The Yoshitake TSD-42F and TSD-42 are thermodynamic disc steam traps designed for steam condensate applications. Featuring a bimetal ring that solves air-binding problems, these traps ensure a smooth discharge of cold condensate or air at the start of operation, enabling steam equipment to efficiently start running. The main parts are constructed from stainless steel (SCS2A body and SUS420J2 disc/seat with special heat treatment), providing excellent corrosion resistance.

Capable of operating under temperatures up to 425°C and pressures up to 4.2 MPa, the TSD-42 series is suitable for various industries, including heavy, light, and general industrial applications. The traps feature an insulation cover to avoid frequent on-off operation and a built-in strainer, eliminating the need for an external strainer before the trap. Plumbing is easy to perform as they can be installed vertically or horizontally as desired.

Specifications

Model	TSD-42	TSD-42F
Nominal Size	10A - 25A	15A - 25A
Application	Steam condensate	Steam condensate
Working Pressure	0.035 - 4.2 MPa	0.035 - 4.2 MPa (varies by flange rating)
Allowable Back Pressure	50% or less of inlet pressure	50% or less of inlet pressure
Maximum Temperature	425°C	425°C (varies by flange rating)
Body Material	Stainless steel (SCS2A)	Stainless steel (SCS2A)
Disc, Seat Material	Stainless steel (special heat treatment)	Stainless steel (special heat treatment)
Connection	JIS Rc, NPT, BSPT screwed	JIS 10K/20K/30K/40K RF, PN 25/40, ASME 150/300/600lb

INFO

Relationship between the maximum pressure and the maximum temperature is according to the applicable flange standard pressure-temperature rating (JIS B2220, BS EN 1092-1, ASME B16.5).

Dimensions and Weights

TSD-42 (Screwed)

Nominal size	L (mm)	H (mm)	H1 (mm)	A (mm)	Weight (kg)
10A	78	76	23	32	0.65
15A	78	76	23	32	0.6
20A	85	79	24	38	0.7
25A	95	86	27.5	45	0.9

TSD-42F (Flanged)

JIS 10K / 20K RF

Nominal size	d (mm)	L (mm)	H (mm)	H1 (mm)	Weight (kg)
15A	15	127	76	23	2.0
20A	20	131	79	24	2.4
25A	25	131	86	27.5	3.5

JIS 30K RF

Nominal size	d (mm)	L (mm)	H (mm)	H1 (mm)	Weight (kg)
15A	15	135	76	23	3.4
20A	20	135	79	24	3.6
25A	25	139	86	27.5	4.6

JIS 40K RF

Nominal size	d (mm)	L (mm)	H (mm)	H1 (mm)	Weight (kg)
15A	15	139	76	23	3.6
20A	20	139	79	24	4.0
25A	25	144	86	27.5	5.0

Maximum Continuous Discharge Capacity

To select the product size, secure a safety factor of 4 to 5. For example, if you need a steam trap with a capacity of 100 kg/h, a trap with a capacity of 400 to 500 kg/h should be selected for maximum efficiency.

The back pressure (outlet pressure) should be considered when selecting discharge capacity, as it depends on the operating differential pressure (the difference between the inlet and outlet pressure).

Operation

Phase	Description	Diagram
1. Start-up	At start-up, the bi-metal is cooled in a shrunk and closed condition, keeping the disc lifted up. Incoming air and condensate are discharged smoothly without air-induced troubles.
2. Closing	When hot condensate flows in, the bi-metal expands, slipping down the slant of the valve seat. Flash steam moving at high velocity under the disc creates a low-pressure area, forcing the disc down until it seats.
3. Inflow	Condensate flowing into the trap reduces temperature, causing the steam inside the control chamber to condense. This pressure drop decreases the downward force on the disc.
4. Opening	When the downward force becomes lower than the upward force from the jetting-out port, the disc is lifted to the opened position and condensate is discharged.

Installation and Piping

The trap can be installed vertically or horizontally.

WARNING

To discharge condensate to the atmosphere, lead the outlet to a place where there is no possibility of physical damage. Failure to follow this notice may result in injury and scalds when condensate blows out.

Piping Examples

Description	Correct
If installed close to a regulating valve, place the product at the inlet side.
To discharge condensate from the steam main, install so condensate discharges from the bottom (drain-pot).
The product should be installed below a device which causes condensate.
To discharge condensate from more than one device, install a trap for each device independently.
The diameter of the collecting pipe should be more than the summation of sectional areas of discharge pipes. Install check valves.
To recover condensate, connect discharge pipes at the top of the collecting pipe.
End portion of discharge pipe should be off the water surface in the pit.

Maintenance and Troubleshooting

WARNING

Completely discharge internal pressure of the product, piping, and equipment, and cool down the product prior to disassembly or maintenance.

Troubleshooting

Trouble	Cause	Remedy
Condensate is not discharged	1. Blockage in valve seat discharge hole. 2. Strainer is clogging. 3. Breakage from abnormal pressure (freezing/water hammer). 4. Steam locking.	1. Disassemble and clean. 2. Disassemble and clean. 3. Replace product. 4. Change piping layout.
Continuous blowout	1. Foreign substances on disc/seat. 2. Abrasion/scratches on disc/seat. 3. Back pressure exceeds max allowable. 4. Applied pressure is less than minimum.	1. Disassemble and clean. 2. Replace product. 3. Keep back pressure within limits. 4. Replace with appropriate model.
Steam leakage	1. Loosen joint between body and cap. 2. Loosen joint between body and strainer cap. 3. Breakage from abnormal pressure.	1. Retighten cap. 2. Replace gasket and retighten strainer cap. 3. Replace product.
No-load operation	1. Abrasion/scratches on disc/seat. 2. Foreign substances on disc/seat.	1. Replace product. 2. Disassemble and clean.

Disassembly and Reassembly

1. Disassembly of body [1] and cap [2]: Loosen and remove the cap [2] (nominal size: 38 mm) with a wrench.
2. Disassembly of strainer [6]: Loosen and remove the strainer cap [8] (nominal size: 21 mm) with a wrench, and then take out the strainer [6].
3. Reassembly: Reassemble in the reverse order. Check the side of the disc [3]; if attached wrongly, steam or condensate is continuously discharged. Replace the consumable gasket [7]. Apply anti-seizure agent to the screw parts. Tighten the cap [2] to 90 N·m and the strainer cap [8] to 80 N·m.