Digital Microscopes
Observation and Measurement of Piping Joints and Valves Using a Digital Microscope
Factories are built with various pipes used to carry a wide variety of liquids and gases.
Joints and valves are used to connect these pipes and to control the fluids within. This section introduces observation and measurement examples of piping joints and valves using a digital microscope.
Piping joint and valve–related terms
- Fluid
The liquid or gas that flows through piping. - Joints
Components that connect pipes to other pipes, valves, and other parts. Joints can be used to change the direction of piping, branch or combine piping, change piping thickness, extend piping, or close off the ends of piping. - Valves
Used to adjust the amount, direction, and pressure of fluid flowing through piping. Typical valve types include globe valves, ball valves, gate valves, and butterfly valves. - Pressure loss
The decrease in momentum of a fluid flowing through piping. Pressure loss can occur if the shape or direction of flow changes when passing through a valve or joint.
Types of joints
Socket
Joints that connect to the external threads of a pipe.
Nipple
Joints that connect to the internal threads of a pipe.
Union
Joints that connect to the external threads of two pipes.
T
Joints that connect to the external threads of two pipes to create a T-shaped branch for connecting a third pipe.
Cross
Joints that connect to the external threads of four pipes to create a 4-way branch.
Elbow
Joints that connect to the external threads of two pipes to create a 90-degree bend.
Street elbow
Joints that connect to the external threads of one pipe and the internal threads of another pipe to create a 90-degree bend.
Bushing
Joints that connect to the internal threads of one pipe and the external threads of another pipe with a different diameter. The internal threads of the pipe with the larger diameter are connected to the external threads of the pipe with the smaller diameter.
Cap
Joints that connect to the external threads of a pipe to create an end cap.
Plug
Joints that connect to the internal threads of a pipe to create an end plug.
Types of valves
Globe valve
Globe valves have a spherical valve housing and is sometimes called a stop valve.Fluid flows along an S-shaped path that is stopped by a valve body that is pressed against the gap in the center. Opening and closing the valve requires turning the handle, which takes longer than other methods but allows for flow rate adjustments. This type is commonly used in water faucets.
Closed
A : Fluid flow
Open
Gate valve
Gate valves use a plate-shaped valve body that vertically divides the flow channel to stop the flow. These valves are used only to open or close the flow path and do not allow for flow rate adjustments. Opening and closing the valve requires turning the handle, which can take longer than other methods, and the vertical dimension of the valve is larger than that of other valve types. Gate valves are commonly used to stop the flow of water in water drainage mains and plant piping.
Closed
A : Fluid flow
Open
Ball valve
Ball valves include a ball-shaped valvebody that rotates inside the valve housing to open or close the flow channel. The flow channel is opened when the through-hole is oriented along the flow path, and closed when it is oriented at a right angle to the flow path. Because the lever only needs to be rotated 90 degrees, opening and closing ball valves can be done quickly, and the straight flow path created ensures low resistance characteristics. This type of valve is commonly used as a main gas valve.
Closed
A : Fluid flow
Open
Butterfly valve
Butterfly valves include a disc-shaped valve body in the valve housing that is rotated 90 degrees to open or close. Not only can the valve be opened or closed quickly, but these valves also offer excellent flow rate adjustment. The structure is also simple and does not require much installation space, making it commonly used in various situations.
Closed
A: Fluid flow
Open
Piping connection methods
Threaded
Joints and valves that are screwed into a pipe can be divided into two categories: those with tapered threads and those with parallel threads. These types are mainly used for small-diameter, low-pressure piping at normal temperatures.
Tapered thread
A : Female thread B : Male thread C : Taper
Parallel thread
A : Female thread B : Male thread
Flanged
With a flanged connection, the connection points are secured together using nuts and bolts. This type of connection can be used in a wide range of applications, including both small and large diameters as well as low and high pressures.
Socket welded
Socket welded connections are formed by inserting one pipe into the female connection of a joint or valve and welding the two together. This type of connection is used for high-temperature, high-pressure applications to help prevent leakage.
Butt welded
Butt welding secures the pipe and the joint or valve by welding the ends together. To ensure a strong weld, the ends are beveled first. This type of connection is used for high-temperature, high-pressure applications to help prevent leakage.
Typical piping materials
- Iron pipes (black)
Black iron pipes can be used for water, oil, steam, air, and various other fluids. - Iron pipes (white)
White iron pipes are hot dip galvanized to help prevent rust and corrosion. - Brass
Brass is a gold-colored alloy of copper and zinc. One common use for this material is water piping for flushable toilets. - Bronze
This dull gold-colored material is an alloy of copper, tin, zinc, lead, and other materials. Bronze is stronger, harder, and more resistant to rust than brass. - Stainless steel (SUS)
Stainless steel is a popular material for its excellent corrosion and heat resistance as well as durability. - Polyvinyl chloride (PVC)
This gray material is inexpensive and offers excellent versatility and strength. PVC is commonly used as water supply and drainage piping.
Observation and measurement examples of piping, joints, and valves using a digital microscope
The latest examples of observation and measurement of piping, joints, and valves using KEYENCE’s VHX Series 4K Digital Microscope are introduced below.
Observation of the inner wall of a joint
VH-Z20, 30×, ring illumination (normal image)
Glare removal + Depth composition image
The glare removal and depth composition functions enable clear observation of the inner walls of joints with all surfaces in focus.
Observation of the inner wall of a valve
VH-Z00, 30×, ring illumination
The VH-Z00 can be used to check for burrs on the inner wall of a valve at an observation distance of 95 mm (3.74").
2D measurement of flaws on the inner wall of a valve
VH-Z00, 50×, multi-lighting illumination
The multi-lighting function can be used to visualize even minute surface scratches.
Depth composition of the inner surface of piping
ZS-20, 30×, ring illumination image
A : Without depth composition B : With depth composition
3D shape measurement of the shot-blasted surface inside piping
VH-Z20, 200×, ring illumination image
3D shape measurement of weld lines on a PVC joint
VH-Z20, 200×, ring illumination image
3D shape measurement of machined surfaces of a valve
ZS-200, 1000×, coaxial partial illumination image
VHX-E100, 150×, ring illumination (normal image)
Observation of the surface of a valve
Optical Shadow Effect Mode image
Optical Shadow Effect Mode color map image
Optical Shadow Effect Mode can be used to visualize surface irregularities.
