Yoshitake SF-1S and SF-1F are flap type sight glasses designed for checking flow rate variations of fluids such as cold and hot water, oil, and other non-dangerous fluids. The variation in flow rate can be observed easily using the internal stainless steel flap and scale plates. These compact and lightweight sight glasses can be connected to either horizontal or vertical piping. For steam condensate applications, a model with mica plates (SFM-1S or SFM-1F) is required to protect the hardened glass.

Features

• Variation in flow rate can be checked easily with flap and scale plates.
• Can be connected to horizontal or vertical piping.
• Mica plate is required for steam condensate.

Specifications

Model	SF-1S	SF-1F
Application	Cold and hot water, Oil, Other non-dangerous fluids	Cold and hot water, Oil, Other non-dangerous fluids
Maximum working pressure	1.0 MPa	1.0 MPa
Max. temperature	150°C	150°C
Max. thermal shock	100°C	100°C
Material (Body)	Ductile cast iron	Ductile cast iron
Material (Glass)	Hardened glass	Hardened glass
Material (Flap)	Stainless steel	Stainless steel
Connection	JIS Rc screwed	JIS 10K FF flanged

INFO

• Available with mica plate for steam condensate (SFM-1S, SFM-1F). However, maximum allowable working pressure is 0.6 MPa.
• Glass part is a consumable supply.

Dimensions and Weights

SF-1S (JIS Rc screwed)

Nominal size	d	L (mm)	W (mm)	Weight (kg)
15A	Rc 1/2	80	35	0.7
20A	Rc 3/4	90	35	0.8
25A	Rc 1	115	44	1.4
32A	Rc 1-1/4	127	57	2.5
40A	Rc 1-1/2	140	57	2.8
50A	Rc 2	162	73	5.4

SF-1F (JIS 10K FF flanged)

Nominal size	d (mm)	L (mm)	W (mm)	Weight (kg)
15A	15	130	35	2.2
20A	20	130	35	2.6
25A	25	150	44	4.1
32A	32	160	57	5.9
40A	40	170	57	6.2
50A	50	200	73	9.5

Flow Rate Characteristics (For Water, Horizontal Piping)

• 15A-25A

• 32A-50A

TIP

The flow characteristics shown in the charts above are just for reference and cannot be used for actual measurement.

Installation and Operation

Piping Examples

• For cold and hot water

• For steam condensate

Precaution for Installation

WARNING

1. Before connecting the product to piping, remove foreign substances and dirt inside the piping.
2. When installing, check the direction of the product so that the fluid flowing and the arrow marked on the product are in the same direction.
3. For steam condensate application, make sure to use the product with mica plates to protect the glasses.
4. Do not apply excessive load, torque, or vibration to the product.

Secure the space required for disassembly or replacement of the product at maintenance or inspections:

Nominal size	A (mm)	B (mm)
15A-25A	30 or more	100 or more
32A-40A	35 or more	120 or more
50A	40 or more	150 or more

Precaution for Operation

DANGER

1. Before applying the fluid to the product, confirm that the product is connected to the pipes securely.
2. Do not apply a rapid temperature change to the product during both initial and usual operations. In case of a possible frozen line, take proper measures to remove the fluid inside the piping to avoid freezing.
3. Do not retighten the cover of the product.

Troubleshooting

Trouble	Cause	Remedy
Flap does not move	The flap is caught by foreign substances sticking to the inner surface of the glass, or by scratches.	Disassemble and clean the product to remove foreign substances, or replace the damaged parts.
	Flow rate does not reach the min. limit.	Replace the product with one of a nominal size that ensures a flow rate of the min. limit.
	The product is installed in the opposite direction of the fluid flow.	Reinstall the product correctly (match the arrow mark with the flow direction).
Fluid flow cannot be observed	Foreign substances stick to the inner surface of the glass, or the glass is stained.	Disassemble and clean the product to remove foreign substances.
	The inner surface of the glass has erosion or scratches.	Disassemble the product and replace the glass.
Outside leakage	The gasket leaks, or bolts are loose.	Disassemble the product and replace the gasket, or retighten the bolts to the specified torque.

Disassembly and Reassembly

WARNING

Completely discharge the pressure inside of the product, piping, and equipment prior to disassembly and inspection. When the fluid is hot, cool down the product to the condition that it can be touched with bare hands. Clean the gasket spaces of the body, covers, and glasses. Glasses and gaskets are consumable parts and must be replaced if damaged.

Tightening Torque (for covers):

Nominal size	Tightening torque
15A, 20A	6 N·m
25A	10 N·m
32A, 40A	15 N·m
50A	25 N·m

Note: Attach the scale plates in positions where they can be read from outside of the product. In addition, make the flap point at the minimum scale value. Tighten bolts evenly at the specified torque by using a torque wrench. Overtightening damages the glass.