Name: manometers and gauges for fluid pressure
Uploaded: 2025-02-13T15:43:11.000Z
Duration: 1 min 16 s
Channel: JoVE

流体圧力は、チューブ内の液体カラムを使用して、垂直またはマノメーターと呼ばれる傾斜で測定されます。液柱の高さが圧力差を決定します。
最も単純な圧力計は、圧力を測定するために使用されるピエゾメータチューブです。これは、上部が開いてコンテナに接続されている垂直チューブで、同じ流体を使用してチューブ内の圧力を示します。
また、一般的に使用される圧力計は、U字型のチューブを流体源に結合したU字型チューブからなるU字型圧力計です。これにはゲージ流体と呼ばれる別の流体が含まれており、圧力が測定されている流体と混ざりません。
傾斜管圧力計は、片方の脚が傾斜しており、測定された流体と混ざらないゲージ流体が含まれており、圧力差が傾斜に沿って読み取られ、感度が向上します。
U字管および傾斜管の圧力計は、システム内の2つのコンテナまたはポイント間の圧力差を測定するために一般的に使用されます。
その他の圧力計には、流体やガスの圧力を測定するブルドンゲージや、大気圧を測定するアネロイド気圧計などがあります。

流体圧力の測定

Measurement of Fluid Pressure

流体圧力は、通常、圧力差を示すために液体柱を利用するマノメータと呼ばれる装置を使用して測定されます。マノメータ内の液体柱の高さは、流体によって加えられる圧力を反映し、シンプルでありながら効果的な測定手段を提供します。マノメータの種類はそれぞれ、構成と使用される流体の種類に基づいて特定の目的に使用されます。

 マノメータの基本的な形式は、ピエゾメータです。これは、上部が開いていて、圧力を測定するのと同じ流体で満たされた垂直管です。流体容器に接続すると、管内の流体の高さは、容器内の圧力と直接相関します。より複雑な用途では、U 字管マノメータは、測定対象の流体と混ざらないゲージ液で満たされた U 字型の管を使用します。この設定により、2 点間の差圧測定が可能になります。

 もう 1 つのバリエーションは、片方の脚が傾斜している傾斜管マノメータです。この傾斜脚は、測定スケールを傾斜に沿って伸ばすことで感度を高め、小さな圧力差を正確に読み取ることができます。

 マノメータ以外にも、流体圧力や大気圧を測定するツールはあります。たとえば、ブルドン圧力計はさまざまな産業用途でガスや液体の圧力を測定するために広く使用されています。一方、アネロイド気圧計は大気圧を測定し、天気予報や高度測定によく使用されます。

流体圧力は、チューブ内の液体カラムを使用して、垂直またはマノメーターと呼ばれる傾斜で測定されます。液柱の高さは...

Education

JoVE Core

Civil Engineering

土木工学

Unit 1

ユニット1

Fluid Statics

流体静力学

KEY TERMS AND CONCEPTS

主要用語と概念

manometers and gauges for fluid pressure

Fluid pressure is measured with manometers and related gauges. These tools use a liquid column to show pressure differences. The height of the column gives a simple reading of the force the fluid exerts.

A basic manometer is the piezometer. It is a vertical tube that is open at the top and filled with the same fluid being measured. When the tube connects to a container, the fluid height in the tube matches the pressure inside that container.

For more detailed measurements, the U-tube manometer is used. It has a U-shaped tube filled with a gauge fluid that does not mix with the fluid being measured. This setup is useful for measuring the pressure difference between two points.

The inclined-tube manometer is another form of manometer. One leg of the tube is tilted. This incline makes the scale stretch out, so it is easier to read very small pressure differences.

Other pressure tools are also used in practice. The Bourdon gauge measures gas or liquid pressure in many industrial settings. The aneroid barometer measures atmospheric pressure and is used in weather forecasting and altitude measurements.

Manometers and Gauges for Fluid Pressure

concept of pressure at a point

Fluid Pressure at One Point

Fluid pressure at one point is the focus of this lesson. It shows that pressure in a fluid is the same in every direction at a single location. This happens because fluid molecules move randomly and collide with nearby molecules in a balanced way. At a given point, the pressure depends on the surrounding fluid molecules. It is affected by depth and density, not by the shape of the container or the way the fluid is oriented. In a fluid at rest, the pressure acts equally in all directions...

basic equation for pressure field

Pressure Balance in a Fluid Element

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pressure variation in a fluid at rest

Hydrostatic Pressure and Fluid Depth

Hydrostatic pressure describes how pressure changes with depth in a fluid at rest. In a stationary fluid, the fluid acceleration is zero, so the forces inside the fluid balance. That means pressure at a point below the surface depends on depth, not on the container’s shape or size. Only vertical forces affect the pressure change in this situation. These forces come from the weight of the fluid above a point. When pressure is compared at two different levels, the difference in pressure equals...

measurement of fluid pressure

Fluid pressure is measured with manometers and related gauges. These tools use a liquid column to show pressure differences. The height of the column gives a simple reading of the force the fluid exerts. A basic manometer is the piezometer. It is a vertical tube that is open at the top and filled with the same fluid being measured. When the tube connects to a container, the fluid height in the tube matches the pressure inside that container. For more detailed measurements, the U-tube...

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hydrostatic-pressure-force-on-a-plane-surface

Hydrostatic Pressure on Submerged Surfaces

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hydrostatic pressure force on a curved surface

hydrostatic-pressure-force-on-a-curved-surface

Finding the Force on Curved Fluid Surfaces

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buoyancy and stability for submerged and floating bodies

buoyancy-and-stability-for-submerged-and-floating-bodies

How Buoyancy Keeps Bodies Stable in Water

Buoyancy and stability explain how submerged and floating bodies behave in a fluid. When a body is fully or partly under water and stays still, the fluid pushes upward on it. That upward push is called the buoyant force. The buoyant force acts through the center of buoyancy. This is the center of the displaced fluid volume. Archimedes’ principle says the buoyant force equals the weight of the fluid displaced by the body. Stability describes whether a body can return to its original position...

design example: application of archimedes' principle

design-example-application-of-archimedes-principle

Floating Block Buoyancy and Center of Buoyancy

Archimedes' principle is used to analyze the buoyant force on a wooden block that floats in seawater. The block has a rectangular section, and its dimensions, specific gravity, and the specific weight of seawater are used in the calculation. This setup shows how floating bodies stay in equilibrium. The first step is to find the weight of the block from its volume and specific gravity. Then Archimedes' principle is applied. The weight of the displaced water must equal the weight of the block.

key terms and concepts

Learn how piezometers, U-tube and inclined manometers, Bourdon gauges, and aneroid barometers measure fluid and atmospheric pressure in practical settings.

Manometers and Gauges for Fluid Pressure | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Manometers and Gauges for Fluid Pressure

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