APPARATUS FOR DETERMINING THE SMOKE DENSITY OF FLUE GASES OF GAS AND FUEL OIL

APPAREIL POUR DETERMINER LA DENSITE DES FUMEES DANS LES GAZ DE CARNEAU ENGENDRES PAR LA COMBUSTION DU GAZ ET DU MAZOUT

English Abstract

ABSTRACT OF THE DISCLOSURE:
The invention proposes an apparatus for determining the
smoke density of flue gases of gas and fuel oil, comprising a
cooled sampling thief, a cooler-drier group and a piston
pump. This apparatus improves the uniformity of the obtained
soot spot, and thereby the accuracy and repeatability of the
optical or visual determinations.

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. Apparatus for determining the smoke density of flue
gases of gas and fuel oil, characterized in that it comprises a
cooled sampling thief, a cooler-drier group and a piston
pump.
2. Apparatus according to claim 1, characterized in
that the sampling thief is cooled by a water, air or another
suitable fluid jacket.
3. Apparatus according to claim 1, characterized in
that the cooler-drier group comprises a cooler and a drier contai-
ning silica gel or another drying means with an indicator for
signaling by its colour change the exhaustion of the silica gel
or the other drying means.
4. Apparatus according to claim 1, characterized in
that the pump piston presents a double seal head.

Description

10363~6
The present i~vention relates to an apparatus for deter-
mining the smoke den~ity of flue ga~es.
Generally, the determination of the ~moke density i8
carried out by separating, from a known volume of flue gas, the
solid unburnt by filtration through a paper or the like. ~he
amount of separated solid i8 then evaluated by visual comparison
with a set of spots having a grey tonality ranging from white to
black, an increasing smoke density corresponding thereto. Such
a comparison give~ an generally accepted indication both aa to
the completeness of the combustion reaction and to the degree of
the comburent/combustible mixing in function of the air/combusti-
ble ratio. In this regard, several devices are known, which are
used for the determination of such a density.
The9e devices present, more or less, noticeable drawbacks,
among which can be mentioned the following ones: unsatisfactory
uni~ormity of the soot spot, important deterioration of some parts
of these spots and poor repeatability of the tests.
~ he subject in~ention proposes an apparatus for determi- -
ning the smoke density (thereinafter called I.F.) which improves
the uniformity of the soot spot.
~ he apparatus according to the present invention also
improves the accuracy and repeatability of determinations of the
smoke density of the distillates in general and in particular of
the fuel oils up to ~iscosities of about 18 Engler at 50C.
The ap~a ~tus according to the prese~t invention, com-
oo
prises a thcrmoota~s~ sampling thief, a cooler-drier group and a
piston pump. ~he filtering through the paper occurs at a tem-
~; perature remarkably lower than the run~ing temperature of the flue
gase~. ~hls temperature i~ kept constant by water, air or another
suitable ~luid cooling. ~he filtration is optimized by a suitable
~::
choice of the diameter of the sampling thief and of the value of
the depres ion in the sucking phase.
.:,,...
.
, ~ , ,
. . -

~()363t~6
~he in~ention will be ~ow further under~tood wlth refe-
rence to the followi~g description of an embodlment, referencea
being made to accompanying drawings.
~he apparatus according to a preferred embodiment of the
present invention comprises the following elements:
a) a sampling thief suitably cooled orthogonally
arranged with respect to the flue gas flow;
b) a tight clamping system for the filtering paper;
¢) a oooling-drying system for the sampled gase~;
d) an exhaust electric val~e for the already filtered
gases,and
e) a sucking syringe.
~ig. 1 - shows a general view of the apparatus according
to the present invention with the relevant components.
~ ~ig. 2 - shows in longitudinal section the sucking
3 ~yringe of the apparatus according to the present in~ention.
Fig. 3 - 6hows one of the two elements sealing the
piston of the syringe of fig. 2.
~ig. 4 - shows two soot spots obtained, respectively, with
the apparatus according to the present in~ention and with a prior
art apparatus.
The apparatus according to the present invention will be
described in operation.
~lue gas 2, at a known temperature, coming from ths lower
part of a stack 1 is sucked by syringe 3 through a thief 4 having
- a suitable diameter and suitably cooled by a water, air or another
suitable fluid ~acket, the inlet and outlet of which are respecti-
~ely numbered 5 and 6. ~lue gas 2 reaches,through thief 4, the
tight filtering system 7 of filtering paper 8.
` 30 ~he flue gas 29 when pas~ed through filtering paper 8,
pas~es through the cooler 9 wherein it i8 suitably cooled for
eliminating the most condensate. ~rier iO, preferably of spheri-
- 2 -
, :
. ..

1C~3~ 3 ~6
cal ~hape, contains silica gel for retaining the condensate re-
mainder with an indicator for signali~g by its colour change the
exhaustion thereof.
This group 9 - 10 prevents the rec~cle of acld substances
producing remarkable modifications of the materials constituting
the apparatus.
The flue gas 2, so cooled and dried, reaches the syringe
3, passing through a non-return valve 11, and fills the volume of
syringe 3 made a~ailable by piston 12 when being in position of
~0 aucking limit stop.
~he head of piston 12 comprises two symmetrical eleme~ts
13 having a ilanged edge for improving the ealing of syringe 3.
Several piston strokes are given for each soot spot.
In the compression phase, the flue~7s i8 evacuated from
the circuit through a valve 14. Thus, the gluc gas i8 prevented
to be rec~cled in an opposite direction this avoids an eventual
detachment o~ the soot from filtering paper ~
Fig. 4 shows two soot spot~ 15 and 16 obtained, respecti-
~ely, with a prior art apparatus having usual snd known elemen~ s
and with the same apparatus in combination with a thief ~hormoata-
~h~ according to the present invention, a cooler-drier group and
double seal piston head.
Comparing soot spot~ 15 and 16 of fig. 4 the different
distribution of the soot particles 15 presents clearly a higher
concentration in the central zone; the æpot 16, obtained with the
apparatus according to the invention, presents, on the contrary,
an uniform distribution of the particles on the whole impact zone.
~pot ~6 allow~ therefore an optical evaluation more reliable, quick
and accurate.
By a suitable choice of the size parameters and running
conditions, the smoke densities given by the apparatus according
to the present in~ention suit the ones obtained accodring to AS~M
rules.