JPS6349175B2 - - Google Patents
Info
- Publication number
- JPS6349175B2 JPS6349175B2 JP56080869A JP8086981A JPS6349175B2 JP S6349175 B2 JPS6349175 B2 JP S6349175B2 JP 56080869 A JP56080869 A JP 56080869A JP 8086981 A JP8086981 A JP 8086981A JP S6349175 B2 JPS6349175 B2 JP S6349175B2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- casing
- diaphragm
- passage
- overpressure protection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000001514 detection method Methods 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 15
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 239000011800 void material Substances 0.000 claims 2
- 230000000694 effects Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
- G01L13/02—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements
- G01L13/025—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using diaphragms
Description
【発明の詳細な説明】
本発明は、過圧保護装置を内蔵する差圧伝送器
に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a differential pressure transmitter incorporating an overpressure protection device.
第１図に従来の差圧伝送器の一例を示す。同図
において、１，１′は被検出圧を導入する受圧フ
ランジ、２は本体ケーシング、２ａおよび２ｂは
弁座、３および３′は受圧ダイアフラム、４は半
導体感圧素子、５は過圧保護ベローズ、６および
６′は弁、７および７′はオーリング、８は過圧保
護ベローズ５の曲りを矯正するための板ばね、９
は過圧保護用補助ベローズ、１０および１０′は
シリコーン油などの封入液、Paは高圧側被検出
圧力、Pbは低圧側被検出圧力をそれぞれ示す。 FIG. 1 shows an example of a conventional differential pressure transmitter. In the figure, 1 and 1' are pressure receiving flanges that introduce the detected pressure, 2 is the main body casing, 2a and 2b are valve seats, 3 and 3' are pressure receiving diaphragms, 4 is a semiconductor pressure-sensitive element, and 5 is overpressure protection. Bellows, 6 and 6' are valves, 7 and 7' are O-rings, 8 is a leaf spring for correcting the bending of the overpressure protection bellows 5, 9
is an auxiliary bellows for overpressure protection, 10 and 10' are filled liquids such as silicone oil, P a is the pressure to be detected on the high pressure side, and P b is the pressure to be detected on the low pressure side, respectively.
いま、この差圧伝送器の高圧側に圧力Paが加
わつたとすると、過圧保護ベローズ５が圧縮さ
れ、弁６，６′は図示右方へ変位するとともに、
感圧素子４は差圧（Pa−Pb）に応じた信号を発
生する。さらに検出範囲を超える圧力が加わる
と、オーリング７が本体ケース２の弁座２ａに当
接する。これにより封入液１０′は受圧ダイアフ
ラム３′とオーリング７との間の部分と、オーリ
ング７と感圧素子４との間の部分とに分離され、
この両者間での封入液１０′の移動は阻止される。
さらに過大な圧力が加わると、オーリング７が圧
縮され、弁６の硬質な端面が弁座２ａに当接する
まで過圧保護ベローズ５が圧縮され、この時発生
する内圧は過圧保護用補助ベローズ９が変位する
ことにより吸収される。したがつて、感圧素子４
の両面に加わる圧力がバランスするので、感圧素
子４にはオーリング７が弁座２ａに当接した時以
上の差圧が加わることはない。過大な圧力が除去
されたときには、過圧保護ベローズ５は元に戻
る。低圧側に過大な圧力が加わつた場合も同様で
ある。 Now, if pressure P a is applied to the high pressure side of this differential pressure transmitter, the overpressure protection bellows 5 will be compressed, and the valves 6 and 6' will be displaced to the right in the figure.
The pressure sensitive element 4 generates a signal according to the differential pressure (P a −P b ). When a pressure exceeding the detection range is further applied, the O-ring 7 comes into contact with the valve seat 2a of the main body case 2. As a result, the sealed liquid 10' is separated into a part between the pressure receiving diaphragm 3' and the O-ring 7, and a part between the O-ring 7 and the pressure-sensitive element 4.
Movement of the filled liquid 10' between the two is prevented.
When excessive pressure is further applied, the O-ring 7 is compressed, and the overpressure protection bellows 5 is compressed until the hard end face of the valve 6 comes into contact with the valve seat 2a, and the internal pressure generated at this time is absorbed by the overpressure protection auxiliary bellows. It is absorbed by the displacement of 9. Therefore, the pressure sensitive element 4
Since the pressures applied to both sides of the valve are balanced, no pressure difference greater than when the O-ring 7 contacts the valve seat 2a is applied to the pressure-sensitive element 4. When the excessive pressure is removed, the overpressure protection bellows 5 returns to its original position. The same applies when excessive pressure is applied to the low pressure side.
しかしながら、この差圧伝送器には次のような
欠点がある。 However, this differential pressure transmitter has the following drawbacks.
〔１〕 ベローズを２個使用するため構造が複雑
になる。[1] The structure is complicated because two bellows are used.
〔２〕 過圧保護機能を確実にするためには、過
圧保護ベローズ５のばね定数を小さくし、且つ
有効面積を大きくし、圧力に対する変位量を大
きくして、オーリング７または７′と弁座２ａ
または２ｂとの間のクリアランスを大きくする
ことが望ましい。ところが実際には、受圧ダイ
アフラム３の体積変化率（単位圧力当りのダイ
アフラムの変位により排除される体積）とベロ
ーズ５の体積変化率（単位圧力当りのベローズ
の変位により排除される体積）の比が100：１
以下になると感圧素子に加わる差圧の精度に影
響を与える。したがつて、前記のクリアランス
は、実際には１mm以下になるためベローズ５の
ばね定数や加工精度のばらつきにより適正な圧
力で過圧保護機能を作動させるための調整作業
に時間がかかる。[2] In order to ensure the overpressure protection function, the spring constant of the overpressure protection bellows 5 should be made small, the effective area should be made large, and the amount of displacement with respect to pressure should be made large, so that the O-ring 7 or 7' Valve seat 2a
Or, it is desirable to increase the clearance between 2b and 2b. However, in reality, the ratio of the volume change rate of the pressure receiving diaphragm 3 (the volume removed by the displacement of the diaphragm per unit pressure) and the volume change rate of the bellows 5 (the volume removed by the displacement of the bellows per unit pressure) is 100:1
Below this, the accuracy of the differential pressure applied to the pressure sensitive element will be affected. Therefore, the above-mentioned clearance is actually less than 1 mm, and due to variations in the spring constant and processing accuracy of the bellows 5, it takes time to adjust the overpressure protection function in order to operate the overpressure protection function at an appropriate pressure.
〔３〕 オーリングの圧縮による永久歪や、熱に
よる膨張、収縮により前記クリアランスが最初
の設定値から変わり、その結果過圧保護作動圧
力が変わる恐れがある。[3] The clearance may change from the initial set value due to permanent deformation due to compression of the O-ring or expansion or contraction due to heat, and as a result, the overpressure protection operating pressure may change.
次に、従来の差圧伝送器の他の例を第２図に示
す。同図において、２１は本体ケーシング、２
２，２２′は受圧ダイアフラム、２３，２３′は調
節ダイアフラム、２４，２４′は円盤状片持ばね、
２５は高圧側封入液、２５′は低圧側封入液、２
６は高圧側封入液を連通させるキヤピラリーチユ
ーブ、２７は高圧側封入液を半導体感圧素子の高
圧側へ連通させるキヤピラリーチユーブ、２８は
低圧側封入液を連通させるキヤピラリーチユー
ブ、２９は低圧側封入液を半導体感圧素子の低圧
側へ連通させるキヤピラリーチユーブである。こ
の例のものでは、調節ダイアフラム２３，２３′
を円盤状片持ばね２４，２４′によつて予め撓ま
せておいて、撓みによる調節ダイアフラムの復元
力と円盤状片持ばねの復元力を釣合わせておく。
いま、高圧側に圧力Pcが加わると、調節ダイアフ
ラム２３および２３′が図示右方へ変位するが、
円盤状片持ばね２４，２４′の復元力により調節
ダイアフラム２３，２３′の体積変化率は受圧ダ
イアフラム２２および２２′の体積変化率にくら
べて極めて小さくできる。さらに、圧力Pcが検出
範囲を超えて加わると、受圧ダイアフラム２２が
ケーシングに形成されている波状のバツクアツプ
プレートに着座し、それ以上の過大圧が高圧側封
入液に加わることを防ぐ。この方式では、円盤状
片持ばね２４，２４′による予荷重の値を選ぶこ
とにより、検出範囲内の圧力では調節ダイアフラ
ム２３，２３′はほとんど変位せず、検出範囲を
超えた圧力が加わると調節ダイアフラム２３，２
３′が変位し始めるように設定できる。 Next, FIG. 2 shows another example of a conventional differential pressure transmitter. In the figure, 21 is the main body casing, 2
2, 22' are pressure receiving diaphragms, 23, 23' are adjustment diaphragms, 24, 24' are disc-shaped cantilever springs,
25 is the high pressure side filled liquid, 25' is the low pressure side filled liquid, 2
6 is a capillary reach tube that communicates the high pressure side filled liquid, 27 is a capillary reach tube that communicates the high pressure side filled liquid to the high pressure side of the semiconductor pressure sensitive element, 28 is a capillary reach tube that communicates the low pressure side filled liquid, 29 is a low pressure side This is a capillary reach tube that communicates the side-filled liquid to the low-pressure side of the semiconductor pressure-sensitive element. In this example, the adjusting diaphragms 23, 23'
is bent in advance by the disk-shaped cantilever springs 24, 24', and the restoring force of the adjustment diaphragm due to the bending is balanced with the restoring force of the disk-shaped cantilever spring.
Now, when pressure P c is applied to the high pressure side, the adjustment diaphragms 23 and 23' are displaced to the right in the figure.
Due to the restoring force of the disc-shaped cantilever springs 24, 24', the volume change rate of the adjusting diaphragms 23, 23' can be made extremely small compared to the volume change rate of the pressure receiving diaphragms 22, 22'. Further, when the pressure P c is applied beyond the detection range, the pressure receiving diaphragm 22 seats on the wavy backup plate formed in the casing, preventing further excessive pressure from being applied to the high-pressure side sealed liquid. In this method, by selecting the preload value of the disc-shaped cantilever springs 24, 24', the adjustment diaphragms 23, 23' will hardly displace when the pressure is within the detection range, and when the pressure exceeding the detection range is applied. Adjustment diaphragm 23,2
3' can be set so that it starts to be displaced.
しかしながら、この方式には次の欠点がある。 However, this method has the following drawbacks.
〔１〕 調節ダイアフラムが２枚必要であるこ
と。[1] Two adjustment diaphragms are required.
〔２〕 ２枚の調節ダイアフラムに同時に差圧を
加えるためにキヤピラリーチユーブにより接続
せねばならず、構造が複雑になる。[2] In order to simultaneously apply differential pressure to two adjustment diaphragms, they must be connected by a capillary reach tube, which complicates the structure.
本発明は、従来の差圧伝送器の過圧保護装置に
おける上述のような欠点を解消した過圧保護装置
を具えた差圧伝送器を提供することを目的とす
る。このため本発明では、第１圧力室（高圧側）
と第２圧力室（低圧側）とを隔離する１個の過圧
保護用ダイアフラムと、このダイアフラムの両面
とそれぞれ対向する第１および第２のケーシング
の端面との間に配設した一対の弾性部材とを用い
たのみで過圧保護装置を構成したことにより、構
造が簡単で、クリアランス調整などの必要のない
差圧伝送器を実現して所期の目的を達成した。 SUMMARY OF THE INVENTION An object of the present invention is to provide a differential pressure transmitter equipped with an overpressure protection device that eliminates the above-mentioned drawbacks of conventional overpressure protection devices for differential pressure transmitters. Therefore, in the present invention, the first pressure chamber (high pressure side)
one overpressure protection diaphragm that isolates the first and second pressure chambers (low pressure side); and a pair of elastic diaphragms disposed between both surfaces of this diaphragm and the opposing end surfaces of the first and second casings, respectively. By constructing an overpressure protection device using only the above members, a differential pressure transmitter with a simple structure and no need for clearance adjustment etc. was realized, and the desired purpose was achieved.
以下、本発明の実施例を図面を参照して説明す
る。第３図に本発明による差圧伝送器の一実施例
を示す。同図において、３１，３１′は被検出圧
を導入する第１および第２受圧フランジ、３２お
よび３２′は第１ケーシングおよび第２ケーシン
グで、互に対向した１端面の外周部で過圧保護用
ダイアフラム３４を液密に挾持している。互に対
向した１端面にはそれぞれ凹部３２ａおよび３
２′ａが形成されている。第１ケーシング３２お
よび第２ケーシング３２′の他端面は、それぞれ
波状のバツクアツププレート３２ｂおよび３２′
ｂに形成され、バツクアツププレート３２ｂおよ
び３２′ｂと適宜の空隙をおいてそれぞれ受圧ダ
イアフラム３３および３３′が液密に取着されて
いる。また、第１ケーシング３２および第２ケー
シング３２′には、受圧ダイアフラム３３および
３３′の内側の空隙と凹部３２ａおよび３２′ａと
を連通する通路３９および３９′がそれぞれ穿設
されている。 Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows an embodiment of a differential pressure transmitter according to the present invention. In the figure, 31 and 31' are first and second pressure receiving flanges that introduce the detected pressure, and 32 and 32' are a first casing and a second casing, and the outer periphery of one end face facing each other protects against overpressure. The diaphragm 34 is held in a liquid-tight manner. Concave portions 32a and 3 are formed on one end surface facing each other, respectively.
2'a is formed. The other end surfaces of the first casing 32 and the second casing 32' are wavy backup plates 32b and 32', respectively.
Pressure-receiving diaphragms 33 and 33' are fluid-tightly attached to the backup plates 32b and 32'b with appropriate gaps between them. Further, passages 39 and 39' are formed in the first casing 32 and the second casing 32', respectively, which communicate the spaces inside the pressure receiving diaphragms 33 and 33' with the recesses 32a and 32'a.
３７は第３ケーシングで、第１および第２ケー
シング３２，３２′にまたがつて突設され、その
内部を２分する如く感圧素子３５が装着されてい
る。３６は感圧素子３５の出力を取り出すリー
ド、３８はカバーである。そして、感圧素子３５
の一方の受圧面をかこむ室３７ａが第１ケーシン
グ３２内の通路３９と通路４０で連通され、感圧
素子３５の他方の受圧面と連通した室３７ｂが第
２ケーシング３２′内の通路３９′と通路４０′で
連通されている。第１ケーシング３２の空隙、通
路３９、凹部３２ａと第３ケーシング内の室３７
ａ、通路４０とで構成された第１圧力室および第
２ケーシング３２′の空隙、通路３９′、凹部３
２′ａと第３ケーシング内の室３７ｂ、通路４
０′とで構成された第２圧力室には、それぞれ封
入液が充填されている。 Reference numeral 37 denotes a third casing, which extends over the first and second casings 32, 32' and is provided with a pressure sensitive element 35 so as to divide the inside of the third casing into two. 36 is a lead for taking out the output of the pressure sensitive element 35, and 38 is a cover. And the pressure sensitive element 35
A chamber 37a surrounding one pressure-receiving surface of the pressure-sensitive element 35 is communicated with a passage 39 in the first casing 32 through a passage 40, and a chamber 37b communicating with the other pressure-receiving surface of the pressure-sensitive element 35 is connected to a passage 39' in the second casing 32'. It is communicated with by a passage 40'. Gap, passage 39, recess 32a in first casing 32 and chamber 37 in third casing
a, the first pressure chamber configured with the passage 40, the gap in the second casing 32', the passage 39', and the recess 3
2'a, chamber 37b in the third casing, passage 4
The second pressure chambers constituted by 0' and 0' are each filled with a sealed liquid.
４２，４２′は笠形ばねで、第４図および第５
図に示すように、中央の円板４２ａから複数の脚
４２ｂが傾斜を持つて放射状に突出し、各脚４２
ｂの先端が前記円板４２ａから適宜の寸法離隔し
た一平面上に位置する形状に形成されている。そ
して、笠形ばね４２は第１ケーシング３２の凹部
３２ａの底面に円板４２ａが同心的にねじ４３に
より固着され、その脚４２ｂの先端は過圧保護用
ダイアフラム３４の一方の面に当接している。ま
た、笠形ばね４２′は第２ケーシング３２′の凹部
３２′ａの底面に円板４２′ａが同心的にねじ４
３′により固着され、その脚４２′ｂの先端は過圧
保護用ダイアフラム３４の他方の面に当接してい
る。 42, 42' are cap-shaped springs, as shown in Figures 4 and 5.
As shown in the figure, a plurality of legs 42b protrude radially from a central disc 42a with an inclination, and each leg 42
The tip of b is formed in a shape such that the tip thereof is located on one plane at an appropriate distance from the disk 42a. In the cap-shaped spring 42, a disc 42a is concentrically fixed to the bottom surface of the recess 32a of the first casing 32 by screws 43, and the tips of the legs 42b are in contact with one surface of the overpressure protection diaphragm 34. . In addition, the cap-shaped spring 42' has a disk 42'a concentrically attached to the bottom surface of the recess 32'a of the second casing 32'.
3', and the tip of the leg 42'b is in contact with the other surface of the overpressure protection diaphragm 34.
次に、上記のように構成された本発明一実施例
の差圧伝送器の動作を説明する。いま、この差圧
伝送器の第１受圧フランジ３１から高圧側圧力
Pa、第２受圧フランジ３１′から低圧側圧力Pbが
加わつたとすると、Pa＞Pbであるから過圧保護
用ダイアフラム３４は図示右方へ変位するととも
に、感圧素子３５は差圧（Pa−Pb）に応じた信
号を発生する。さらに差圧（Pa−Pb）が検出範
囲を超えると、過圧保護用ダイアフラム３４はさ
らに右方へ変位し、その移動容積分だけ受圧ダイ
アフラム３３，３３′は図示右方へ変位し、高圧
側の受圧ダイアフラム３３は第１ケーシング３２
のダイアフラム対向面に形成されたバツクアツプ
プレート３２ｂに着座する。これにより、それ以
上の圧力が高圧側から加わつても第１ケーシング
内部の封入液には圧力は伝達されず、感圧素子３
５が保護される。Pb＞Paの場合も上述と全く同
様に低圧側の受圧ダイアフラム３３′がバツクア
ツププレート３２′ｂに着座して感圧素子３５を
過大圧力から保護する。 Next, the operation of the differential pressure transmitter according to an embodiment of the present invention configured as described above will be explained. Now, the high pressure side pressure is being transmitted from the first pressure receiving flange 31 of this differential pressure transmitter.
Assuming that P a and low pressure side pressure P b are applied from the second pressure receiving flange 31', the overpressure protection diaphragm 34 is displaced to the right in the figure, and the pressure sensitive element 35 is Generates a signal according to the pressure (P a - P b ). Furthermore, when the differential pressure (P a - P b ) exceeds the detection range, the overpressure protection diaphragm 34 is further displaced to the right, and the pressure receiving diaphragms 33, 33' are displaced to the right in the figure by the displacement volume, The pressure receiving diaphragm 33 on the high pressure side is connected to the first casing 32
It is seated on a backup plate 32b formed on the opposite surface of the diaphragm. As a result, even if more pressure is applied from the high pressure side, the pressure is not transmitted to the liquid sealed inside the first casing, and the pressure sensitive element 3
5 is protected. When P b > P a , the pressure receiving diaphragm 33' on the low pressure side is seated on the backup plate 32'b to protect the pressure sensitive element 35 from excessive pressure, just as described above.
過圧保護用ダイアフラム３４は、次のような動
作をすることが理想的である。即ち、差圧（Pa
−Pb）が検出範囲内の値であるときは、圧力に
対する体積変化率が小さく（剛性が高く）、検出
範囲を超えると急激に圧力に対する体積変化率が
大きくなればよい（即ち、剛性が急激に低下すれ
ばよい）。このような動作を実現できれば、検出
範囲内の差圧の出力特性に影響を与えることな
く、確実な過圧保護動作を与えることができる。
本発明では、笠形ばね４２，４２′を用いて前述
の理想的な過圧保護動作に近い動作を与えてい
る。即ち、第６図、第７図は共に過圧保護用ダイ
アフラム３４と笠形ばね４２，４２′の動作の説
明図で、第６図は高圧側、低圧側とも同一の圧力
P0が加わつたときの状態を示し、第７図は、高
圧側の圧力がP0からP1（P1＞P0）になつたときの
状態を示す。第６図においては、差圧がゼロのと
きは笠形ばね４２，４２′はともに過圧保護用ダ
イアフラム３４に中心からの半径r0の位置で脚の
先端が当接している。ところが第７図のように
P1＞P0の差圧が加わると、過圧保護用ダイアフ
ラム３４は図示右方へ変位しようとするため、笠
形ばね４２はダイアフラム３４から離れ、笠形ば
ね４２′はダイアフラム３４から接線方向の力を
受けてダイアフラム面上を移動して半径r1の位置
で当接するようになる。過圧保護用ダイアフラム
３４の圧力による移動容積は、有効面積即ち笠形
ばね４２′とダイアフラム３４との当接位置が半
径の増大する方向に移動していくに従つて増大し
てくる。第８図に過圧保護用ダイアフラム３４の
移動容積と差圧との関係曲線を表わす。破線は笠
形ばねがない場合を示し、実線は笠形ばね４２，
４２′を用いた場合を示す。この２本の曲線を比
較すると明らかなように、笠形ばねがない場合に
くらべ、笠形ばねを用いた場合は、検出圧力範囲
Ａにおいては移動容積が小さく、検出圧力範囲を
超えると移動容積が急激に増加しており、前述の
理想的な過圧保護動作に近づくことがわかる。な
お、図中Ｂは受圧ダイアフラムの着座範囲を示
す。 Ideally, the overpressure protection diaphragm 34 operates as follows. That is, the differential pressure (P a
-P b ) is within the detection range, the rate of change in volume with respect to pressure is small (high stiffness), and when the detection range is exceeded, the rate of change in volume with respect to pressure suddenly increases (i.e., stiffness is high). (It only needs to drop rapidly.) If such an operation can be realized, reliable overpressure protection operation can be provided without affecting the output characteristics of the differential pressure within the detection range.
In the present invention, the cap-shaped springs 42, 42' are used to provide an operation close to the ideal overpressure protection operation described above. That is, both FIG. 6 and FIG. 7 are explanatory diagrams of the operation of the overpressure protection diaphragm 34 and the cap-shaped springs 42, 42', and FIG. 6 shows the same pressure on both the high pressure side and the low pressure side.
The state when P 0 is applied is shown, and FIG. 7 shows the state when the pressure on the high pressure side changes from P 0 to P 1 (P 1 >P 0 ). In FIG. 6, when the differential pressure is zero, the ends of the legs of both the cap-shaped springs 42 and 42' are in contact with the overpressure protection diaphragm 34 at a position of radius r 0 from the center. However, as shown in Figure 7
When a differential pressure of P 1 > P 0 is applied, the overpressure protection diaphragm 34 tends to displace to the right in the figure, so the cap-shaped spring 42 separates from the diaphragm 34, and the cap-shaped spring 42' receives a tangential force from the diaphragm 34. It moves on the diaphragm surface and comes into contact at a position with radius r1 . The displacement volume of the overpressure protection diaphragm 34 due to pressure increases as the effective area, that is, the contact position between the cap-shaped spring 42' and the diaphragm 34 moves in the direction of increasing radius. FIG. 8 shows a relationship curve between the moving volume of the overpressure protection diaphragm 34 and the differential pressure. The broken line shows the case without the cap-shaped spring, and the solid line shows the case without the cap-shaped spring 42,
42' is used. As is clear from comparing these two curves, when using a cap-shaped spring, the moving volume is smaller in the detection pressure range A, compared to the case without the cap-shaped spring, and the moving volume increases rapidly when the detection pressure range is exceeded. , which approaches the ideal overpressure protection operation described above. Note that B in the figure indicates the seating range of the pressure receiving diaphragm.
以上のような過圧保護動作を行なう本発明一実
施例の差圧伝送器は次のような効果を有する。 The differential pressure transmitter according to one embodiment of the present invention that performs the above-described overpressure protection operation has the following effects.
〔１〕 過圧保護用ダイアフラムは１枚でよく、
構造が簡単である。[1] Only one diaphragm is required for overpressure protection.
The structure is simple.
〔２〕 検出範囲内での過圧保護用ダイアフラム
の剛性が高いので、同範囲内での圧力〜出力特
性に影響を与えない。[2] Since the overpressure protection diaphragm has high rigidity within the detection range, it does not affect the pressure-output characteristics within the same range.
〔３〕 検出範囲を超える過圧が加わると、過圧
保護用ダイアフラムの剛性が低くなるので、受
圧ダイアフラムとバツクアツププレートとの間
の空隙は厳しく押える必要がない。[3] When an overpressure exceeding the detection range is applied, the rigidity of the overpressure protection diaphragm decreases, so there is no need to tightly suppress the gap between the pressure receiving diaphragm and the backup plate.
〔４〕 高圧室（第１圧力室）と低圧室（第２圧
力室）を対称の構造にできる。[4] The high pressure chamber (first pressure chamber) and the low pressure chamber (second pressure chamber) can have symmetrical structures.
次に、第９図に本発明による差圧伝送器の変形
例を示す。この変形例のものでは、笠形ばね５
１，５１′がそれぞれその円板を過圧保護用ダイ
アフラム３４の中心に固定され、脚の先端が第１
ケーシング５２のダイアフラム３４に対向した面
５２ａおよび第２ケーシング５２′のダイアフラ
ム３４に対向した面５２′ａにそれぞれ当接して
いる。面５２ａ，５２′ａは過圧保護用ダイアフ
ラム３４の変位によつて笠形ばね５１，５１′の
脚の先端が面の半径方向に移動し易いような曲面
に形成されている。この変形例のものでは、笠形
ばね５１，５１′の剛性を差圧に応じて変化させ
る（差圧が小さいときに剛性が大きく、差圧が大
きいときに剛性が小さい）ことによつて過圧保護
用ダイアフラム３４の体積変化率を制御している
が、結果的には第３図の実施例のものと同等の効
果を得ることができる。 Next, FIG. 9 shows a modification of the differential pressure transmitter according to the present invention. In this modification, the cap-shaped spring 5
1 and 51' are each fixed with its disk at the center of the overpressure protection diaphragm 34, and the tip of the leg is connected to the first
They are in contact with a surface 52a of the casing 52 facing the diaphragm 34 and a surface 52'a of the second casing 52' facing the diaphragm 34, respectively. The surfaces 52a, 52'a are formed into curved surfaces such that the tips of the legs of the cap-shaped springs 51, 51' can easily move in the radial direction of the surfaces as the overpressure protection diaphragm 34 is displaced. In this modified example, the rigidity of the cap-shaped springs 51, 51' is changed according to the differential pressure (the rigidity is large when the differential pressure is small, and the rigidity is small when the differential pressure is large) to prevent overpressure. Although the volume change rate of the protective diaphragm 34 is controlled, the same effect as that of the embodiment shown in FIG. 3 can be obtained as a result.
なお、第３図および第９図の実施例では第４図
および第５図に示したような笠形ばねを用いた
が、同等な効果を奏する弾性部材ならば笠形ばね
に限定されるものではない。また、上述の実施例
では受圧ダイアフラムが過圧時にケーシングのバ
ツクアツププレートに着座する構造にしたが、こ
れに限らず、例えばオーリング等によつて受圧ダ
イアフラムの動きを封止するような構造でもよ
い。 In the examples shown in FIGS. 3 and 9, cap-shaped springs as shown in FIGS. 4 and 5 are used, but the cap-shaped springs are not limited to any other elastic member that provides the same effect. . Further, in the above embodiment, the pressure receiving diaphragm is structured to sit on the back-up plate of the casing when overpressurized, but the structure is not limited to this, and a structure in which the movement of the pressure receiving diaphragm is sealed with an O-ring or the like may also be used. good.
以上詳述したように本発明によれば、構造が簡
単で厳しい寸法の調整を要せず、検出範囲内では
出力特性に影響を与えずしかも過圧時に確実な過
圧保護機能を果たし、長期にわたつて測定精度を
維持する差圧伝送器を提供することができる。 As detailed above, according to the present invention, the structure is simple, does not require severe dimensional adjustment, does not affect the output characteristics within the detection range, and performs a reliable overpressure protection function in the event of overpressure. It is possible to provide a differential pressure transmitter that maintains measurement accuracy over time.
第１図は従来の差圧伝送器の一例を示す断面
図、第２図は従来の差圧伝送器の他の例を示す断
面図、第３図は本発明による差圧伝送器の一実施
例を示す断面図、第４図および第５図はそれぞれ
笠形ばねの平面図および側面図、第６図および第
７図は過圧保護用ダイアフラムと笠形ばねとの動
作説明図で、第６図は差圧がゼロの状態を、第７
図は差圧が加わつた状態をそれぞれ示す図、第８
図は過圧保護用ダイアフラムの移動容積と差圧と
の関係を示すグラフ、第９図は本発明による差圧
伝送器の他の実施例を示す断面図である。
１，１′…受圧フランジ、２…本体ケーシング、
２ａ，２ｂ…弁座、３，３′…受圧ダイアフラム、
４…感圧素子、５…過圧保護ベローズ、６，６′
…弁、７，７′…オーリング、８…板バネ、９…
補助ベローズ、１０，１０′…封入液、２１…本
体ケーシング、２２，２２′…受圧ダイアフラム、
２３，２３′…調節ダイアフラム、２４，２４′…
片持ばね、２５，２５′…封入液、２６，２７，
２８，２９…キヤピラリーチユーブ、３１…第１
受圧フランジ、３１′…第２受圧フランジ、３２
…第１ケーシング、３２′…第２ケーシング、３
２ａ，３２′ａ…凹部、３２ｂ，３２′ｂ…バツク
アツププレート、３３，３３′…受圧ダイアフラ
ム、３４…過圧保護用ダイアフラム、３５…感圧
素子、３６…リード、３７…第３ケーシング、３
７ａ…感圧素子の一方の受圧面を囲む室、３７ｂ
…感圧素子の他方の受圧面と連通した室、３８…
カバー、３９，３９′…通路、４０，４０′…通
路、４１，４１′…オーリング、４２，４２′…笠
形ばね、４２ａ…円板、４２ｂ…脚、５１，５
１′…笠形ばね、５２…第１ケーシング、５２′…
第２ケーシング、５２ａ…第１ケーシングの過圧
保護用ダイアフラムに対向した面、５２′ａ…第
２ケーシングの過圧保護用ダイアフラムに対向し
た面。
FIG. 1 is a sectional view showing an example of a conventional differential pressure transmitter, FIG. 2 is a sectional view showing another example of a conventional differential pressure transmitter, and FIG. 3 is an implementation of a differential pressure transmitter according to the present invention. A sectional view showing an example, FIGS. 4 and 5 are respectively a plan view and a side view of the cap-shaped spring, and FIGS. 6 and 7 are explanatory diagrams of the operation of the overpressure protection diaphragm and the cap-shaped spring. is the state where the differential pressure is zero, and the seventh
The figures show the states in which differential pressure is applied.
The figure is a graph showing the relationship between the moving volume of the overpressure protection diaphragm and the differential pressure, and FIG. 9 is a sectional view showing another embodiment of the differential pressure transmitter according to the present invention. 1, 1'...Pressure flange, 2...Main casing,
2a, 2b... Valve seat, 3, 3'... Pressure receiving diaphragm,
4...Pressure sensitive element, 5...Overpressure protection bellows, 6, 6'
... Valve, 7,7'... O-ring, 8... Leaf spring, 9...
Auxiliary bellows, 10, 10'... Filled liquid, 21... Main body casing, 22, 22'... Pressure receiving diaphragm,
23, 23'...adjustment diaphragm, 24, 24'...
Cantilever spring, 25, 25'...Filled liquid, 26, 27,
28, 29... Capillary reach tube, 31... 1st
Pressure receiving flange, 31'...Second pressure receiving flange, 32
...First casing, 32'...Second casing, 3
2a, 32'a... recess, 32b, 32'b... back-up plate, 33, 33'... pressure receiving diaphragm, 34... overpressure protection diaphragm, 35... pressure sensitive element, 36... lead, 37... third casing, 3
7a...A chamber surrounding one pressure-receiving surface of the pressure-sensitive element, 37b
...A chamber communicating with the other pressure-receiving surface of the pressure-sensitive element, 38...
Cover, 39, 39'... Passage, 40, 40'... Passage, 41, 41'... O-ring, 42, 42'... Cap-shaped spring, 42a... Disc, 42b... Leg, 51, 5
1'... Cap-shaped spring, 52... First casing, 52'...
Second casing, 52a...A surface facing the overpressure protection diaphragm of the first casing, 52'a...A surface facing the overpressure protection diaphragm of the second casing.
Claims (1)
に挟んで一端面が対向しそれぞれの対向端面に凹
部を有するとともにそれぞれの他端面に空隙をお
いて受圧ダイアフラムが液密に取着された第１ケ
ーシングおよび第２ケーシングと、前記空隙と凹
部とを連通してこれらの各ケーシングに穿設され
た通路と、前記第１および第２ケーシングにまた
がつて突設された第３ケーシング内を２分する如
く装着され一方の受圧面をかこむ室が第１ケーシ
ング内の通路と通路により連通されるとともに他
方の受圧面と連通した室が第２ケーシング内の通
路と通路により連通された感圧素子と、前記第１
ケーシングの空隙・通路・凹部と第３ケーシング
内の感圧素子の一方の受圧面をかこむ室・第１ケ
ーシングの通路に至る通路とで構成された第１圧
力室および前記第２ケーシングの空隙・通路・凹
部と第３ケーシング内の感圧素子の他方の受圧面
に連通した室・第２ケーシングの通路に至る通路
とで構成された第２圧力室にそれぞれ封入された
封入液と、前記第１ケーシングの受圧ダイアフラ
ムが取着された端面に液密に取着され導圧口を有
する第１受圧フランジと、前記第２ケーシングの
受圧ダイアフラムが取着された端面に液密に取着
され導圧口を有する第２受圧フランジと、前記過
圧保護用ダイアフラムとこのダイアフラムに対向
する第１および第２ケーシングの各端面との間に
それぞれ介挿設置され差圧による過圧保護用ダイ
アフラムの変位に応じてこのダイアフラムの圧力
に対する体積変化率を差圧が検出範囲内にあると
き小さく、検出範囲を超えたとき大きくなるよう
に制御する弾性部材とを具備してなる差圧伝送
器。 ２ 弾性部材が、中央の円板から複数の脚が傾斜
を持つて放射状に突出し各脚の先端が前記円板か
ら適宜の寸法離隔した一平面上に位置する形状の
笠形ばねに形成され、この笠形ばねがその円板を
第１および第２ケーシングの過圧保護用ダイアフ
ラムに対向する各端面にそれぞれ同心的に固着さ
れ、複数の脚の先端を過圧保護用ダイアフラムの
表面にそれぞれ当接させて配設されたことを特徴
とする特許請求の範囲第１項記載の差圧伝送器。 ３ 弾性部材が、中央の円板から複数の脚が傾斜
を持つて放射状に突出し各脚の先端が前記円板か
ら適宜の寸法離隔した一平面上に位置する形状の
笠形ばねに形成され、この笠形ばねがその円板を
過圧保護用ダイアフラムの表裏各面にそれぞれ同
心的に固着され、複数の脚の先端を第１および第
２ケーシングの過圧保護用ダイアフラムに対向す
る各端面にそれぞれ当接させて配設されたことを
特徴とする特許請求の範囲第１項記載の差圧伝送
器。 ４ 過大差圧が加わつた際に過圧保護用ダイアフ
ラムの変位により受圧ダイアフラムがそれぞれ対
向する第１ケーシングまたは第２ケーシングの端
面に形成されたバツクアツププレートのいずれか
一方に着座するように空隙を設定したことを特徴
とする特許請求の範囲第１項乃至第３項のいずれ
か一項に記載の差圧伝送器。[Scope of Claims] 1. The overpressure protection diaphragm is liquid-tightly sandwiched between the outer peripheries of the end faces, one end face is opposite to the other end face, and each opposing end face has a recess, and the other end face is provided with a gap so that the pressure receiving diaphragm is liquid-tight. a first casing and a second casing attached to the casing, a passage bored in each of these casings to communicate the gap and the recess, and a passage provided protruding across the first and second casings. The interior of the third casing is installed so as to be divided into two parts, and a chamber surrounding one pressure receiving surface is communicated with a passage in the first casing, and a chamber communicating with the other pressure receiving surface is communicated with a passage in the second casing. the pressure sensitive element communicated with the first
A first pressure chamber consisting of a void/passage/recess in the casing, a chamber surrounding one pressure receiving surface of a pressure-sensitive element in the third casing, and a passage leading to the passage in the first casing, and a void/passage in the second casing. A liquid sealed in a second pressure chamber formed of a passage/recess, a chamber communicating with the other pressure-receiving surface of the pressure-sensitive element in the third casing, and a passage leading to the passage in the second casing; A first pressure receiving flange is fluid-tightly attached to the end face of the second casing to which the pressure receiving diaphragm is attached and has a pressure guiding port; A second pressure receiving flange having a pressure port is inserted between the overpressure protection diaphragm and each end face of the first and second casings facing the diaphragm, and displacement of the overpressure protection diaphragm due to differential pressure is provided. and an elastic member that controls the volume change rate of the diaphragm with respect to pressure so that it is small when the differential pressure is within the detection range and becomes large when the differential pressure exceeds the detection range. 2. The elastic member is formed into a cap-shaped spring having a plurality of legs protruding radially with an inclination from a central disk, with the tip of each leg being located on a plane with an appropriate distance from the disk; A cap-shaped spring has its disc concentrically fixed to each end face of the first and second casings facing the overpressure protection diaphragm, and has the tips of the plurality of legs abut against the surfaces of the overpressure protection diaphragms, respectively. 2. The differential pressure transmitter according to claim 1, wherein the differential pressure transmitter is arranged as follows. 3. The elastic member is formed into a cap-shaped spring having a plurality of legs protruding radially with an inclination from a central disk, the tip of each leg being located on one plane at an appropriate distance from the disk; The cap-shaped spring has its discs fixed concentrically to each of the front and back surfaces of the overpressure protection diaphragm, and the tips of the plurality of legs are in contact with each end surface of the first and second casings facing the overpressure protection diaphragm. The differential pressure transmitter according to claim 1, wherein the differential pressure transmitter is arranged in contact with the transmitter. 4 Create a gap so that when an excessive differential pressure is applied, the pressure receiving diaphragm is seated on either one of the backup plates formed on the opposing end faces of the first casing or the second casing due to the displacement of the overpressure protection diaphragm. The differential pressure transmitter according to any one of claims 1 to 3, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8086981A JPS57196128A (en) | 1981-05-29 | 1981-05-29 | Differential pressure transmitting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8086981A JPS57196128A (en) | 1981-05-29 | 1981-05-29 | Differential pressure transmitting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57196128A JPS57196128A (en) | 1982-12-02 |
| JPS6349175B2 true JPS6349175B2 (en) | 1988-10-03 |
Family
ID=13730344
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8086981A Granted JPS57196128A (en) | 1981-05-29 | 1981-05-29 | Differential pressure transmitting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57196128A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0243424U (en) * | 1988-09-20 | 1990-03-26 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6073426A (en) * | 1983-09-30 | 1985-04-25 | Toshiba Corp | Differential pressure transmitter |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52148181A (en) * | 1976-05-03 | 1977-12-09 | Honeywell Inc | Differential pressure transmitter |
| JPS56129832A (en) * | 1980-02-13 | 1981-10-12 | Honeywell Inc | Differential pressure transmitter |
-
1981
- 1981-05-29 JP JP8086981A patent/JPS57196128A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52148181A (en) * | 1976-05-03 | 1977-12-09 | Honeywell Inc | Differential pressure transmitter |
| JPS56129832A (en) * | 1980-02-13 | 1981-10-12 | Honeywell Inc | Differential pressure transmitter |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0243424U (en) * | 1988-09-20 | 1990-03-26 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57196128A (en) | 1982-12-02 |
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