SU530209A1

SU530209A1 - Differential pressure sensor

Info

Publication number: SU530209A1
Application number: SU2110926A
Authority: SU
Inventors: Владимир Рубенович Варданян; Сергей Зармоевич Мамян
Original assignee: Ереванский политехнический институт им.К.Маркса
Priority date: 1975-03-06
Filing date: 1975-03-06
Publication date: 1976-09-30

Description

1one

Изобретение относитс к области конт рольно-измерительной техники, в частности к датчикам разности давлений.The invention relates to the field of control and measuring equipment, in particular to pressure difference sensors.

Известны датчики разности давлений, содержащие мембрану, соединенную с трансформаторным преобразователем деформации 1.Эти датчики имеют недостаточную точность при измерении нестационарных давлений.Differential pressure sensors are known that contain a membrane connected to a deformation transformer converter 1. These sensors have insufficient accuracy in measuring non-stationary pressures.

По основному авт. св. Ne 344303 известен датчик разности давлений, содержащий корпус, в котором закреплены два манометрических чувствительных элемента, например плоские мембраны, и упругий коль девой элемент с преобразователем деформаНИИ в электрический сигнал, включенным в систему автогенератора и выполненным в виде пьезорезонатора, закрепленного в упругом кольцевом элементе так, что его рабоча ось расположена соосно с осью одной из мембран, перпендикул рной к оси другой мембраны, а упругий кольцевой элемент установлен в корпусе на шариковых опорах.According to the main author. St. Ne 344303 is a pressure differential sensor, comprising a case in which two gauge sensitive elements, for example flat membranes, are fixed, and an elastic ring element with a strain gauge converter into an electrical signal included in the oscillator system and made in the form of a piezoresonator fixed in an elastic ring element that its working axis is located coaxially with the axis of one of the membranes, perpendicular to the axis of the other membrane, and the elastic ring element is mounted in the housing on ball bearings.

При изменении температуры частота собственных колебаний пьезорезонатора также измен етс и увеличиваетс температурна погрешность измерений.As the temperature changes, the natural frequency of the piezoresonator also changes and the temperature measurement error increases.

С целью уменьшени вли ни температуры на результаты измерений перпендикул рно оси пьезорезонатора в упругом кольцевом элементе закреплен дополнительный пьезорезонатор, электрически соединенный с преобразователем его деформации в электрический сигнал.In order to reduce the effect of temperature on the measurement results perpendicular to the axis of the piezoresonator, an additional piezoresonator, electrically connected to the converter of its deformation into an electrical signal, is fixed in the elastic ring element.

Преобразователь деформации дополнительного пьезорезонатора в электрический сигнал может быть вьшопнен в виде автогенератора .The converter of deformation of an additional piezoresonator into an electrical signal can be expressed as an oscillator.

Кроме того, преобразователь деформации дополнительного пьезорезонатора в элерический сигнал может быть выполнен в виде пьезоэлектрического фильтра, соединенного с выходом автогенератора.In addition, the strain transducer of the additional piezoresonator into the electric signal can be made in the form of a piezoelectric filter connected to the output of the auto-oscillator.

На фиг. 1 представлен датчик разности давлений в разрезе; на фиг. 2 и 3 - блоксхемы аппаратуры дл проведени с его помощью измерений.FIG. 1 shows a differential pressure sensor in section; in fig. 2 and 3 are block diagrams of apparatus for measuring with its help.

Claims

Two flat membranes 2 and 3 are fixed in the housing 1, transmitting pressures F and Pj of the medium being measured through ball bearings 4 to an elastic ring element 5 in which piezoresonators 6 and 7 are fixed. The working axis of the piezoresonator 6 is perpendicular to the plane of the membrane 2 and parallel to the plane of the membrane 3 and the working axis of the piezo resonator 7 is perpendicular to the plane of the membrane 3 and parallel to the plane of the membrane 2. In the diagram in FIG. 2 piezoresonators 6 and 7 are included in oscillators 8 and 9 connected to mixer 10. The output of mixer 1O is connected to the input of the partial detector 11 connected to the recorder 12. In the circuit in FIG. 3 piezoresonator b is included in the auto-oscillator 8, and piezoresonator 7 is included in the piezoelectric filter 13 connected to the output of the auto-oscillator 8. The output of the filter 13 is connected to the input of the amplitude detector 14 connected to the recorder 12. Under the action of the pressure difference P - P the piezoresonator 6 is compressed and the piezoresonator 7 is expanded. The frequency of their natural oscillations increases and decreases accordingly. When the temperature changes, the frequencies of the piezoresonators 6 and 7 also change, but the changes have the same signs and, with the axisymmetric shape of the elastic ring piezoelectric element and the same parameters, the piezoresonators 6 and 7 are close in magnitude. In the diagram in FIG. 2, the frequency components of the signal, caused by the effects of temperature change, are mutually compensated in the difference signal of the mixer 10 and the signal connected to the input of the recorder 12 is associated only with the value of the pressure difference in FIG. 3 Compensation of near temperature occurs due to the same frequency shift of the natural frequency of oscillation of the piezoresonator 6 and the passband of the piezoelectric filter 13. Using the additional piezoresonator with the working axis, perpendicular to the axis of the piezoresonator, and an additional deformation converter into the electric signal allows the sensor to expand the temperature range differential pressure and improve measurement accuracy. The invention 1. Pressure differential sensor according to the author. St. X 344303, characterized in that, in order to reduce the effect of temperature change on the measurement results, an additional piezoresonator is mounted perpendicular to the axis of the piezoresonator in the elastic ring element, electrically connected to the converter of its deformation into an electrical signal.

2. The sensor according to claim 1, that is, that the strain transducer of the additional piezoresonator into the electrical signal is made in the form of an auto-oscillator.

3. The sensor according to claim 1, characterized in that the converter of the deformation of the additional piezoresonator into the electric signal is made in the form of a piezoelectric filter connected to the output of the self-oscillator. Sources of information taken at the examination: 1. Ageikin DI, Kostin E.N. Kuznetsova N.N. Sensors of control and regulation, M., Mashinostroenie, 1965, p. 594.