RU2311622C1 - Method of setting sensor in temperature gage and temperature gage - Google Patents

Abstract

FIELD: measuring technique.

SUBSTANCE: method comprises setting the quartz sensor in the temperature gage inside a protecting sleeve and connecting its leads to the frequency generator with wires. The quartz resonator is positioned so that its leads face the bottom of the sleeve. The device has housing secured inside the pipelined by means of a setting head. The housing is connected with the protecting sleeve that receives thermosensitive element made of a quartz resonator. The leads of the resonator are connected to the circuit of the frequency generator through the wires. The frequency generator is mounted on the printed circuit mounted inside the housing. The quartz resonator is mounted inside the sleeve so that its leads face the sleeve bottom. The space between the quartz resonator and wall of the sleeve is filled with a heat conducting material. The top section of the housing is covered with a lid made of a material with low conductivity.

EFFECT: enhanced precision.

2 cl, 2 dwg

Description

The invention relates to thermometry, namely to contact temperature sensors, and can be used when measuring temperature with a minimum immersion depth of the sensor in the oil, chemical industry and utilities, in particular, in pipes of small diameter.

The closest in technical essence to the claimed are the temperature sensor and the sensor installation method used in it, presented in the materials described in the thematic catalog "Temperature Sensors", 2002, No. 2, issue 2, p. 46, and also used in CJSC PG Metran and are presented in the technical documentation SPGK 7050.110.00 Thermal converters Metran-299 dated 06.25.04.

A known method of installing a quartz resonator is that it is placed in a protective sleeve so that its conclusions are removed from the bottom of the sleeve.

In this case, the heat removal point (terminals) is removed from the heat-sensitive point - the bottom of the sleeve - and the measurement accuracy decreases. In addition, the main heat flux to the resonator does not pass through the zonal surface of the metal sleeve, but through the leads and the heat pick-up point is higher than the heat-sensitive point, which reduces the effective length of the immersion probe (sensor), which is very important with a small immersion depth.

The known sensor comprises a carrier tube (housing) fixed in the pipeline by means of a mounting head with a cap in the upper part, connected in its lower part by a threaded connection to a sleeve, in which a thermosensitive element is mounted, which is a quartz resonator placed by leads in the direction opposite to the bottom of the sleeve , and included in the leads in the circuit of the frequency generator assembled on a printed circuit board located in the carrier tube. In this case, the free space between the quartz resonator and the inner wall of the sleeve is filled with heat-conducting material, the mounting head and sleeve are made of metal and have an internal thread, and the carrier tube (case) has an external thread and is made of plastic. The circuit board is connected to external circuits via cable.

With the indicated arrangement of the quartz resonator in the sleeve, the main heat flux passes to the resonator not through the zone surface of the metal sleeve, but through the leads and the heat-sensitive point (heat removal point) is located above the resonator, i.e. far enough from the measuring point, which reduces the effective length of the sensor acting as an immersion probe, and reduces the accuracy of measurements.

The objective of the proposed technical solution is to reduce the length of the probe (immersion) and increase the accuracy of measurements.

The problem is solved in that:

- in the method of installing the sensing element, which is a quartz resonator, in the temperature sensor, namely, that the quartz resonator is placed in a protective sleeve, according to the invention, the quartz resonator is placed in the sleeve so that its terminals face the bottom of the sleeve.

- in a temperature sensor comprising a body with an external thread fixed in the pipeline by means of an installation head, closed at the top by a lid and connected at the bottom with a metal thermowell, in which a thermosensitive element is mounted, which is a quartz resonator, the terminals of which are connected via wires to the circuit of the frequency generator assembled on a printed circuit board located in the housing, according to the invention, the quartz resonator is mounted in the sleeve in such a way that the attachment points to it are vodov facing the bottom of the pockets.

Placing the quartz sensor with the leads down to the bottom of the sleeve, as it were, increases the length of the immersed part by the length of the body of quartz without actually increasing the length of the probe. The installation of a quartz resonator with leads to the bottom of the liner reduces the temperature gradient with the medium being measured, i.e. the temperature of the quartz leads approaches the temperature of the medium being measured and becomes less dependent on the heat flux leaving the probe (probe) outward, which increases the measurement accuracy. The "tip" of the thermometer, and not the entire submersible part, becomes the most sensitive zone (as in all thermometers). The above is also a technical result. The inventive method of installing the sensor and the temperature sensor with the sensor installed in this way are novel in comparison with the prototype, differing from it by the location of the quartz leads at the bottom of the sleeve, ensuring the achievement of a given result — providing a shorter probe length and improving measurement accuracy.

The applicant does not know the technical solutions possessing the indicated distinguishing features, ensuring the achievement of the specified result, therefore, he considers that the claimed group of inventions meets the criterion of "inventive step".

The claimed technical solutions can find wide application in thermometry, namely in the chemical, oil industry, and public utilities when used in sensors with a short immersion length for measuring temperature in pipes of small diameter, and therefore meet the criterion of "industrial applicability".

The claimed invention is illustrated by drawings, where shown in:

- figure 1 - the construction of the temperature sensor in the context;

- figure 2 - sectional design of a quartz resonator.

The inventive method consists in the fact that the quartz resonator is placed in a protective sleeve with leads to the bottom of the sleeve and connect its conclusions using wires with a frequency generator.

The temperature sensor (Fig. 1) contains, for example, a mounting head 1, a housing 2 and a protective sleeve 3, made in the form of a single all-metal construction, in which a thermosensitive element 4 is located, which is a quartz resonator connected by terminals 5 to the circuit of a frequency generator 6 located on the printed circuit board 7. In this case, the quartz resonator 4 is placed by the terminals 5 to the bottom of the sleeve 3. Between the quartz resonator 4 and the wall of the sleeve 3 the space is filled with heat-conducting material 8. The housing 2 has an external thread. The upper part of the housing is closed by a cover 9 made of a material with low thermal conductivity.

When this quartz resonator 4 is made as follows (see figure 2). It consists of a metal sleeve-casing 10, inside which a vacuum is created or inert gas is located and a quartz element 11 is placed, made, for example, in the form of a plate or in the form of a tuning fork. Pads 12 are attached to the upper part of the quartz element 11, to which the leads 5 are soldered. On top of the metal sleeve 10 is closed by a glass stopper 13.

The temperature sensor operates as follows.

When placing the sensor in a medium whose temperature it is to measure, the protective metal sleeve 3 is heated, while the heat is removed from the terminals 5 located at the bottom of the sleeve in a place whose temperature is as close as possible to the measured medium temperature. Moreover, in the quartz resonator itself, the main heat flux passes to the resonator 11 not through the metal sleeve-case 10, but through the terminals 5 and the heat-sensitive point is located at the very end of the immersion part, increasing its effective length.

Since the thermal conductivity of the glass stopper 13 and inert gas is orders of magnitude lower than the thermal conductivities of the metal leads (in the case of vacuum, the heat transfer is due to the radiation of the walls of the sleeve and the heat transfer is even lower), this solution provides a much smaller temperature gradient with the measured medium compared to the prototype and decreases the influence of heat flow on the conclusions to the environment, which together allows you to increase the accuracy of the measurement and reduce the dependence of the measurement error on ambient temperature.

Compared with the prototype of the claimed invention provide a more accurate temperature measurement with a shorter probe length.

Claims (2)

1. The method of installing a quartz sensor in a temperature sensor, which consists in the fact that the quartz resonator is placed in a protective sleeve and connect its conclusions using wires with a frequency generator, characterized in that the quartz resonator is placed leads to the bottom of the sleeve. 2. A temperature sensor comprising a housing fixed in a pipeline using an installation head and connected to a thermowell in which a thermosensitive element is mounted, which is a quartz resonator, the leads of which are connected via wires to a frequency generator circuit assembled on a printed circuit board located in the housing, characterized in that the quartz resonator is mounted in the sleeve in such a way that its terminals face the bottom of the sleeve.

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