阅读说明：本技术 一种测定堆料表观密度的装置及其测定方法 (Device and method for measuring apparent density of piled materials ) 是由 杨丹 赵艳 胡昊 梁小冬 殷凤龙 于 2021-08-27 设计创作，主要内容包括：本发明公开了一种测定堆料表观密度的装置及其测定方法,有如下步骤,1)将测试罩扣于平整空旷的水泥地坪上,并标记好位置；2)打开调节阀,启动风机对测试罩保持充气；3)增大调节阀开度,对步骤2进行重复6次以上,读取P-(i)和流量计瞬时流量Q-(i)；4)关闭调节阀,测试罩内外压差将逐渐减小;5)移走测试罩,将已称重的质量为M的待测堆料倾倒在步骤1中的测试罩原来位置的轮廓内；6)按步骤1中测试罩标记点,将测试罩扣于原处；7)在测试罩内置待测堆料的状态下,重复步骤3和步骤4；8)计算出被测堆料的表观密度p。本发明结构合理,通过测定测试罩内部体积在内置和未内置待测堆料两种状态下的差值,实现堆料表观密度的准确测定。(The invention discloses a device and a method for measuring apparent density of stockpile, which comprises the following steps of 1) buckling a test cover on a flat and open cement terrace, and marking the position; 2) opening the regulating valve, and starting the fan to keep inflating the test cover; 3) increasing the opening of the regulating valve, repeating the step 2 for more than 6 times, and reading P i And instantaneous flow of flowmeter Q i (ii) a 4) Closing the regulating valve, and gradually reducing the pressure difference between the inside and the outside of the test cover, 5) removing the test cover, and pouring the weighed material pile to be tested with the mass M into the outline of the original position of the test cover in the step 1; 6) buckling the test cover in situ according to the test cover mark points in the step 1; 7) repeating the step 3 and the step 4 under the state that the test cover is internally provided with the stacking material to be tested; 8) calculating the apparent density of the measured piled material p . The structure of the inventionAnd reasonably, the apparent density of the stacking material can be accurately measured by measuring the difference value of the internal volume of the test cover in the two states of the built-in stacking material and the un-built-in stacking material to be measured.)

1. An apparatus for determining apparent density of a pile, comprising: open rigidity test cover (1) of end opening, its end opening cooperatees with smooth cement terrace (8), is installing differential pressure gauge (6) and thermometer (7) respectively on two through-holes that test cover (1) set up, and filter (3), governing valve (4) and flowmeter (5) that the exhaust pipe of fan connected gradually through it are connected gradually, and flowmeter (5) are connected with the fresh air inlet of test cover (1).

2. The method of claim 1, wherein the apparatus for determining apparent density of the bulk material comprises: there are the following steps of,

1) buckling the test cover (1) on a flat and open cement floor (8), and marking the position;

2) opening the regulating valve (4), starting the fan (2) to keep inflating the test cover (1), adjusting the opening of the regulating valve (4) to enable the differential pressure gauge (6) to be at a stable value, and further enabling the differential pressure gauge to be at a stable valueP ₁Recording, simultaneously recording, the first instantaneous flow of the flowmeter (5)Q ₁；

3) The opening degree of the regulating valve (4) is increased, the step 2 is repeated for more than 6 times, and a plurality of groups of differential pressure gauge (6) readings are obtainedP _i And the first instantaneous flow of the flowmeter (5)Q _i ；

4) The regulating valve (4) is closed, the pressure difference between the inside and the outside of the test cover (1) is gradually reduced, and the change rate d of the pressure difference value along with the time is recordedP _i /dt;

5) Removing the test cover (1), and pouring the weighed stack (9) to be tested with the mass M into the profile of the original position of the test cover (1) in the step (1);

6) buckling the test cover (1) in situ according to the mark points of the test cover (1) in the step 1;

7) repeating the steps 3 and 4 under the condition that the test cover (1) is internally provided with the stockpile (9) to be tested, and obtaining the reading of a plurality of groups of differential pressure gauges (6)p _i A second instantaneous flow rate of the flowmeter (5)q _i And the rate of change d of the internal and external differential pressure values with time after closing the regulating valve (4)P _i /dt, wherein maintenancep _i AndP _i the consistency is achieved as much as possible;

8) fitting P separately _i AndQ _i 、p _i andq _i the functional relationship between the internal and external differential pressure values of the test cover (1) and the instantaneous flow of the flowmeter (5) under two groups of test states is obtained and recorded as

Q _i =f(P _i ) Andq _i =g(p _i ) According to the formula

Calculating the apparent density of the measured piled materialp。

3. The apparatus of claim 1, wherein: the test hood (1) is made of metal or plastic or organic glass.

4. The apparatus of claim 1, wherein: the wind pressure of the fan (2) is 800-1300 Pa.

5. The method of claim 2, wherein the apparatus for measuring bulk apparent density comprises: the test cover (1) is not required to be effectively sealed with the cement terrace (8), and the consistency of two measurement states can be kept only by keeping the same placing positions before and after the test cover is placed into the to-be-measured stacking material (9).

6. The method of claim 2, wherein the apparatus for measuring bulk apparent density comprises: the difference value between the internal pressure and the external pressure of the test cover (1) is not higher than 1000 Pa.

7. The method of claim 2, wherein the apparatus for measuring bulk apparent density comprises: differential pressure values obtained in the absence of pile material in the test housing (1)P _i And obtaining the material to be tested in the built-in test cover (1)Pressure difference value ofp _i Are all set in the range of 500Pa to 1000 Pa.

Technical Field

The invention relates to the technical field of material density measurement, belongs to a determination method for determining apparent density of a stacking material, and particularly relates to a device and a method for determining the apparent density of the stacking material.

Background

Apparent density is the fundamental data of a material, referring to the ratio of the mass of the material to the apparent volume (real volume plus closed pore volume). The method can accurately measure the apparent density of the powder and granular bodies, and has important practical significance in the aspects of void ratio calculation, yield estimation, supply and demand measurement, process proportioning and the like.

Currently, a series of methods for measuring apparent density are established according to national standards for different types of continuous materials or powder particles, and typical methods include determination of foam and rubber apparent density (GB/T6343-2009/ISO 845: 2006), "determination of iron ore apparent density, true density and porosity (GB/T245886-2009)," determination of surfactant apparent density (GB/T6373-2007), "Industrial sodium tripolyphosphate test method" (GB/T9984-2008), "determination of wooden activated carbon test method/apparent density (GB/T12496.1-1999), and the like. These methods are all laboratory methods and are achieved by measuring the standard volume of a small sample of material and then weighing to obtain the apparent density. In order to make the measured result as close as possible to the true value of the apparent density, the method not only has requirements on the particle size specification of the material, but also makes the measured result of the volume of the material close to the apparent volume by using drainage (for large-particle materials such as iron ore), compaction (for powder materials such as various industrial powders) and other means during measurement. However, drainage or compaction may alter or break the material properties, leading to large errors in the measurement results. Furthermore, the existing measurement methods do not truly reflect the apparent density of the material, particularly the bulk material, subject to the sampling volume of the material. Further, in the case of an uneven powder pile, the structure of the voids between the particles is complicated, and the limitation of measuring the apparent density by the above method is large.

Disclosure of Invention

The invention aims to provide a device for measuring the apparent density of a piled material, which has a reasonable structure, is convenient and quick to operate and can accurately measure the apparent density of the piled material of the powder particles on site.

Another object of the present invention is to provide a method for determining apparent density of a pile, which can determine the difference between the internal volume of a test enclosure in a built-in state and a non-built-in state of the pile to be measured, thereby realizing accurate determination of the apparent density of the pile.

The purpose of the invention is realized as follows: the utility model provides a survey device of windrow apparent density, the open rigidity test cover of end opening, its end opening cooperatees with smooth cement terrace, is installing differential pressure gauge and thermometer respectively on two through-holes that the test cover set up, and the exhaust pipe of fan is through the filter, governing valve and the flowmeter that connect gradually on it, and the flowmeter is connected with the fresh air inlet of test cover.

The test hood is made of metal or plastic or organic glass.

The wind pressure of the fan is 800-1300 Pa.

The air volume can be but is not limited to 1700-3500m³/h。

The test cover does not need to be effectively sealed with the cement terrace, and the consistency of two measurement states can be kept only by keeping the same placing positions before and after the test cover is placed into the to-be-measured stacking material.

The difference value between the internal pressure and the external pressure of the test cover is not higher than 1000 Pa.

Differential pressure values obtained in the absence of pile material in the test housingP _i And the pressure difference value obtained under the state that the test cover is internally provided with the stacking material to be testedp _i Are all set in the range of 500Pa to 1000 Pa.

The purpose of the invention is realized as follows: a method for measuring apparent density of piled materials comprises the following steps,

1) buckling the test cover on a flat and open cement terrace, and marking the position;

2) opening the regulating valve, starting the fan to keep inflating the test cover, and regulating the opening of the regulating valve to make the differential pressure gauge in a stable value so as toP ₁Recording and simultaneously recording the first instantaneous flow of the flowmeterQ ₁；

3) Increasing the opening of the regulating valve, repeating the step 2 for more than 6 times to obtain a plurality of groups of differential pressure gauge readingsP _i And the first instantaneous flow of the flowmeterQ _i ；

4) Closing the regulating valve, gradually reducing the pressure difference inside and outside the test cover, and recording the time-dependent change rate d of the pressure difference valueP _i /dt;

5) Removing the test cover, and pouring the weighed stockpile to be tested with the mass M into the outline of the original position of the test cover in the step 1;

6) buckling the test cover in situ according to the test cover mark points in the step 1;

7) repeating the step 3 and the step 4 under the state that the test cover is internally provided with the stacking material to be tested, and obtaining a plurality of groups of differential pressure gauge readingsp _i Second instantaneous flow of the flowmeterq _i And the rate of change d of the internal and external differential pressure values with time after closing the regulating valveP _i /dt, wherein maintenancep _i AndP _i the consistency is achieved as much as possible;

8) fitting P separately _i AndQ _i 、p _i andq _i the functional relationship between the internal and external differential pressure values of the test cover and the instantaneous flow of the flowmeter under two groups of test states is obtained and recorded as

Q _i =f(P _i ) Andq _i =g(p _i ) According to the formula

Calculating the apparent density of the measured piled materialp。

The invention comprises a test cover, a fan, a filter, an adjusting valve, a flowmeter, a differential pressure gauge and a thermometer. The test cover is installed on the test terrace, and the differential pressure gauge and the thermometer are connected on the test cover. The fan exit linkage filter, the governing valve is connected to the filter, and the flowmeter is connected to the governing valve, and the flowmeter passes through the tube coupling test cover.

The test cover is a rigid structure with an open bottom, and the material of the test cover can be a light cover body made of metal, plastic, organic glass and other materials. The fan is a common fan with low pressure head and large air volume. The filter is used for filtering dust, water vapor, oil mist and the like. The regulating valve is a butterfly valve capable of manually or automatically regulating the opening.

Has the advantages that:

(1) when the gas is filled, the gas only fills the gaps between the materials and the pores communicated with the outside, so the measured result accurately reflects the apparent density of the materials. (2) The difference value between the internal pressure and the external pressure of the test cover is not higher than 1000Pa, and the requirements on the pressure head of the fan and the strength of the test cover are not high. (3) The test hood need not be effectively sealed with the floor. The consistency of the two measurement states can be kept as long as the placing positions of the tested piled materials before and after the piled materials are placed are kept the same, so that the scheme has the advantages of rapidness, convenience and simplicity.

The invention has reasonable structure, has low requirement on the strength of the pressure head and the test cover of the fan, accurately reflects the apparent density of materials and improves the working efficiency.

Drawings

The invention will be further described with reference to the accompanying drawings, and fig. 1 is a schematic diagram of the structural principle of the invention.

Detailed Description

A device for measuring apparent density of stockpile is shown in figure 1, a rigid test cover 1 with an open lower opening is provided, the lower opening of the rigid test cover 1 is matched with a flat cement terrace 8, a differential pressure gauge 6 and a thermometer 7 are respectively arranged on two through holes arranged on the test cover 1, an exhaust pipe of a fan is sequentially connected with a filter 3, a regulating valve 4 and a flowmeter 5 through the exhaust pipe, and the flowmeter 5 is connected with an air inlet hole of the test cover 1.

A measuring method of a device for measuring apparent density of a pile is disclosed, as shown in figure 1, and comprises the following steps:

1. selecting a flat and open cement terrace, buckling the test cover 1 on the terrace and marking the position;

2. opening the regulating valve 4, starting the fan 2, keeping the test cover 1 inflated, and adjusting the opening of the regulating valve 4 until the differential pressure gauge 6 is at a stable value, so as toP ₁Recording, simultaneously recording the first instantaneous flow of the flowmeter 5Q ₁Recording;

3. increasing the opening of the regulating valve 4, repeating the step 2 for more than 6 times, and obtaining a plurality of groups of readings of the differential pressure gauge 6P _iAnd the first instantaneous flow of the flowmeter 5Q _iIn the practical use process,P _imay be, but is not limited to, 500Pa to 1000 Pa;

4. the regulating valve 4 is closed, the pressure difference between the inside and the outside of the test cover 1 is gradually reduced, and the change rate of the pressure difference value along with the time is recordeddP _i / dt；

5. Remove the test hood 1 and weigh a mass ofMThe stockpile to be tested is poured into the outline of the original position of the test cover 1 in the step 1;

6. buckling the test cover 1 in situ according to the mark points of the test cover 1 in the step 1;

7. repeating the steps 3 and 4 under the condition that the test cover 1 is internally provided with the stockpile to be tested, and obtaining the readings of a plurality of groups of differential pressure gauges 6p _iSecond instantaneous flow of the flowmeterq _iAnd the rate of change of the internal and external differential pressure values over time after closing the regulating valvedp _i /dtIn which holdp _iAndP _ithe consistency is as much as possible, and in practical use,p _imay be, but is not limited to, 500Pa to 1000 Pa;

8. fitting separatelyP _iAndQ _i、p _iandq _ithe functional relationship between the internal and external differential pressure values of the test cover and the instantaneous flow of the flowmeter under two test states is obtained and recorded asQ _i=f(P _i) Andq _i=g(p _i) In practical use, the fitting function may be in the form of, but not limited to, a polynomial, a power function, etc.,

calculating the apparent density of the measured pile according to the following formulaρ

。