• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:

    公开号:SE1001046A1
    申请号:SE1001046
    申请日:2010-10-25
    公开日:2012-04-26
    发明作者:Per Wikefeldt
    申请人:Nordisk Ind Ab；
    IPC主号:
    专利说明:

    Known technology for measuring high RF The following technology is known in meteorology.
    When using moisture meters containing so-called resistive RF sensors, the air temperature in the vicinity of the RF sensor can be raised, and thus RF lowered, by the heat that is generated, when current flows through the RF sensor. By resistive RF sensor is meant a sensor, whose electrical resistance or conductance varies greatly with RF. In this way, the RF sensor is prevented from being damaged by high RF. However, measurement of high RF is not made possible in this way.
    A common way to measure high RF is as follows. A moisture meter is placed in a heated chamber and air, the RF of which is to be measured, is supplied and flows through the chamber. As a result of the heating, the RF of the chamber air is reduced. The RF of the supplied air is calculated with knowledge of the difference between the temperature of the chamber air and the temperature of the supplied air.
    The problem The above known techniques have not been transferred to moisture measurement in concrete. There are several possible reasons why this is the case. The need for an additional temperature sensor for measuring the temperature of chamber air complicates and makes it more expensive (one is always available to measure the temperature of undisturbed concrete). It is important to measure temperature differences, fractions of a degree C large, and this requires, for example, two temperature sensors of the same type and with very little mutual difference in properties (a temperature increase of 1 C lowers RF by as much as 6% units). Another reason may be the requirement that moisture meters must have the same temperature as the concrete, see "Manual Moisture Measurement in Concrete" mentioned above. The reason for this is the strong temperature dependence of RF. Another reason may be that heating is expected to require so much power, that battery operation avi the measuring equipment included electronics is practically impossible.
    Principle solution It turns out that the three above-mentioned obstacles, which are associated with known technology, can be overcome in the manner described below. According to accepted principle, a hole (1) is drilled in the concrete, usually with a diameter of 16 mm and a depth of 50 - 300 mm, see figure 1, which is a cross section of a moisture meter mounted in concrete. An airtight cavity (2) in the lower part of the borehole is formed by the casing (3), the sealing ring (4), the sealing plug (5) and a free concrete surface in the bottom (6) of the borehole. The gap between the pipe (3) and the inside of the borehole is also sealed in the upper end of the borehole (not shown in figure 1). i / led concrete RF means RF inside the cavity when stationary.
    What follows is characteristic of the invention.
    Preferably, a resistive, self-heated RF sensor is selected to avoid a component that only heats air.
    By surrounding, in whole or in part, the self-heated RF sensor (7) in figure 1 with a heat-insulating housing (8), it is achieved that the free concrete surface (6) has a temperature undisturbed by the self-heating. The casing has an insulating effect mainly because its material has low thermal conductivity, by preventing air flow (convection) and by a combination of both. However, the wall of the housing (8) must in some way be moisture-permeable. One way (of several conceivable) is that moisture diffuses between cavities (2) and the interior of the housing (8) through an opening, possibly several such, (9) in the housing. A steady state occurs when the partial pressure of the water vapor is the same on either side of the opening (9). The cross-sectional area of the opening can be small, because the RF in the cavity changes so slowly that moisture exchange between the cavity and the interior of the casing can still take place quickly enough.
    By suitable choice of dimensions and materials, the housing (8) in Figure 1 can be given an insulating ability, called k, which is reproducible in terms of production (that is, the variation of k in the manufacture of a plurality of moisture meters is small). k is the temperature increase inside the housing per developed power inside. Thus, the power applied to the RF sensor (7) determines the difference between, on the one hand, the temperature of air inside the housing (8 yo and, on the other hand, the temperature of air in the cavity (2). it is measured with the temperature sensor (10).
    By achieving high k-values, the supplied power can be kept so low that battery operation of the measuring equipment's electronics is possible. The value of k is determined by a type calibration of the device, i.e. k is an apparatus constant. 3 Construction examples within the framework of the described principle solution, a number of constructions are of course conceivable. An example of a functional, industrially feasible construction is shown here.
    The example is based on the Swedish patent specification 8900979-9 "Conductivity cell and method of producing one". The conductivity cell is marketed as an RF sensor in the HumiGuard measurement system. The patent specification describes an RF sensor which contains a hygroscopic electrolyte. Electrolytes are not damaged by self-heating for a long time, provided that the applied voltage lacks a direct voltage component. Small hysteresis is another benefit that comes with hygroscopic electrolyte.
    The housing (8) in figure 1 contains an RF sensor (7), from the measuring system i-lumiGuard, whose electrodes (11) are connected to the conductor (12) sealing plug (5).
    The temperature sensor (10) is a thermistor, the resistance of which varies greatly with temperature. The switches (12) and (13) connect RF sensors (7) and temperature sensors (10) to conductance meters.
    The housing (8) is made, for example, of rigid cellular plastic with closed cells, the thermal conductivity of which is low. Polyethylene and polypropylene foam have the advantage of being hydrophobic, non-hygroscopic and of being able to be made with a smooth surface. These properties prevent moisture from being absorbed by the material of the casing or condensing on its surface. The opening (9) can be, for example, a tube, which is pressed through the wall of the housing. Alternatively, the casing is made of rigid, homogeneous material, such as polypropylene, possibly supplemented with an outer fibrous, more heat-insulating material of polyethylene.
    The sealing ring (4) and the sealing plug (5) are made, for example, of rubber. The electrodes of the RF sensor (11) are thin to minimize heat conduction.
    Cellulose with closed cells is elastic and vapor-tight, which properties mean that the housing (8) can be designed (enlarged) to seal against the cavity (2). The sealing plug (5) is then superfluous and possibly also the sealing ring (4) and the casing (3).
    Some measurement examples - the height and diameter of the RF sensor (7) are 15 and 3 mm, respectively, the inner diameter of the tube (3) 14 mm. f / RF of air in the cavity (2) is RF = rf + kP arm / dr = ff + / <uzs arna / dr, where rf and t are RF and temperature of air inside the casing respectively (8 l. k is the insulating capacity of the casing (8).
    P = UZS is the developed power in the RF sensor (7), where U is applied voltage across the RF sensor and S is its conductance. d (rf) / dt is practically independent of RF and temperature and is set to 6.0% RF / C. In general, its value is calculated using a table of saturation pressure for water vapor at different temperatures. In the HumiGuard measuring system, rf is calculated by a computer program using the conductivity measurement values of the RF sensor (7) and the thermistor (10).
    The program is modified so that the RF is calculated according to the previous equation.
    Test The previous construction has been tested using an experimental model, which mimics the device in Figure 1. The free concrete surface (6) is replaced by (simulated with) an ampoule, containing water or aqueous solution of glycerol.
    It can generate the intended RF in the cavity (2). The casing (8) consists of an inner part of homogeneous polypropylene, outer diameter 6 mm and wall thickness 1 mm, and an outer part of polypropylene fibers. The cross-sectional area of the opening (9) is 0.5 mmz. k is measured at 0.3 C / mW, as an average of measurements with a number of housings of the same type and a number of RF sensors of the same type. k is obtained from the previous equation.
    RF in the cavity (2) was maintained at 100, 99 and 98% by means of ampoules.
    The measurement results of the experimental model are shown in Figure 2. Its RF sensor was calibrated at 85% RH, when the measurement began, and at 100% RH four days later.
    It is desirable to be able to minimize power consumption. RF sensors according to the HumiGuard measuring system can withstand up to 98% RF, and are therefore suitably connected to (constant) voltage for self-heating, only when the RF in the cavity (2) is in the range 98 ~ 100%. Under these conditions, the power consumption is around 1 mW. If the voltage is regulated as required during a drying process, in such a way that the RF is not allowed to exceed 98% inside the housing (8), the power consumption is less than that. Batteries with the required capacity are available.
    权利要求:
    Claims (9)
    [1]
    Device for measuring high relative humidity inside material consisting of sensors for relative humidity (7), which is completely or partially surrounded by moisture-permeable housing (8), characterized in that it comprises device for direct or indirect measurement of the inside housing (8) generated the heat output and knowledge of the insulation capacity of the casing.
    [2]
    Device according to the preceding claim, characterized in that the sensor for relative humidity (7) is self-heated.
    [3]
    Device according to one of the preceding claims, characterized in that moisture transport can take place through at least one opening (9) in the housing (8).
    [4]
    Device according to one of the preceding claims, characterized in that the cover (8) is wholly or partly made of cellular plastic.
    [5]
    Device according to one of the preceding claims, characterized in that the housing (8) is negligibly hygroscopic.
    [6]
    Device according to one of the preceding claims, characterized in that the housing (8) seals against a cavity (2). The cavity borders upwards towards the casing and downwards towards the material.
    [7]
    Device according to one of the preceding claims, characterized in that the sensor for relative humidity (7) contains a hygroscopic electrolyte.
    [8]
    Device according to any one of the preceding claims, characterized in that the sensor for relative humidity comprises a sock of an electrically non-conductive material braided around a cylindrical core of non-electrical material and at least two electrodes (11) in the form of spaced wires from each other and extend substantially parallel to each other and parallel to the axis of the core, that the fibers of the sock are tensile biased, so that the sock abuts the warp threads and that the sock is soaked with a hygroscopic electrolyte.
    [9]
    Method of measuring high RF inside material with device according to any one of the preceding claims, characterized in that relative humidity inside the material is determined on the basis of measurement, which comprises measuring relative humidity of air inside the housing (8) and of the inside height ( 8) generated the heat effect.
    类似技术:
    公开号 | 公开日 | 专利标题
    CN108445309A|2018-08-24|A kind of temperature gradient disc insulator surface charge measuring device and method off field
    JP6473524B2|2019-02-20|System and method for measuring thermal properties of rocks under high pressure conditions
    US20200326075A1|2020-10-15|Automatic oven with humidity sensor
    CN106570289A|2017-04-19|Contact temperature rise measurement method of low-voltage electric appliance under large current on the basis of finite element analysis
    SE1001046A1|2012-04-26|Apparatus and methods for measuring relative humidity within materials
    JP2011219173A5|2014-04-24|
    CN104236739A|2014-12-24|Temperature and humidity sensor
    CN201464397U|2010-05-12|Field detecting device for heat transfer coefficient of building envelope
    US9091583B2|2015-07-28|Fluid level sensor system and method
    CN206228335U|2017-06-09|A kind of ear temperature meter with heating function
    CN204228291U|2015-03-25|A kind of measurement mechanism of diaphragm closed pore temperature and system
    CN110849929B|2020-08-14|Method for monitoring release state of sensor with suspension structure
    CN203786579U|2014-08-20|Thermostatic oil bath
    CN103217231B|2015-04-22|Fiber Bragg grating temperate sensor for oil-immersed transformer
    CN204228300U|2015-03-25|A kind of encapsulating structure demarcated for thermistor temp coefficient
    CN104459411A|2015-03-25|Double-cavity transformer thermal ageing real-time simulation measuring device and application thereof
    CN107014511B|2019-12-31|Point heat source temperature testing method incapable of being in direct contact
    US8720255B2|2014-05-13|Water uptake measurement system
    CN105043595A|2015-11-11|Calibrator for transformer thermometer
    CN107290381B|2019-09-13|A kind of measuring device and method of the nano wire thermal conductivity based on T-shaped structure
    CN103196572A|2013-07-10|Method for improving main transformer remote-reading thermometer accuracy and remote-reading thermometer
    CN204154855U|2015-02-11|A kind of electrical strength measurement mechanism of insulating material
    CN106885947A|2017-06-23|A kind of resistance meter
    Lee et al.2015|Flexible four-in-one micro sensor for reliability and 100-hour durability testing
    CN205719323U|2016-11-23|A kind of multipoint temperature measuring circuit of electronic equipment
    同族专利:
    公开号 | 公开日
    SE535237C2|2012-06-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    AT517846A4|2015-12-14|2017-05-15|Technische Universität Wien|Indicator device for building material moisture determination|
    法律状态:
    2018-05-29| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1001046A|SE535237C2|2010-10-25|2010-10-25|Apparatus and methods for measuring relative humidity within materials|SE1001046A| SE535237C2|2010-10-25|2010-10-25|Apparatus and methods for measuring relative humidity within materials|
    [返回顶部]