CN205679440U - A kind of sampling system being capable of constant flow isokinetic sampling - Google Patents

Abstract

The utility model relates to a sampling system capable of realizing constant flow and constant speed sampling, comprising a sampling detection device, a speed measuring device, a micro-processing system and an alarm device. The sampling and detection device includes a new sampling nozzle, a detection system, a dryer, and a constant flow air pump, and the new sampling nozzle includes an adjusting piece, a sealing member, a fixing ring, and a connecting member. The speed measuring device includes an S-type pitot tube and a differential pressure transmitter. The new sampling nozzle described in the utility model does not need an external control system and can automatically adjust the caliber of the sampling nozzle with the change of the flue gas flow rate, thereby ensuring that the sampling system can use a A new type of sampling nozzle for isokinetic sampling.

Description

A Sampling System Capable of Realizing Constant Flow and Equal Speed Sampling

technical field

The utility model belongs to the technical field of environmental monitoring and belongs to the sampling technology. The sampling system can realize continuous isokinetic sampling in a large flue gas flow range and fluctuating flue gas flow.

Background technique

There are GB/T16157-1996, HJ/T 76-2007 and other relevant standards for the determination of particulate matter in the exhaust of fixed pollution sources and the sampling method of gaseous pollutants. The above standards all propose that the principle of constant velocity sampling should be followed when sampling particulate matter and gaseous pollutants in the exhaust of fixed pollution sources.

When sampling at constant flow rate and constant velocity, sampling nozzles with various calibers need to be prepared in order to satisfy the principle of constant velocity sampling under different flue gas flow rates. The diameter of the sampling nozzle corresponds to the flow rate of the flue gas. When sampling flue gas with different flow rates, the sampling nozzle needs to be replaced frequently.

At the same time, the flue gas flow rate may fluctuate locally during the period of continuous sampling at constant flow rate. Due to the fluctuation of flue gas flow rate, the sampling nozzle with fixed caliber does not meet the conditions of constant velocity sampling.

Contents of the invention

The purpose of the utility model of the present application is to overcome the deficiencies of the existing sampling technology, and to propose a novel sampling nozzle with ingenious and reasonable structural design. The sampling nozzle can automatically adjust the diameter of the sampling nozzle according to the change of the flue gas flow rate, so as to ensure that the sampling system can use a new type of sampling nozzle to perform constant-velocity sampling in a large range of flue gas flow velocity and when the flue gas flow velocity fluctuates.

The utility model is realized through the following technical solutions.

A sampling system capable of realizing constant flow and constant speed sampling, comprising a sampling detection device, a speed measuring device, a micro-processing system and an alarm device. The sampling and detection device includes a new sampling nozzle, a detection system, a dryer, and a constant flow air pump, and the new sampling nozzle includes an adjusting piece, a sealing member, a fixing ring, and a connecting member. The novel sampling nozzle, detection system, drier, and constant flow air pump are sequentially connected through pipelines. The constant flow air pump is used to draw air, and the flue gas is driven into the new sampling nozzle, detection system, and dryer in turn, and the detected gas is dried and then discharged. The inlet of the new sampling nozzle is formed by a plurality of adjusting pieces that can converge or spread evenly dispersed and fixed on the fixed ring, and the gap between two adjacent adjusting pieces is sealed with a seal. The seal is made of a material that has a small modulus of elasticity and does not affect the convergence or divergence of the flap. The fixing ring is used for fixing and supporting the adjusting piece. One end of the connecting piece is connected with the fixed ring, and the other end is connected with the air inlet of the detection system through the pipe fitting. The speed measuring device includes an S-type pitot tube and a differential pressure transmitter. The S-shaped pitot tube is fixed on the wall of the flue, and the velocity of the flue gas is measured at the center of the flue. The front and rear ends of the gas outlet of the S-type pitot tube are respectively connected to the high and low pressure ends of the gas inlet of the differential pressure transmitter through pipes. The pressure measured by the differential pressure transmitter is transmitted to the micro-processing system through the data line in the form of electrical signals. The micro-processing system is respectively connected with the differential pressure transmitter, the detection system and the alarm equipment through data lines. In the micro-processing system, the alarm threshold value can be set for the sampleable flue gas velocity range. The micro-processing system can control the detection system and alarm equipment through the data line.

The beneficial effect that the utility model has;

(1) In the traditional sampling process of flue gas, for different flue gas flow rates, it is necessary to frequently replace the sampling nozzle to achieve constant speed sampling; the new sampling nozzle described in the utility model can automatically adjust the diameter of the sampling nozzle according to the change of the flue gas flow rate , so as to ensure that constant velocity sampling can be achieved in a large range of flue gas flow rates;

(2) The sampling system described in the utility model can resist fluctuations in flue gas flow, realize constant-speed sampling, and reduce sampling errors;

(3) The sampling system described in the utility model has an alarm device, which can directly reflect the accuracy of the measurement process in the whole sampling process;

(4) Compared with the sampling technology at the present stage, the new sampling nozzle of the utility model does not need an external control system and can automatically adjust the diameter of the sampling nozzle according to the change of the flue gas flow rate to realize constant-speed sampling.

Description of drawings

Fig. 1 is a schematic diagram of the planar structure of the sampling system in the embodiment of the utility model;

Fig. 2 is a schematic diagram of the convergence of the regulating piece in the embodiment of the present invention.

In the figure, 1-new sampling nozzle, 2-S-type pitot tube, 3-differential pressure transmitter, 4-microprocessing system, 5-alarm equipment, 6-flue duct, 7-detection system, 8-dryer, 9-constant flow pump, 11-adjusting plate, 12-seal, 13-fixing ring, 14-connecting piece.

detailed description

In order to fully understand the technical content of the present invention, the technical solutions of the present invention will be further introduced and illustrated below in conjunction with specific examples, but the scope of protection is not limited to the above.

Example

As shown in Figure 1, a sampling system capable of constant flow and constant speed sampling described in the present invention includes a sampling detection device, a speed measuring device, a micro-processing system and an alarm device. The sampling and detection device includes a new sampling nozzle 1 , a detection system 7 , a dryer 8 , and a constant flow air pump 9 . The novel sampling nozzle 1, the detection system 7, the dryer 8, and the constant flow pump 9 are sequentially connected through pipelines. The constant flow air pump 9 pumps air, drives the flue gas to enter the new sampling nozzle 1, the detection system 7, and the dryer 8 in turn, and the detected gas is dried and then discharged. The detection system 7 uses a detector based on the principle of light scattering, which can detect particulate matter in the sampled gas. The dryer 8 can dry the detected gas. The inlet of the novel sampling nozzle 1 is formed by a plurality of regulating pieces 11 that can converge or diverge evenly and are evenly dispersed and fixed on the fixing ring 13 . As shown in Figure 2, there is an included angle θ ₀ between the cross section of the regulating piece 11 and the direction of flue gas flow. Part of the dynamic pressure energy of the flue gas will be converted into a static pressure F on the regulating plate 11 . Under the action of the static pressure F, the regulating piece 11 undergoes bending deformation as shown by the dotted line in Figure 2, so that the diameter of the sampling nozzle reaches a balance with the static pressure F received at a certain value. At this time, the diameter of the sampling nozzle and the flow rate of the flue gas satisfy the principle of constant velocity sampling. When the flue gas flow rate fluctuates, the fluctuation of the static pressure on the regulating piece 11 will cause elastic bending of the regulating piece 11 of the sampling nozzle. The flexural modulus of elasticity and the static pressure F quickly reach a balance, and at this time, the diameter of the sampling nozzle and the flow rate of the flue gas satisfy the principle of constant velocity sampling. The gap between two adjacent adjusting pieces 11 is sealed with a sealing member 12 . The sealing member 12 is made of a material with a small modulus of elasticity that does not affect the convergence or diffusion of the regulating piece 11 . The fixing ring 13 is used for fixing and supporting the adjusting piece 11 . One end of the connecting piece 14 is connected with the fixed ring 13 , and the other end is connected with the air inlet of the detection system 7 through the pipe. The speed measuring device includes an S-type pitot tube 2 and a differential pressure transmitter 3 . The S-shaped pitot tube 2 is fixed on the wall 6 of the flue, and the velocity of the flue gas is measured at the center of the flue. The front and rear ends of the gas outlet of the S-shaped pitot tube 2 communicate with the high and low pressure ends of the gas inlet of the differential pressure transmitter 3 through pipes respectively. The pressure measured by the differential pressure transmitter 3 is transmitted to the microprocessing system 4 through the data line in the form of electrical signals. The micro-processing system 4 is respectively connected with the differential pressure transmitter 3, the detection system 7, and the alarm device 5 through data lines. In the micro-processing system 4, an alarm threshold can be set for the sampleable smoke flow rate range. Microprocessing system 4 can control detection system 7 and alarm equipment 5 through data lines.

Claims (2)

1. the sampling system being capable of constant flow isokinetic sampling, it is characterised in that: include sampling detector for multifunctional, test the speed dress Put, microprocessing systems and warning device；

Described sampling detector for multifunctional includes novel sampling mouth, detecting system, exsiccator, constant flow air pump, its novel sampling mouth Including adjustment sheet, sealing member, retainer ring, connector；Described speed measuring device includes S type pitot tube and differential pressure transmitter；Described newly Type sampling mouth, detecting system, exsiccator, constant flow air pump are sequentially connected with by pipeline；Front and back end, S type pitot tube gas outlet is divided Tong Guo not be connected with differential pressure transmitter air inlet high-low pressure end by pipeline；Differential pressure transmitter institute measuring pressure passes through in signal of telecommunication mode Data wire is delivered in microprocessing systems.

A kind of sampling system being capable of constant flow isokinetic sampling the most according to claim 1, it is characterised in that: described Novel sampling mouth entrance by multi-disc can occur convergence or diffusion dispersed being fixed in retainer ring of adjustment sheet formed, adjacent Gap in the middle of two pieces of adjustment sheets uses sealing member to seal.