LBN-Ⅱ落棒粘度计

使用说明书

上海现代环境工程技术股份有限公司

             地址：上海市青浦区徐泾镇徐旺路18号

             电话：021-59884839  021-64397454

             邮编：201702

            网址:http://www.moderner.com

一、概述：

落棒粘度计（也称拉雷粘度计）是用于测定印刷油墨等非牛顿流体（粘度随剪切速率变化的流体）某些流变特性（表观粘度、假屈服值、短度等）的常用仪器。通常认为拉雷落棒试验结果能较理想的描述油墨在印刷过程中的部分流变特性，适用于油墨生产期间粘度的实际控制，并经常作为卖买双方验收的技术要求。LBN-II型落棒粘度计是参照国际标准ISO12644：1996（E）《印刷技术—使用落棒粘度计测定浆状油墨及其连接料的流变特性》设计制造的，其原理是：测量不同加载荷重落棒通过涂有测试样品的孔隙所需下落时间，借助适当的流动模型（卡逊模型，宾汉姆模型或指数定律模型），通过应用线性回归方法以获得样品的表观粘度（某一剪切速率下的粘度值，拉雷落棒试验获得的表观粘度有时也称为拉雷粘度）、屈服值和短度比（常简称为短度）。

二、主要技术参数：

1、使用电源：                           220V 50Hz

2、适用表观粘度范围：                      2~200Pa·s

3、落棒尺寸：                          F12×300mm

4、落棒重量：                           132g

5、砝码组克数（共4075g）：     25-50-100-200-200-500-1000-1000-1000g

6、仪器外形尺寸（长×宽×高）：      140×140×300mm

7、重量（含仪器、砝码盒、控制箱）：    18kg

三、操作准备：

1、将仪器从盒内取出置于工作台上，调整仪器水平。

2、插好信号连接线插头，将温度传感器插入落棒导套的斜孔内。

3、将恒温水槽（需另行购置）引出的两根乳胶管分别与恒温水套相连接。

4、接通电源，打开恒温水槽和仪器控制箱的电源开关，显示屏显示温度为当前导套的摄氏温度，时间显示为0.00秒。（注：恒温水槽的具体操作方法见恒温水槽说明书。）

5、整个测定期间实验室温度应保持为25℃±2℃。当导套温度达到标准规定的25℃±0.2℃时，就可以开始进行测定。

6、操作时为尽量降低人体温度造成的升温，应避免裸手接触粘度计的落棒、导套。在需接触落棒、导套时要戴手套或在手里垫一小块棉布。

四、操作概要：

1、测定前，每次取约5g的受测样品，用小调墨刀在玻璃板上加以调匀，检查没有任何粗颗粒和杂物。受测样品的量应能足够覆盖落棒导套环状凹槽。

2、将落棒垂直插入落棒导套孔内并轻轻降落至旋转挡板上。用塑料调墨刀将经调匀的受测样品涂布在落棒和导套环状孔的槽内；轻轻旋转落棒，使受测样品均匀分布在凹槽周围；同时可用指尖从落棒底部将落棒轻轻抬起约20毫米，使受测样品尽可能靠近槽底，松开手指让落棒下落到旋转挡板上，以确保凹槽充满受测样品。

3、任选一荷重砝码置于落棒顶部，移开旋转挡板以使落棒下落，让受测样品润湿落棒和导套；同时请确认光电开关和温度传感器工作正常（下落时温度固定显示为下落开始时的温度，时间显示为下落计秒；下落结束时温度显示为下落结束时的温度，时间显示为实际的下落秒数；拉起落棒后温度恢复显示为导套实测温度，时间自动清零）。

4、避免任何可能刮伤落棒的操作，不准使用金属刮墨刀对落棒进行操作；不准在无受测样品情况下作下落操作。下落完毕，将落棒轻轻拉起并搁置在旋转挡板上。用塑料调墨刀将落棒上的油墨刮下，将其涂在落棒的下部以及导套环状凹槽内。

5、选择适当的荷重砝码组合：按上述3~4步骤选择砝码做下落试验，以确认所选最大荷重砝码的下落时间在4～10秒范围内（美国标准ASTM D4040-05推荐为尽量接近1~2秒），其余砝码的下落时间不超过60秒。通常选取4~5个不同重量的荷重砝码组合。

ISO标准推荐如下的荷重砝码组合：（单位：g）

A：  5000   4000   3000   2000   1000

B：  3000   2000   1500    500

C：  1500   1000    800    500

D：   800    600    400    200

E：   400    300    200    100

F：   200    100     50      0

6、受测样品的测定从砝码组合中最重的砝码开始，此最重砝码至少要做到两次下落时间差不超过0.5秒，才可以依次更换轻一点的砝码进行测定。开始测定前按上述1~2步骤准备受测样品；每完成一次下落，必须用塑料调墨刀将落棒上的油墨刮下，将其涂在落棒的下部；测定中不得添加受测样品；如果测定过程中发现受测样品不够用了，清洗落棒和导套，然后取新的受测样品重复上述1~2步骤。每种重量的砝码各测定3次，每次均记录落棒下落时间（精确到0.01秒）和测定时导套的温度（精确到0.1℃）。

7、测定操作应迅速且不能中断，全部操作应在5到10分钟内完成。很多印刷油墨和连结料都含有强挥发性的溶剂，除非严格控制实际暴露时间，否则操作时的挥发损失可能使测定结果发生较大偏离。如果发现连续数次落下同一荷重砝码的落棒，下落时间会变长，就说明有明显的挥发性损失存在（此时宜选取较重的砝码组合以减少测定时间）。

8、粘度测定对温度有很强的敏感性，所以温度必须在测定过程中得到控制和监测。原则上操作前如果导套温度超过25.2℃，温控设备必须重新设定；如果在整个测定过程中导套温度变化超出25℃±1℃，试验必须重做。

9、测定完成后及时做好仪器的清洁保养工作，特别是落棒和导套的清洁工作一定要及时、仔细、彻底。清洗应使用不起绒毛的布或纸和适当的溶剂。

五、数据处理概要：

1、参照ISO标准，定义仪器常数a、b如下：

  ……………………………（1）

 ……………………………（2）

式中：L——落棒下落的距离（m）

          s——落棒和导套缝隙间样品膜厚（m）

          g——重力加速度（取9.80665m/s²）

         p  ——圆周率（取3.14159）

         r——落棒半径（m）

       l——导套等效圆柱状部分长度（m）

2、剪切速率和剪切应力可按下式求得：

 ………………………………（3）

 ……………………………（4）

式中：g ——剪切速率（s^-1）

      t——落棒下落时间（s）

     s——剪切应力（Pa）

      m——落棒和荷重砝码的总质量（kg）

3、粘度可按下式求得：

 ………………………………（5）

式中：h——粘度（Pa·s）

4、对牛顿流体来说，粘度h是一不变的常量，简单取各次测定结果计算后的平均值即可获得受测样品的粘度值。但落棒粘度计主要是用来测定非牛顿流体粘度的，此时粘度h是随剪切速率g不同而变化的，各次测定结果计算后获得的粘度值是不同的。为区分于牛顿流体的粘度值，通常将非牛顿流体的这些不同粘度值称为表观粘度。为使测定的表观粘度值具有可比性，必须规定统一的剪切速率值。ISO标准规定取2500s^-1剪切速率（通常认为该剪切速率适用于描述印刷油墨的流变特性）下的表观粘度值作为受测样品的表观粘度（有时也称为拉雷粘度）。

5、为了由各组测定数据导出2500s^-1剪切速率下的表观粘度，就必须对剪切应力和剪切速率间的函数关系作某些假设，通常称为流动模型。ISO标准推荐了三种流动模型：卡逊模型、宾汉姆模型和指数定律模型，同时指出该三种模型均适用于描述某些印刷油墨的流变特性，应由用户按实际情况予以选择。并指出该三种模型间不存在某种转换公式。

6、虽然ISO标准推荐了三种流动模型，但落棒粘度计通常是采用指数定律模型来做数据处理的（在ASTM D4040-05《使用落棒粘度计对浆状油墨及其连接料流变特性的标准测试方法》中只推荐了指数定律模型的处理方法）。因此本说明书的测定数据处理部分仅涉及该方法（其余流动模型的处理请用户自行参阅ISO标准）。其实ASTM标准对操作过程的描述远比ISO标准详尽，也可作为使用参考（但ASTM标准对仪器参数的规定和计算与ISO标准有出入，阅读时请注意）。

7、ISO标准定义的指数定律模型如下：

 ………………………………（6）

式中：k——与流体粘度有关的常数

          N——表征流体的非牛顿特性程度的常数

8、对牛顿流体，N=1；N<1的非牛顿流体是剪切变薄的流体（假塑性流体），大多数印刷油墨是剪切变薄的；N>1的非牛顿流体是剪切变厚的流体（胀流型流体），对印刷油墨及其连接料来说，通常是不存在这种情形的。如果测定结果出现N大于1~1.05的情形，请核对测定数据或重做测定。

六、测定数据处理：

1、如果测定过程中温度超出25℃±0.2℃范围，则下落时间应按下式进行修正：

              t＝t_测[1＋d_t(T_测－25)]

式中：t ——修正后的下落时间（s）

          t_测——测定时记录的下落时间（s，对同一砝码下落取平均值）

d_t——温度修正系数，对印刷油墨来讲，推荐采用0.1

T_测——测定时记录的温度（℃，对同一砝码下落取平均值）

2、下落质量m是落棒和荷重砝码的总质量（kg）。将各组t，m值代入公式（3）和（4）获得每组的s和g值（仪器常数a和b随仪器已给出）。

3、对指数定律模型方程二边取对数，得到如下的线性关系式：

logs= log k+N logg

     利用步骤2中求得的各组s，g值对上式做线性回归可求得log k和N，进而求得k和N。

4、线性回归的相关系数作为测定数据有效性的判定依据：相关系数大于等于0.999则认为结果有效；相关系数较低则测定必须重做。

5、测定结果按如下公式计算获得：

     表观粘度（拉雷粘度）=k·2500^N-1

     假屈服应力（屈服值）= k·2.5^N

     短度比（或称短度）=假屈服应力/表观粘度

6、仪器在出厂前和使用一定时间后必须进行校准。如果仪器的测定粘度与标准油粘度数据相差超过20%，该组落棒和导套组合必须被更换；如果相差不超过20%，可采用粘度修正系数d来进行补偿。表观粘度按下式计算：

     表观粘度=d·k·2500^N-1

7、以上是测定数据处理的简要说明，实际计算是采用计算机软件来完成的（软件由随机附赠的光盘提供）。

七、使用注意事项：

1、落棒、导套和光电开关、控制箱必须按编号配对使用，不可仪器间交叉混合使用，否则随仪器给出的仪器常数a、b无效。

2、落棒和导套属于精密零件，其精度直接影响测定数据。因此受测样品中绝不可含有高硬度杂质；用于刮油墨的调墨刀也必须使用塑料或其他软质材料，以免刮伤落棒。

3、仪器常数a、b和粘度修正系数d在出厂前由本公司检测人员测定并随附赠的光盘给出。

4、在使用过程中，落棒和落棒导套不可避免会产生磨损，仪器常数和粘度修正系数也会随之有所变化，因此仪器通常应每年鉴定、校正一次。

5、落棒粘度计是用于化工原料测试过程的，用户在使用前应当按相关安全规定建立适当的安全和卫生防护措施并确定规章制度。与化工原料接触有关的安全问题应当由用户予以确立，不属本说明书的叙述范围。

6、本公司将根据市场和客户的需求不断地改进和开发产品，本说明书如有变动，恕不另行通知。

Laray Viscometer

INSTRUCTION MANUAL

Shanghai Modern Environment Engineering Technique Co., Ltd

Address: No.18 XuWang Road XuJing Town, QingPu District, Shanghai, China

Tel: 86-021-64397454    Fax: 86-021-59884835

Internet:http://www.moderner.com

E-mail:Marketing@moderner.com

Laray Viscometer

Ⅰ. Introduction:

LarayViscometeris an instrument applicable to determine the rheological properties ( apparent viscosity、pseudo yield value、shortness, etc ) of Non-Newtonian liquids (viscosity increases with shear rate). LaryaViscometerdesigned and produced by our company is in accordance with the specification of ISO12644: 1996(E)Graphic technology—Determination of rheological properties of paste inks and vehicles by the Falling RodViscometer. Its principle: measuring fall times by loading the rod with different load weights pass the gap which is filled with the test fluid. By applying linear regression methods & by means of suitable flow model ( Casson model, Bingham model or Power Law model ) to obtain apparent viscosity、yield value、shortness ratio of sample.

Ⅱ. Main Technical Parameters:

1. Input voltage: 220V 50Hz

2. Range of apparent viscosity: 2-200Pa·s

3. Dimensions of the falling rod: Φ12×300mm

4. Weight of the falling rod: 132g

5. Sets of load weights ( total 4075g ): 25-50-100-200-200-500-1000-1000-1000g

6. Overall dimensions: 140mm×140mm×300mm(length by width by height)

7. Weight( including instrument、weight box、controller ): 18kg

III. Preparation before operation:

1. 1.   Take the instrument out from the box, level it.
2. 2.   Insert signal connecting wire plug, insert temperature sensor into diagonal hole of guide bush of Laray Viscometer.
3. 3.   Separately connect two lead out latex pipes from thermostatic bath (ordering separately) to thermostatic (water) jacket.

4. Turn on power, switch on the power of thermostatic bath and electronic controlling box, temperature indicator display current temperature of guide bush of falling rod Viscometer, timing indicator should display 0.00 sec. (Note: specific operation of thermostatic bath refers to instruction manual).

5.Testing Environment: 25℃±2℃. When the temperature of guide bush of Falling Rod Viscometer reaches 25℃±2℃, the test shall be carried out.

6. During operation, a naked Hand should be avoided to touch guide bush & falling rod so as to cause man-made warming-up. Guide bush & falling rod should be touched by hand with glove.

IV. Test procedure:

1. 1.   Prior to use, the test sample (about 5g) shall be kneaded by a spatula and equilibrated to test temperature. The sample shall be homogeneous and not contain any coarse particles. An amount of the test sample sufficient to coat the rod and aperture is applied to the lower part of the rod.
2. 2.   The bottom of the rod is inserted into the aperture of guide bush and slightly fall on the turntable, the sample is distributed uniformly around the gap, the gap is filled with the test fluid which is sheared when the rod falls by using fingertip; lift the bottom of the rod 20mm, then fall on the turntable.
3. 3.   Load weights to be loaded on top of the rod, remove a turntable to let falling rod fall, the rod and the aperture are wetted by the liquid; Make sure that photoswitch & temperature sensor are working normally (temperature indicator display starting temperature when starting falling, time indicator starts to display seconds; temperature indicator display finishing temperature when finishing falling, time indicator display actual fall time; temperature resume to display actual temperature of guide bush after pulling up the rod, time automatically clear.
4. 4.   Avoid any scoring operation forthe rod, the metal spatula should not be allowed operation forthe rod; Don’t do falling operation under the condition of no test sample. After finishing falling, the rod is lightly pulled up and rested on the support. After each run, the rod is scraped withthe spatula and the liquid which wasscraped off is reapplied on the lower part of the rod & the aperture of guide bush.
5. 5.   The proper sets of load weights is selected according to the expected results. The fall time with the heaviest load weight should normally be in the range from 4s to 10s ( ASTM D4040-05 recommend 1-2s. Series of load weights are combined to sets. Sets of load weights with the following masses should be used: (Unit: g)

A: 5000   4000   3000   2000   1000

B: 3000   2000   1500    500

C: 1500   1000    800    500

D: 800     600    400    200

E: 400     300    200    100

   F: 200     100     50      0

1. 6.   The sample is tested with the heaviest load weight at the beginning of the tests, load weighs in descending order. Fall time during the test with the heaviest load weight varies less than 0.5s, the sample is tested with the selected series of load weights in descending order. The fall time shall not exceed 60s. After each run, the rod is scraped with the spatula and the liquid which was scraped off is reapplied on the lower part of the rod. During the test, additional liquid shall not be added. The sample is tested with each load weight for three times. By loading the rod with different load weights record the fall time every time ( correct to 0.01s), and temperature of guide bush during measurement ( correct to 0.1℃).
2. 7.   Operationshall be done quickly and can’t be interrupted, the whole operationshall be finished within 5-10 minutes. Many printing ink and vehicles have strong volatile solvent, only if strictly control actual exposition time, otherwise volatile loss cause large deviation of test result during operation. If found several continuous falling with the sameload weight, fall timecould be longer, it indicates that obvious volatile loss exists.
3. 8.   Viscosity is strongly temperature dependent, therefore the temperature shall be controlled and monitored. Principally, if the test temperature varies from reference temperature (25℃) by more than 0.2℃ before the runs, the thermostatic equipment shall be reset. if the temperature during the test varies more than 1℃, the test shall be repeated.
4. 9.   Afterthetest, the instrument shall be cleaned immediately with a lint-free wiper and a suitable solvent, especially the rod & guide bush.

V. Data process

1. For the purpose of ISO standard, device factor α、βis defined as the following ratio,

    ……………………………（1）

 ……………………………（2）

  Where: L-is the measuring distance (m)

         s-is the thickness of the ink in the nip determined by the difference between radii of the aperture and of the rod (m).

         g-is the gravitational acceleration (9.80665m/s²)

        π-is the circumference ratio（3.1416）

r-is the radius of the rod (m)

l-is the length of the aperture (m)

2. Shear stress & shear rate

 ………………………………（3）

 ……………………………（4）

 Where:γ-is the shear rate (s^-1)

        t-is the fall time (s)

        σ-is the shear stress (Pa)

        m-is the total mass of the rod and the weight load (kg)

3. Calculate viscosity

   ………………………………（5）

      Where:η-viscosity (Pa·s)

1. 4.   For Newtonian liquid, viscosityhis constant, calculating average value as viscosity of tested sample. But Falling Rod Viscometer is used for testing viscosity of Non-Newtonian liquid of tested sample; the viscosity is changed according to different shear rate. Apparent viscosity (also called Laray viscosity) is for Non-Newtonian liquid of tested sample, ratio of the shear stressσto the shear rateg, at adefined shear rate when applying describe rheological behaviour of printing ink, typically to 2500s^-1.
2. 5.   Apparent viscosityat 2500s^-1, ratio of the shear stresssto the shear rateg   ISOrecommends three flow models: Casson model、Bingham model and Power Law model, these three models mentioned are suitable for describing therheological behaviour of inks. The selection of a specificmodelshould be determined by practical experience. The values of each of the rheological quantities strongly depend on the selection of theflow model. There are no equations to transform the results from one model to any other.
3. 6.   Although ISO standard??recommends three flow models,Laray Viscometer generally adoptsPower Law model for calculation (ASTM D4040-05Determination ofrheological properties of paste inks and vehicles by the Falling Rod Viscometer)only recommends Power Law model for calculation.Otherflow model’s calculation refers to ISOstandard.
4. 7.   ISO standard defines Power Law model:

??                σ=kγ^N??………………………………（6）

Where: k-constants relates to fluidviscosity.

       N—describesconstants ofnon-Newtonian characteristic gradation.

1. 8.   For Newtonian fluid,N=1; N<1’snon-Newtonianshear thinning liquids (pseudoplastic fluid), most printing ink shear thinning liquids; N>1’snon-Newtonianshear thickening liquids (dilatant fluid),。For printing ink and vehicles, usually it doesn’t exist suchsituation. IfN>1-1.05, please check data or the test shall be repeated.

VI. Data Process:

1.If the test temperature varies from reference temperature (25℃±2℃) during testing, the following equation is used to correct the fall time:

                  t=t_measured[1+δ_t(T_measured-25)]

   Where: t- fall time after correcting (s)

          t_measured- fall time during test. (s, is defined to be average for same weight)

      δ_t-temperaturecorrection factor, for printing ink, it recommends adopting 0.1

T_measured-temperatureduring test (℃, is defined to be average for same weight)

2.Fall mass (kg)is the total weight of the rod and the weight loads. Equation (3) and (4) are used together with t and m-per group (the device factorα&βhave been given) to calculateσandγ.

3.For Power Law model, a double logarithmic plot of shear stress versus shear rate is used to obtain the following linear relation.

                      Logσ=logk+N logγ

Using step 2 calculateσandγeach group, values of logk and lon N are obtained from linear regression using above equation, then calculate k and N.

4.Linear regression correlation coefficient should be calculated asa measure of the repetability of the test. For correlation coefficient values of 0.999or better the results are reliable. In case of lower correlations the test shall be repeated.

5.Test results are obtained with the following equation

Apparent viscosity (Laray viscosity) = K·2.5^N-1

Pseudo yield stress (yield stress)=K·2.5^N

  Shortness ratio(Shortness) =Ratio of pseudo yield stress to the apparent viscosity.

6.If a certain set of rod and aperture ring shows viscosity variations of >20% from the specifications of the standard viscosity oil it shall be discarded. Smaller differences are compensated by using a correction factorδ. The following equation is used to calculate apparent viscosity:

                    Apparent viscosity=δ·k·2500^N-1

7.The above shows brief introduction about data Process, actual calculation adopts software (software is provided by an attached disc).

VII. Note:

1. 1.   The rod、guide bush andphotoswitch、controlling box must be matching operation according to number, they should not be interlace operation, otherwise device factorsa、bwill be invalid.
2. 2.   The rod and guide bush are high accuracy parts, their accuracy directly influence data, so tested sample is not allowed to contain any coarse particles, the spatula used for scrapping ink must be made of plastic or other soft material so as to avoid scoring.
3. 3.   Device factorsa、band acorrection factorδare measured by our company’s examiner in our factory, attached with a disc.
4. 4.   During measurement, a rod and a guide bush wear continuely, device factors andcorrection factor also vary a little bit,so the viscometershould be sent back to our company for checking & correcting every year.
5. 5.   Laray Viscometer is used for chemical material process, safety and health protective step must be set up in accordance with all local codes and ordinances. Before using this machine, safety problem associated with chemical material must be established by user, not belonging to explanation of this Instruction Manual.
6. 6.     It is our goal to bring increased performance and greater value to these established products as quick as possible. Our company reserves the right to make changes without notice at any time.

Packing List

1. Principal Machine                                                           ×1

2.Controlling Box                                                         ×1

3. Sets of load weights                                                 ×1

4. Spatula                                                                              ×1

5. Photoswitch & Temperature Sensor                     ×1

6. Thermostatic (water) Jacket                                         ×1

  7. Latex Pipes 6×9                                                         2×1.5M

8. Power-Line Connection                                            ×1

9. Instruction                                                                    ×1

10Attached Disc ( Operation video & software )   ×2

Shanghai XianDai Environment Engineering Technique Co., Ltd

1、荷重砝码   2、落   棒   3、导   套

4、恒温水套    5、旋转挡板    6、光电开关

7、水平仪    8、固定螺母    9、调节螺钉

落棒粘度计外形图