Chemical apparatus and process disinfecting – deodorizing – preser – Physical type apparatus – Means separating or dissolving a material constituent
Patent
1996-07-29
1998-08-11
McMahon, Timothy
Chemical apparatus and process disinfecting, deodorizing, preser
Physical type apparatus
Means separating or dissolving a material constituent
210330, 210335, 210499, B01D 1102
Patent
active
057924341
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a device for dissolving water-soluble, powdery polymers by means of a pipe that has an inlet to introduce the polymer solution comprising gel components and an outlet to discharge the polymer solution and which is provided with several filters. Additionally, the present invention relates to a process for eliminating gel components in a polymer solution, wherein the polymer solution is passed through filters which are arranged in tandem and have a decreasing mesh size.
DISCUSSION OF THE BACKGROUND
In aqueous solutions polymers having a high average molar mass (>5 millions) have a strong affinity for the surfaces of suspended colloids or extremely fine particles; this results in flocculation of these particles. As compared to the dissolved state, these particles can be separated from the aqueous solution in a much easier manner when they are in a flocculated state. This property of the polymers is used to improve a solid-liquid separation, e.g., of sludge, carried out, for example, by means of filtration through screen belt and chamber filter presses, or by means of centrifuges. Depending on the surface properties of the particles dispersed in the solution, nonionogenic, anionic or cationic polymer types are used.
The drainage of paper suspensions is also a significant field of application. In these applications it is important to use polymer solutions having a very low gel content; otherwise the papers' resistance to tearing (break of paper in the paper machine) will be deteriorated because the gel particles form undesired irregularities in the paper structure. Additionally, an increased gel content in such aqueous polymer solutions results in a deteriorated activity of the polymer solution since the polymers contained in the gel particles are not effective. In any case, the application possibilities of these polymer solutions are impaired by gel particles.
The polymers are used as dilute aqueous solution, with the concentration of the polymers amounting to <3% by weight. To prepare the aqueous solutions, the required polymer quantity is added to the water under stirring and dispersed in the solution. A maturing time of about 1 to 2 hours is necessary until the polymers dissolve completely; during this time moderate stirring is continued. However, even after the maturing time, the aqueous polymer solutions still contain gel components comprising undissolved polymers.
In order to obtain polymer solutions which are free from gels to the highest possible extent, several shearing systems are known from the prior art. However, in addition to a clear gel reduction, they result also in an undesired viscosity decrease of a polymer solution.
US-PS 4,705,640 describes a process according to which solutions of uncrosslinked polymers are sheared. In this connection, a viscosity drop is observed which is attributed to a polymer degradation going along with an increase in the ionic activity. For this reason, said shearing process can only be used for very high-molecular or cross-linked polymers, since low-molecular polymers have poor application properties owing to the polymer decomposition caused by said shearing process.
US-PS 30 21 269 and DE-OS 27 33 852 describe processes wherein intense shearing results in a gel reduction, however, also causes a mechanical decomposition of the polymers.
EP-PS 0 201 237 describes a shearing process wherein the gel content can be reduced by means of agitators constructed like large domestic mixers rotating at a speed of at least 2000 rpm. In this process as well, mechanical decomposition of the polymers takes place.
EP-PS 0 238 723 describes a process wherein polymer gel can be dissolved by means of a high-slicing shear using a heavy-duty cutting tool, without underlying a molecular degradation. This process uses a very complicated cylindrical arrangement of radially aligned knives positioned to form a vane having radial discharge spaces between the knives. Furthermore, aggregates are add
REFERENCES:
patent: 2312639 (1943-03-01), Gronemeyer
patent: 5085773 (1992-02-01), Danowski
patent: 5185086 (1993-02-01), Kaali et al.
patent: 5221483 (1993-06-01), Glenn et al.
patent: 5399265 (1995-03-01), Nehls
patent: 5417859 (1995-05-01), Bakula
patent: 5417906 (1995-05-01), Chiodo
patent: 5589081 (1996-12-01), Harris
Ferlings Friedhelm
Fischer Werner
Gunther Uwe
Hartan Hans-Georg
McMahon Timothy
Stockhausen GmbH & Co. KG
LandOfFree
Device and a process for dissolving water-soluble powdery polyme does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and a process for dissolving water-soluble powdery polyme, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and a process for dissolving water-soluble powdery polyme will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-386270