称重传感器(中英)
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称重传感器简介Introduction to Load Cells
什么是称重传感器？What is load cell
称重传感器是将力转换为可测量的电信号输出的传感器。 尽管称重传感器种类繁多，但基于应变计的称重传感器是最常用的类型。
A load cell is a transducer which converts force into a measurable electrical output.
Although there are many varieties of load cells, strain gage based load cells are the
most commonly used type.
称重传感器发展历史
Load Cell History
在应变计称重传感器成为工业称重领域常用的称重方法之前，人们普遍使用机械杠杆秤。 机械秤可以称量从药丸到列车车厢的所有物品，只要适当校准和维护，即可保证足够的精度和可靠性。 其工作方式包括利用重量平衡机制或者检测由机械杠杆产生的力。 最早的预应变计测力传感器包括液压和气动两种设计。 1843 年，英国物理学家 Charles
Wheatstone 爵士发明了可测量电阻的电桥电路。 惠斯通电桥电路非常适用于测量应变计中的电阻变化。 尽管第一台粘贴式电阻丝应变计早在二十世纪四十年代就已开发出来，但直到现代电子技术蓬勃发展，这项技术才有了技术和经济可行性。 而从那时起，应变计就广泛地应用在机械秤和独立称重传感器中。 今天，除了某些实验室还在使用精密的机械天平外，应变计称重传感器已在称重行业占据了统治地位。 气动称重传感器有时应用在对本质安全性和安全卫生性要求较高的领域；液压称重传感器不需要电源，因此适用于远程应用。 应变计称重传感器可提供
0.03% 到 0.25% 的满量程精度，适用于几乎所有工业应用。
Before strain gage-based load cells became the method of choice for industrial weighing
applications, mechanical lever scales were widely used. Mechanical scales can weigh
everything from pills to railroad cars and can do so accurately and reliably if they are
properly calibrated and maintained. The method of operation can involve either the use
of a weight balancing mechanism or the detection of the force developed by mechanical
levers. The earliest, pre-strain gage force sensors included hydraulic and pneumatic
designs. In 1843, English physicist Sir Charles Wheatstone devised a bridge circuit that
could measure electrical resistances. The Wheatstone bridge circuit is ideal for
measuring the resistance changes that occur in strain gages. Although the first bonded
resistance wire strain gage was developed in the 1940s, it was not until modern
electronics caught up that the new technology became technically and economically
feasible. Since that time, however, strain gages have proliferated both as mechanical
scale components and in stand-alone load cells. Today, except for certain laboratories
where precision mechanical balances are still used, strain gage load cells dominate the
weighing industry. Pneumatic load cells are sometimes used where intrinsic safety and
hygiene are desired, and hydraulic load cells are considered in remote locations, as they
do not require a power supply. Strain gage load cells offer accuracies from within 0.03% to 0.25% full scale and are suitable for almost all industrial applications.
称重传感器性能比较
类型 称重范围 精度
(FS) 应用 优点 缺点
机械称重传感器
液压称重传感器 最高
10,000,000
lb 0.25% 罐体、箱体和漏斗。
危险区域。 作用广、
对温度不敏感。 昂贵、复杂。
气动称重传感器 范围广 高 食品行业、危险区域 本质安全。
不含液体。 响应速度慢。
需要清洁干燥的空气
应变计称重传感器弯梁式称重传感器 10-5k lbs. 0.03% 罐体、台秤 成本低、结构简单 应变计外露，
需要保护
剪切梁式称重传感器 10-5k lbs. 0.03% 罐体、台秤、
偏心负载 良好的抗侧能力，
密封性和防护性更佳
筒最高 500k 0.05% 卡可称量无水式称重传感器 lbs. 车、罐体、地秤和漏斗秤 移动负载 平负载保护
环形和薄饼形称重传感器 5- 500k
lbs. 罐体、箱体、秤 全不锈钢材质 不允许负载移动
按钮和垫圈式
称重传感器 0-50k lbs
0-200 lbs.（典型） 1% 小秤 体积小、价格低 负载必须居中放置，
不允许负载移动
其它称重传感器
螺旋形 0-40k lbs. 0.2% 平台、叉车、车轮载荷、
汽车座椅重量 可处理偏轴负载、
过载、震动
光纤 0.1% 电力传输
电不受
RFI/EMI
和 缆、螺柱或螺栓安装 高温影响，本质安全
压阻 0.03% 灵敏度极高，
高信号输出电平 成本高、非线性输出
称重传感器工作原理：Load Cell Operating Principles:
称重传感器的设计可按生成的输出信号类型（气动、液压、电气）或重量检测方式（弯梁、剪切梁、压力、张力等）区分。
Load cell designs can be distinguished according to the type of output signal generated
(pneumatic, hydraulic, electric) or according to the way they detect weight (bending,
shear, compression, tension, etc.)
液压称重传感器是一种力平衡设备，通过内部填充液体的压力变化测量重量。 在滚动隔膜式液压称重传感器中，作用在集料器上的负载或力将传递到活塞，进而压挤封闭在弹性隔膜腔中的填充液体。 力越大，液压液体的压力就越大。 此压力值可在本地指示，也可发送到其它位置，以实现远程指示或控制。 输出具有线性特性，相对来说不易受填充液体的容量和温度的影响。 如果称重传感器经过适当的安装和校准，则精度可达到满量程 0.25% 以内，适用于大多数的过程称重应用。 由于这种传感器不使用电气元件，因此非常适用于危险区域。 典型的液压称重传感器应用包括罐体、箱体和漏斗称重。 为了达到最高的精度，应在罐体的每个支撑点放置一个称重传感器，通过将这些传感器的输出求和，得出罐体的总重量。
Hydraulic load cells are force -balance devices, measuring weight as a change in
pressure of the internal filling fluid. In a rolling diaphragm type hydraulic load cell, a
load or force acting on a loading head is transferred to a piston that in turn compresses
a filling fluid confined within an elastomeric diaphragm chamber. As force increases, the
pressure of the hydraulic fluid rises. This pressure can be locally indicated or
transmitted for remote indication or control. Output is linear and relatively unaffected
by the amount of the filling fluid or by its temperature. If the load cells have been
properly installed and calibrated, accuracy can be within 0.25% full scale or better,
acceptable for most process weighing applications. Because this sensor has no electric
components, it is ideal for use in hazardous areas. Typical hydraulic load cell
