CS207561B2 - Device for automatic determination of the smoke density - Google Patents

Abstract

1512424 Moving band filter SNAMPROGETTI SpA 20 May 1975 [21 May 1974] 21656/75 Heading BIT [Also in Division G1] A filter holder for use in smoke density measurements comprises casing 10, fixed part 11 closing one end of the casing, a mobile part comprising concentric elements 12, 13, a magnetic field producing system comprising fixed part 16, mobile part 17 and electromagnet coil 8, movement of part 17 towards elements 12, 13 temporarily clamping a filter paper 20 which is intermittently moved across aligned gas passages 11a, 12a between part 17 and the elements, and a three way electromagnetically operated valve constructed to prevent return of the gas to the filter paper, the measurement device in use including a piston pump for drawing gas to be tested through the filter holder and a controlling programming device, the piston stroke and stop time being adjustable to compensate for temperature and pressure variations, for example to ensure that the pressure drop caused by the filter paper has reached zero when readings of the blackening of the paper are taken using a scanning device (not shown).

Description

BACKGROUND OF THE INVENTION The present invention relates to an apparatus for the automatic determination of smoke density in flue gas.

The device can be used successfully to determine the amount of other pollutants, such as 'fallout' substances. Typically, the determination of the smoke density is carried out by separating the solid non-furnace from a known volume of exhaust gas obtained, for example, by means of a pump, by means of, for example, filter paper or the like.

The amount thus separated is then assessed by visual comparison, for example by means of a scale of spots of increasing gray tint running from white to black, with a corresponding smoke density. The devices known for such determinations have significant disadvantages, among which the subjectivity of sampling and reading may be mentioned, if visual, the unevenness of the sample volumes due to various factors such as gas temperature, suction speed, pause time between successive pumping, atmospheric pressure differences from place to place at different times and the impossibility of measuring very high smoke densities.

These deficiencies are overcome by a flue gas density determination apparatus comprising a programmer for controlling other components of the apparatus, a flue gas pump from a manifold coupled with a geared motor to allow for a uniform linear movement of the piston, an electrically operated valve coupled to a programmer via an automatic flue gas discharge block from the pump, a filter holder with an electrically programmable electric motor-driven geared motor mounted on the filter holder, for automatically dispensing filter paper across the flue gas path of the device, and evaluation means stored in the block for automatically removing filter paper from the device and providing a record of the smoke density in the flue gas passed through the filter.

An advantage of the device according to the invention is the stability of the volume of gases drawn in by the pump, said stability being obtained by the complex. electrical and electronic devices that are accurate in any temperature and pressure operating conditions.

Another advantage of the device of the present invention is a special filter clamping device suitable for permanent and automatic filter clamping.

In the accompanying drawings, a preferred embodiment of the invention is shown, wherein Fig. 7 is a schematic representation of the claimed device, Fig. 2 shows a cross-section of a filter clamping device suitable for the device according to the invention;

207 56 1 schematically automatic device for controlling the stroke of the sample pump piston.

The apparatus for automatically determining the smoke density in the flue gas comprises a programmer for controlling the other components of the device, a pump 3 for extracting flue gas from the duct with the piston 22 with the coupled gear motor to allow uniform piston 22 movement. with a programmer 1 through a connector (not shown) extending through a block 9 for automatic control of the flue gas discharge from the pump 3, a filter holder 6 with an electrically programmable controllable gear motor 1 mounted on the filter holder 6 for automatic dosing of filter paper stored in block 8 for automatically removing filter paper from the device and providing a record of the smoke density in the flue gas passed through the filter.

The automatic device according to the invention, provided with the above-mentioned elements, allows one or more analyzes to be performed automatically by adjustment, the number of strokes in the programmer, the time period between successive samples and the number of samples required.

Block 9 includes temperature and pressure sensing elements as well as electronic circuits suitable for correlating variations of said quantities with the total sampled volume to automatically obtain measurements with standard physical relationships.

Giant. 2 shows an exemplary embodiment of a filter fixture 6 in an apparatus according to the invention.

Said fixture comprises a non-magnetic housing 10, a fixed portion 11, a movable portion consisting of a first movable element 12 and a second movable element 13 which are different from each other, the guide elements 15 prevent the movable elements 12 and 13 from rotating, comprising a movable portion 17 and a stationary portion 16 and a spring 18 suitable for opening the magnetic circuit.

The arrangement, as shown in the drawing, permits constant pressure clamping of filter paper movable on track 19 (see FIG. 3), the clamping having a uniform effect on the sealing of the annular zone and causing no tension and slippage, as occurs with filter holders of known devices. Electromagnetic control allows further operation automatically.

Giant. 4 illustrates schematically a three-way electric valve 20 effecting suction of gases through the filter or discharge of gases from the interior of the pump out to prevent damages derived from the return gases on the filter paper, pump body 21 following the three-way electric valve; , a piston shifting handle 24, a fixed stop 25 with the pump closed, and a movable stop 26 (pump open) for automatically compensating for pressure and temperature changes resulting in a corresponding change in pump capacity.

The filter holder 6 further comprises elements suitable for sensing the pressure drop existing on the filter, the pressure drop varying from measurement to measurement and for some measurements depends on the blackening of the filter paper.

These elements give the programmer a finite time for the duration of the sampling. The end time indicates the time required for the pressure drop caused by the filter to drop to zero.

It is clear that the automatic end-time device allows very constant sample gas volumes to be obtained.

From the foregoing, complete automation of a series of operations is evident, and this automation requires a simple manual operation, i.e., a measurement number setting operation. The logical order and various changes are made automatically by the programmer. Reading by β-rays ultimately eliminates the subjective influence of the worker and allows accurate evaluation of spots with high density coefficient, their evaluation is impossible by optical comparison.

Furthermore, the automatic device according to the invention allows the use of suitable registration devices. or digital indicating devices with sophisticated smoke density printing devices, in which case it is possible to obtain a numerical display with valid decimal numbers directly.

Claims (5)

OBJECT OF THE INVENTION An apparatus for automatically determining the smoke density in a flue gas, characterized in that it comprises a programmer (1) for controlling the other components of the device, a pump (3) for withdrawing flue gas from the pipeline with a piston (22) with associated gear motor (2) to allow a uniform linear movement of the piston (22), electrically operated valve (5) associated with the programmer (1) via a block (9) for automatically controlling exhaust gas discharge from the pump (3), filter clamp (6) with associated gear motor (7) electrically programmable (1) and mounted on the filter holder (6) for automatically dispensing filter paper across the flue gas path of the device, and an evaluation means stored in the block (8) for automatically removing filter paper from the device and providing smoke density in the flue gas passed through the filter. Device according to claim 1, characterized in that the pump (3) is provided with a servomotor (4) controllable from a block (9) for controlling the stroke of the pump piston (22). Device according to claim 1 or 2, characterized in that the electrically controlled valve (2) is capable of commutating when the pressure drop caused by the filter paper is zero. Device according to Claims 1 to 3, characterized in that the filter holder (6) is an electromagnetically operable means for keeping the filter paper in tension but smooth, without damaging the filter paper, and a pressure gauge upstream and downstream of the filter paper. Device according to Claims 1 to 4, characterized in that the evaluation means in the block (8) is a beta-ray source.