower level than would otherwise be necessary to obtain the negative pressure in the aeration tank 13. Thus the aeration tank 13 is not at a high level as in the prior art system although the headbox pump 17 is positioned at a lower level (as before) in order to avoid cavitation. Numeral 18 designates a pressure filter and 19 is a headbox.
In the tank 13 a cooled baffle 20 is placed to prevent fluid from escaping from the tank 13 to a vacuum pump through a conduit 21. Thus only residual gases can pass to the vacuum pump 21.
The lengths and numbers of the supply and return con-duits connected to the aeration tank are less than in the prior art system and this reduction also leads to a reduced formation of twin, The mixture level in the tank 13 can be controlled by the regenerative pump 14. The baffle 20, as well as the other arrangements, and the regenerative pump 14 ~with energy feedback to the network) result in a considerable energy saving over the prior art system. Energy saving is also achieved by replacing the regulating valve 4 (Figure 1~ with - 1~6~37 ~ 7 a variable-speed control of the regenerative pump 14 and by maintaining the negative pressure in the tank 13 through the regenerative pump 14.
Drive members to the regenerative pump 14 may be a variable-speed controlled mo~or, which may also operate as a generator, ror example for feedback to the network, such as by means of a frequency converter. The motor may also be a dc motor, driven from the network via a rectifier (not shown).
. .
Figure 2 shows, in graph form, the pressure distribution, (see broken line) for the various parts of the system accord-ing to the invention shown in Figure 3 compared with the pressure distribution (see unbroken line) for the various parts of the prior art system shown in Figure 1. The y-axis of the graph of Figure 2 represents the pressure H in meters of water column (mwg) and the x-axis of the graph represents, in sequence, the variou8 sy8tem parts or components.
The reference pressure at the bottom of the wire pit 16 is taken to be zero (seé A) for both systems. The pressure increase after the pump 1 according to Figure 1 is about 48 mwgf whereas the pressure at the mixing pump 11 according to the invention is 38 mwg. The pressure drops across the vortex cleaners 5 and 12 are assumed to be the same in both cases.
, A certain pressure drop (see B) takes place across the conduits connecting the wire pit to the aeration tank in each system, After this there is, in the system according to the invention, a pressure drop of approximately 36.3 mwg across the vortex cleaner 12 and a further drop across the regenerative pump 14 so that the mixture as it enters the tank 13 has a negative pressure of -8.5 mwg. After this there takes place a pressure increase to the headbox pump 17.
With the prior art arrangement (see unbroken line in ~, ~
Figure 2), the pressure drops across the valve 4. The press-ure also drops because of the static lifting height require-ment (see C) and because of the required pressure drop across the vortex cleaner 5. After this a pressure increase takes place to the headbox pump 9.
The reduced energy requirement in a system according to the invention is clearly seen from the plots shown in Figure
2. In another embodiment of a system according to the inven-tion, the aeration tank or tanks may have such a position relative to the mixing pump that the latter can simultaneously serve as a regenerative pump. In this case, the combined mixing and regenerative pump and the headbox pump may all be variable-speed controlled.
The invention can be varied in many ways within the scope of the following claims.
The invention can be varied in many ways within the scope of the following claims.
Claims (15)
1. A method of degassing a mixture of a liquid first material and at least one second material, the liquid first material being initially contained in a container means, comprising the steps of withdrawing the liquid first material from the container means and mixing it with each second material to form a mixture, regeneratively pumping the mixture through a mixture cleaning means and into an aeration tank, and maintaining the level of the mixture in the aeration tank substantially even with the level of the liquid first material in the container means.
2. The method as defined in claim 1, including the step of applying a vacuum to the aeration tank to pro-vide a subatmospheric pressure therein, the subastmospheric pressure being controlled by the amount of regenerative pumping applied to the mixture.
3. The method as defined in claim 2, wherein the vacuum applied to the aeration tank removes only residual gases therefrom.
4. In a system for degassing a mixture of a liquid first material and at least one second material which includes a container means for containing the liquid first material, an aeration tank, a mixture cleaning means and pumping and mixing means for mixing the liquid first ma-terial with the second material to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mixture cleaning means and the aeration tank, the re-generative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pres-sure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are positioned to be at substantially the same level as the top of the container means, and such that the level of liquid first material in the container means can be maintained substantially even with the level of the mixture in the aeration tank.
5. The system as defined in claim 4, wherein the mixture cleaning means comprises a vortex cleaner.
6. In a system for degassing a mixture of stock and white water which includes a container means for con-taining the white water, an aeration tank, a mixture clean-ing means, a pumping and mixing means and a headbox pump, the pumping and mixing means helping to mix the white water and the stock to form a mixture and pump the mixture through the mixture cleaning means into the aeration tank and the headbox pump helping to pump the degassed mixture out of the aeration tank, the improvement wherein the pumping and mixing means includes a regenerative pump located between the mix-ture cleaning means and the aeration tank, the regenerative pump acting to slow down the mixture flow rate through the mixture cleaning means while permitting a pressure drop thereacross, and wherein the aeration tank, the mixture cleaning means and the pumping and mixing means are posi-tioned to be at substantially the same level as the top of the container means, and such that the level of white water in the container means can be maintained substantially even with the level of the mixture in the aeration tank.
7. The system as claimed in claim 6, wherein the pumping and mixing means further comprises a mixing pump between the container means and the mixture cleaning means.
8. The system as claimed in claim 7, wherein the regenerative pump is located between the mixture cleaning means and the aeration tank.
9. The system as claimed in claim 7, wherein the regenerative pump is located between the mixture cleaning means and the mixing pump.
10. The system as claimed in claim 6, wherein the regenerative pump also acts as a mixing pump.
11. The system as claimed in claim 6, wherein the regenerative pump has drive means comprising a drive motor operable as a generator.
12. The system as claimed in claim 6, including evacuating means connected to the aeration tank and cooled baffle means located in the aeration tank so that the evacu-ating means is operative to remove only residual gases from the aeration tank.
13. The system as claimed in claim 7, wherein the headbox pump is positioned beneath the mixing pump.
14. The system as claimed in claim 10, wherein the said headbox pump is positioned beneath the said regen-erative pump.
15. The system as claimed in claim 6, wherein the mixture cleaning means comprises a vortex cleaner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384633A CA1161371A (en) | 1981-08-26 | 1981-08-26 | Degassing of liquid mixtures |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384633A CA1161371A (en) | 1981-08-26 | 1981-08-26 | Degassing of liquid mixtures |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1161371A true CA1161371A (en) | 1984-01-31 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384633A Expired CA1161371A (en) | 1981-08-26 | 1981-08-26 | Degassing of liquid mixtures |
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| Country | Link |
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| CA (1) | CA1161371A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115787336A (en) * | 2022-12-09 | 2023-03-14 | 安德里茨（中国）有限公司 | A mix thick liquid groove device and make paper and be equipped with thick liquid line for making paper be equipped with thick liquid line |
-
1981
- 1981-08-26 CA CA000384633A patent/CA1161371A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115787336A (en) * | 2022-12-09 | 2023-03-14 | 安德里茨（中国）有限公司 | A mix thick liquid groove device and make paper and be equipped with thick liquid line for making paper be equipped with thick liquid line |
| CN115787336B (en) * | 2022-12-09 | 2024-01-19 | 安德里茨（中国）有限公司 | Pulp mixing tank device for papermaking pulp preparing line and papermaking pulp preparing line |
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