PL79978B2

PL79978B2 -

Info

Publication number: PL79978B2
Application number: PL16677873A
Authority: PL
Priority date: 1973-11-24
Filing date: 1973-11-24
Publication date: 1975-08-30

Description

Element we¬ wnetrzny 3 jest wykonany w postaci walca drazonego czesciowo z obu stron i posiadajacego rowki 4 usytuowane symetrycznie w plaszczyznach bocznych.Zasadniczym elementem termometru z termooporem pneumatycznym jest termoopór pneumatyczny RT.Termoopór ten umieszczony jest w jednej galezi mostka pneumatycznego zasilanego sprezonym powietrzem o cisnieniu Po (fig. 1). Do zasilania ukladu moga byc równiez uzyte inne media. Praca w mostku zapewnia urzadzeniu kompensacje zmian cisnienia zasilania i atmosferycznego. Zaleznosc opornosci pneumatycznej termo- oporu od temperatury zwiazana jest ze zjawiskiem rozszerzalnosci cieplnej cial stalych. Obudowa 1 i 2 termo- oporu (fig. 2) wykonana jest z materialu o innym wspólczynniku rozszerzalnosci cieplnej, niz element we¬ wnetrzny 3. W wyniku przyrostu temperatury róznica miedzy srednica wewnetrzna obudowy 1 i 2, a srednica elementu wewnetrznego 3 maleje, co powoduje przyrost opornosci pneumatycznej termoopóru. Wzrost tej opornosci pociaga za soba zwiekszenie cisnienia mierzonego w punkcie WT, a tym samym rosnie róznica cisnien PT - P1, mierzonych odpowiednio w punktach WT, W1 (fig. 1). Rowki 4 usytuowane symetrycznie jw plaszczyz nach bocznych elementu 3 zapewniaja zmiane opornosci pneumatycznej jedynie na powierzchni roboczej, która ¦ jest pobocze walca o dlugosci I (fig. 3). Zaokraglenia o promieniu R w miejscach doprowadzenia 1a i odprowa¬ dzenia 2a powietrza z termooporu umozliwiaja zachowanie przeplywu o charakterze lawinarnym na jak najwiek¬ szej czesci drogi strumienia w termooporze. Wydrazenie elementu 3 ma na celu zmniejszenie stalej czasowej termooporu. PL PLThe internal element 3 is made in the form of a cylinder partially coated on both sides and has grooves 4 situated symmetrically in the side planes. The main element of the thermometer with pneumatic thermocouple is the pneumatic thermocouple RT. This resistance is placed in one branch of the pneumatic bridge fed with compressed air under pressure. After (Fig. 1). Other media may also be used to power the system. Working in the bridge allows the device to compensate for changes in supply and atmospheric pressure. The dependence of the air resistance of the thermoresistance on the temperature is related to the phenomenon of thermal expansion of solids. The housing 1 and 2 of the thermocouple (Fig. 2) is made of a material with a different coefficient of thermal expansion than the inner element 3. As a result of the increase in temperature, the difference between the inner diameter of the casings 1 and 2 and the diameter of the inner element 3 decreases, which causes an increase in the pneumatic resistance of the thermocouple. The increase in this resistance entails an increase in the pressure measured at the WT point, and hence the pressure difference PT - P1, measured at the WT, W1 points, respectively (Fig. 1). The grooves 4 situated symmetrically in the planes of the side sides of the element 3 ensure the change of the pneumatic resistance only on the working surface, which is the shoulder of the roller with the length I (Fig. 3). The roundings of the radius R in the places of the inlet 1a and the evacuation 2a of the air from the thermocouple allow the preservation of the avalanche-like flow over the largest possible part of the flow path in the thermocouple. The enhancement of element 3 is aimed at reducing the thermocouple time constant. PL PL

Claims

1. Patent claim A thermometer with a pneumatic thermal resistance used to carry out measurements of static temperatures in the range from -200 ° C to 1000 ° C, characterized by the fact that it has a cylindrical housing composed of two parts (1 and 2) tightly connected with each other with a fine thread, and the casing has endings allowing for air inlet (1a) and outlet (2a), while inside the casing there are roundings with radius (R) and the internal element (3) has a recess reducing the time constant and grooves (4) distributed symmetrically in side planes KL. 42i, 10/20 79 978 MKP G01k 11/00 £ r% l H \ - /? G / Wr f 'R l / l \ zzzz zz1 Vq 1 S ^ U D - //////, ^ Ra 2 Ko 5 OR IbLiNlA Urzedu Potentov * ego PL PL