DD234293B1 - METHOD FOR SELF-CLEANING A SYSTEM FOR REMOVING SOLID-LOADED FLUID SAMPLES FROM PRESSURE TANKS - Google Patents

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a method for the removal of liquid samples from pipelines, containers u.a. Pressure systems, whose media are characterized by a solids loading, high temperature and high pressure, for the primary purpose of determining physico-chemical parameters. It is Z. B. suitable for the removal of waste liquor samples from Zellstoffkochern or other systems with solids-laden medium in the chemical industry.

Characteristic of the known technical solutions

The removal of representative liquid samples from pressurized, solids-laden systems is an unconditional prerequisite for the reproducible measurement of physico-chemical characteristics or represents the limiting factor for the meaningfulness of the analysis values. With increasing use of automatic measurement and analysis, the demands on a corresponding conditioning of the sample increase continue on

 The requirements are usually: normal temperature

normal pressure

Solid-freedom

The known technical solutions are characterized in that the sampling via a flash valve, a single or multi-stage filter and - if necessary - via a cooler.

The removal process itself can be done manually or programmatically, continuously or discreetly. The inevitable dislocation of the filter unit (s) is counteracted by hydromechanical considerations, such as centrally arranged introduction of a filter cartridge in a tangentially flowed annular chamber, or by forced backwashing with a higher pressure auxiliary medium.

The disadvantages of these technical solutions are described in the literature and also well known in practice. They usually limit the on-line use of existing measuring and analysis technology or do not guarantee the reproducibility of the measurement of physico-chemical parameters. The disadvantage of systems without forced backwashing is the high evaluation effort and the high failure rate. In system solutions with forced backwashing a high installation effort must be driven, with the introduction of a process-external flushing medium in the reaction system is often associated with unfavorable effects on the process control, the sample quality and thus on the accuracy of analysis.

Object of the invention

The aim of the invention is to develop a method which allows a representative sampling of solids laden media which are under high temperature and high pressure.

The process should be characterized by high reliability, ease of maintenance and low installation costs.

Explanation of the essence of the invention

The invention has for its object to develop a method which allows the removal of liquid samples which have a solids loading and are under pressure and temperature, without any impairment of the measurement result or the apparatus by solids or gas bubbles occurs during the actual measurement.

The system should be designed to be self-cleaning, ensure complete separation of the solid content, have an alarm for malfunctions, include the principle of maintenance and repair friendliness and have a high reliability.

This object is achieved in that a quasi-continuous, intermittent relaxation process for a freely selectable sample amount is initiated using the system-specific system pressure on coarse filtration and a suitable expansion valve, during which a self-cleaning of the expansion system takes place as follows:

In the event of a sudden full opening of the expansion valve, the medium flows through the sampling system at high speed as a result of the system pressure and is introduced tangentially into a collecting vessel, wherein coarse-grained solids are retained on a coarse filter and the fines of the last sampling cycle settled in the system are rinsed out. In sudden closure of the expansion valve, a positive pressure is generated in a branching off before the expansion valve Windkessel due to the inertia of the liquid, which leads to a coarse filter cleaning backflow.

Fines that pass through the coarse filter are separated by sedimentation and fine filtration in the pressureless collecting vessel.

The advantages of the proposed solution are that in the maintenance-friendly printing system only a separation of coarse matter takes place, the backwashing of the coarse filter cartridge without auxiliary medium is realized by the principle of hydro-pneumatic shock, the most maintenance-consuming separation of fines in the low-maintenance pressure-free collecting vessel coupled Sedimentation and filtration is laid as well as by measuring the temperature in the collecting vessel an effective alarm for disturbances in the overall system is available.

· Ausführungsbeiqri! The invention will be explained in more detail with reference to the following embodiment. The overall system has been illustrated illustratively for this purpose in FIG. The medium 3 passes through the system-specific pressure via a sampling valve 4 in a sieve pot 6 with Coarse Filter Cartridge 7. Another compound medium-Siebtopf is mounted so that when opening the valve 5 by utilizing a

system-immanent pressure drop (eg, valve, pipe bend, etc.) will force circulation of the medium through the sieve well.

The filter cartridge 7 is designed so that a deposition of the coarse material takes place. The cartridge is interchangeable, shape and Sieve width can be adapted to the character of the medium. The medium is supplied from the filter cartridge via sampling lines 11, cooler 8 to an expansion valve 10. This Valve separates the high-pressure side 1 of the entire system from the normal pressure side 2. Before the expansion valve 10, a windkettle 9 is attached. At full opening of the valve 10, the medium flows with

High speed through the sampling lines, the system cleans of deposits and is introduced into a collecting vessel 13. At sudden closure of the valve 10 takes place due to the inertia of the medium, a pressure increase in

Windkessel 9 upgrades that far exceed the actual system pressure. By relaxing this overpressure to system pressure, a backflow of the medium takes place in the direction of the sieve pot. 6 As a result, a flushing of the filter cartridge 7 is achieved. The expansion valve 10 is coupled to a timing which the opening and closing cycles of the valve 10 -

according to the desired sample quantity - realized.

The introduction of the sample medium into the collecting vessel 13 is tangential to the desired sedimentation effect

to reinforce the centrically mounted fine filter cartridge.

In the collecting vessel there is a sedimentation zone 16 for fines, a fine filter cartridge 15 and a temperature measurement The size of the sedimentation zone can by the corresponding height adjustment of the fine filter cartridge 15 and the vessel

attached siphon 17 vary and so adapt to the media character.

The sampling cycles by the timing controller 12 are selected so that over the fine filter cartridge 15 constantly a current

completely cleaned sample 18 can be fed to the evaluation unit.

The temperature measurement 14 in the vessel provides an indication of disturbances (e.g., failure of the radiator, blockages in the system

o. Ä.) and is used for alerting.

Claims (1)

Claim: Method for self-cleaning a system for removing solids-laden liquid samples from pressure vessels, characterized in that by rapid, jerky closing of the expansion valve (10) is carried out a compression of the air volume and the subsequent expansion of the air volume causes a backflow and thus self-cleaning of the sampling system.