洪堡溶液比重计分析

什么是比重计?

比重计用来测量液体的相对密度. They are primarily made of glass and have two parts: the hydrometer with a mercury weighted bulb at the bottom and a cylinder with graduation marks. The science behind the hydrometer is simple – the lower the density of the liquid, 比重计下沉得越多.

为什么比重计用于土壤粒度分析?

Sieve analysis is used for soil analysis; however, it becomes inaccurate with grain sizes around 0.075 mm. 200筛). The risk of losing samples becomes high and it is not practical to design sieves any smaller. Hydrometer soil analysis is used in conjunction with standard sieve analysis of fine-grained soils to provide a complete gradation curve or gradation profile.

比重计分析理论

比重计土壤分析基于斯托克斯定律, which claims that the velocity at which a particle settles while suspended, 其他因素都一样, 是由形状决定的吗, 颗粒的重量和大小. Because it is assumed that soil particles have the same specific gravity, it’s expected that larger particles will settle more quickly than finer ones in a soil-water suspension. Hydrometers are able to measure a soil’s particle-size distribution by measuring suspended solids in sedimentation cylinders.

样品制备

Dry sieving is used first to remove larger particles before the distribution of particles smaller than 0.075mm可以用比重计测定.

潮湿的准备

This is the preferred method as it maintains soil moisture properties during the preparation process. 在这里，样本通过一个2.0毫米(不. 10)用橡皮刮刀筛. 保持样品内的水分，或根据需要增加水分.

脱水制备

This method is only allowable if the sample arrives in “air-dry condition”. Clumps of soil may be broken up using a mortar with a rubber-tipped pestle. 然后土壤通过一个2.0毫米(不. 10)筛.

计算沉降试样所需的质量

用筛子筛过样品后, it is time to calculate the mass of your sample that will be required for hydrometer testing. 这个计算是基于样品的水分含量, the sediment capacity of your hydrometer and the estimated percentage of your sample that passes through the 0.075毫米(不. 200)筛.

地点:

M_最高明的  =估计湿质量，最接近1g;

H_c        =比重计容量，g

%est =物料通过测试的估计百分比.075毫米(不. 200)筛到最接近的1%

W_c   =估计含水量至最接近的1%

In most instances you should expect to calculate between 50 – 60 g of material finer than the 2.00 mm(否. 10)用于比重计试验的筛子.

悬浮土壤样本

六偏磷酸钠 是否有分散剂能防止样品结块. This dispersion agent should be added to distilled water to create a dispersion solution. 所需分散剂的数量取决于土壤类型. Once you have prepared your dispersion solution, place your sample into a 250ml的玻璃烧杯 然后加入分散溶液. 将样品浆冲洗成 带有搅拌装置的分散杯 搅拌一分钟. 搅拌后, 加入1000ml沉淀池中，小心加水, 将气缸充至1,000毫升马克. You may mix the solution with the water by manually inverting (the “tipping method”), 不过，最好使用土壤搅拌器. Cover your cylinder and leave it overnight so that the solution will equilibrate. 这既可以在室温下进行，也可以在 恒温水浴.

 比重计试验规程

1. 开始测试, the suspension must be mixed again (using either the tipping method or the agitator). 使用计时器来记录混合溶液所需的时间.
2. 混合完成后, place the cylinder on the work bench (if testing in an environment where room temperature will be maintained) or into the constant temperature bath. If foam has formed during mixing that will interfere with hydrometer readings, 可加入3-5滴异丙醇以减少泡沫.
3. 使用计时器, 记录1分钟时的读数, 2分钟, 4分钟, 15分钟, 30分钟, 60分钟, 240分钟和1440分钟.
   • 取这些读数, the hydrometer must be lowered into the suspension 20 seconds prior to the reading. Maneuver the hydrometer to the level where the reading will take place and allow for hydrometer stabilization.
   • The reading should take place at the top of the meniscus and rounded to the nearest 1/4 graduation.
   • Hydrometer extraction should be done in one fluid motion over 5 to 10 secs. 灯泡末端应该有一滴液体吗, carefully touch the hydrometer end to the sedimentation cylinder so that the drip can rejoin the suspension.
   • The hydrometer should then be placed into a cylinder of clean water and gently spun to clean.
   • Be sure to remove and dry the hydrometer before taking additional readings.
4. Following each hydrometer measurement, temperature of the solution should me measured. It is important to use a thermometer that has been standardized and has an accuracy and readability of at least ±0.当浸入深度为25至80毫米时，温度为5°C.
   • To record the temperature, gently insert the thermometer without disturbing the suspension.
   • Temperature readings are valid for 30分钟 and do not need to be repeated within that time.
5. After all measurements have been taken, the suspension is transferred to an oven drying container.
6. When drying is complete, weigh the remaining solids to determine the total dry mass. 然后将样品浸泡在水中，并在0.075毫米(不. 200)筛.
7. 称量并记录所留物料的重量.075毫米筛.

为什么需要洪堡比重计测试?

恒定的温度对准确的测试结果很重要. The hydrometer constant temperature bath developed by 洪堡 provides both heating and cooling to guarantee your samples stay at the desired temperature, 不管你在什么环境下工作.

该程序所需的材料包括土壤比重计, 比重计瓶浴, 恒温水浴, 土壤分散混合器和六偏磷酸钠. All these 项目 are available from 洪堡, either as sets or individual 项目 to meet your needs.

我们提供:

比重计分析套装 – Complete kit with all you need to determine the distribution of soil particles smaller than 75μm

比重计瓶浴 – Unit is designed to hold eight 液体比重计Jars in a constant-temperature bath, 其中包括加热和冷却

摘要土壤 – Measure the distribution of soil particle sizes by analyzing suspended solids in sedimentation cylinders

液体比重计Jar -用于悬浮固体以供评价的分级圆柱体

土壤分散混合器 – Method for dispersing soil suspensions for hydrometer analysis using high-speed mixing

空气喷射分散管 – Provides a method to disperse soil suspensions directly in the Hydrometer Jar

分散式手动搅拌器 – A handheld way to break up soil suspensions directly in the Hydrometer Jar

洪堡的专家可以回答您的任何问题. 请参阅我们的 支持页面 或打电话 1.800.544.7220 与代表交谈.