The Yoshitake 150L-F plain type sight glass is designed to permit visual checking of fluid flow inside a pipe. It is widely used for equipment protection and process control in manufacturing facilities. Featuring a ductile cast iron body and hardened glass, it allows the user to monitor the mixed state, color, or intermittent flow of non-dangerous fluids such as cold and hot water or oil.

Features

• Two-component fluid can be checked by its color or mixed state.
• Intermittent fluid flow can be checked.
• Can be connected to either horizontal or vertical piping.
• The sight glass is available in ductile cast iron, accommodating a wide range of applications.
• Can be applied to steam condensate when equipped with optional mica plates.

Specifications

Specification	Value
Model	150L-F
Type	Plain
Application	Cold and hot water, Oil, Other non-dangerous fluids
Nominal Size	65A–150A
Maximum Working Pressure	1.0 MPa
Temperature Range	5–150°C
Max. Thermal Shock	100°C
Body Material	Ductile cast iron
Glass Material	Hardened glass
Connection	JIS 10K FF flanged

INFO

Available with mica plate for steam condensate applications. When used with a mica plate, the maximum allowable working pressure is 0.6 MPa. The glass part is considered a consumable part.

Dimensions and Weights

Nominal Size	d	L (mm)	W (mm)	Weight (kg)
65A	65	235	97	14.7
80A	73	235	97	15.1
100A	100	277	130	26.5
125A	125	336	155	36.8
150A	140	380	165	60.5

Structure and Materials

No.	Name of Parts	Material
1	Body	Ductile Cast Iron (FCD450)
2	Cover	Ductile Cast Iron (FCD450)
3	Glass	Tempered Glasses
4	Gasket	Non-Asbestos
5	Nut	Rolled Steel (SS400)
6/7	Bolt / Stud Bolt	Carbon Steel (SCM435) / Rolled Steel (SS400)

Installation and Operation

Installation Precautions

• Before connecting the product to piping, remove foreign substances and dirt inside the piping to avoid glass damage or opacity.
• Check the direction of the product so that the fluid flowing and the arrow marked on the product are in the same direction.
• Do not apply excessive load, torque, or vibration to the product.

Operation Precautions

• Do not apply a rapid temperature change to the product during initial and usual operations, as it may damage the glass resulting in a blowout of the fluid.
• When used for hot fluid, do not touch the product with bare hands.

TIP

The glasses are consumable parts. Replace the glass if it is eroded by more than 10% of its thickness, if it has scratches or flaws, or if it becomes opaque after contacting certain types of fluid.

Disassembly and Reassembly

DANGER

Completely discharge the pressure inside of the product, piping, and equipment prior to disassembly and inspection. When fluid is hot, cool down the product to the condition that it can be touched with bare hands to avoid scalds.

Disassembly (150L, 150LM):

1. Completely discharge the pressure inside of the product.
2. Remove the bolts and nuts.
3. Take out the covers and glasses. (If the glass sticks to the body and hardly comes off, put the cover on the glass in a way that the outer circumference of the glass fits the inner circumference of the cover, and then tap the cover on its outer side.)

Reassembly:

1. Clean the gasket spaces of the body, covers, and glasses to prevent outside leakage.
2. Attach the gaskets, glasses, and gaskets in this order to the covers and assemble them to the body. (For 150LM, include mica plates between glasses).
3. Tighten covers temporarily with bolts and nuts, then tighten evenly with a torque wrench to prevent glass damage.

Nominal Size	Tightening Torque
65A-125A	29.4 N·m
150A	68.6 N·m

Troubleshooting

Trouble	Cause	Remedy
Fluid flow cannot be observed	1. Foreign substances stick to the inner surface of the glass. 2. The inner surface of the glass has erosion or scratches.	1. Disassemble and clean the product. 2. Disassemble the product and replace the glass.
Outside leakage	1. The gasket leaks. 2. The glass is damaged.	Disassemble the product and replace the gasket or glass as needed.