CEMATIC

Industrial Automation Solutions

HTS Series - Pneumatic Top-Guided Single-Seat Globe Valve

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The industrial control valve is the final control element in a process loop. Its function is to modulate fluid flow in response to a controller signal (typically 4-20 mA or 3-15 PSI), with the aim of maintaining a process variable (pressure, temperature, flow, level) at its setpoint.

The THINKTANK Process Management HTS Series is a straight-through, single-seat, top-guided globe valve, designed for heavy-duty service in high and low-temperature process lines, high differential pressure, and high-precision control requirements.

 

Advantages of HTS Design

-      S-shape flow path: low pressure loss, high flow capacity (Cv up to 797 for DN200)

-      Wide top guide: high vibration resistance, mechanical stability

-      Compact diaphragm or piston actuator with multiple springs: fast and precise response

-      Conforms to IEC 60534 and JIS B2005

-      Inherent rangeability: 50:1 to 75:1

-      Hysteresis: <3% F.S. without positioner, <1% F.S. with positioner

-      Seat leakage: Class IV (metal) or Class V/VI (soft) according to ANSI B16.104

 

2.1 Standard Configuration

Component	Specification
Valve Type	Straight-through globe - S-body
Nominal Sizes	3/4" to 8" (DN20 to DN200)
Nominal Pressure	ANSI Class 125, 150, 300, 600 | JIS 10K-40K | PN1.6 to PN10.0 MPa
End Connections	Flanged: FF, RF, RJ, LG (ANSI B16.5, JIS B2201, JB/T79.1, PN1.6MPa) | Welded: SW, BW | Threaded: Rc
Body Material	WCB, WC6, LCB, CF8, CF8M, CF3, CF3M (see Section 5)
Stem Packing	V-PTFE, PTFE, Flexible graphite
Gaskets	Stainless steel SUS304/316/316L, copper, aluminum
Trim	Single-seat, contoured plug type
Actuator Ambient Temp.	-30 to +70°C
Rangeability	50:1 or 75:1
Hysteresis without positioner	Within +/-3% F.S.
Hysteresis with positioner	Within +/-1% F.S.
Linearity without positioner	Within +/-5% F.S.
Linearity with positioner	Within +/-1% F.S.

 

2.2 Flow Capacity - Nominal Kv / Cv Table

Kv (m3/h with water at dP=1 bar) and Cv (USgal/min with water at dP=1 PSI) values are NOMINAL (100% stroke) for each size and port size. For design purposes, use Cv_valve calculated according to Section 8.

Conversion: Cv = Kv x 1.156 | Kv = Cv x 0.865

 

DN (mm)	Port Size (mm)	Kv EQ%	Cv EQ%	Kv Linear	Cv Linear	Stroke (mm)
DN20	20	6.3	7.3	6.9	8.0	16
DN25	20	6.3	7.3	6.9	8.0	16
DN25	25	10	11.6	11	12.7	16
DN32	20	6.3	7.3	6.9	8.0	16
DN32	25	10	11.6	11	12.7	16
DN32	32	16	18.5	17.6	20.3	25
DN40	25	10	11.6	11	12.7	16
DN40	32	16	18.5	17.6	20.3	25
DN40	40	25	28.9	27.5	31.8	25
DN50	32	16	18.5	17.6	20.3	25
DN50	40	25	28.9	27.5	31.8	25
DN50	50	40	46.2	44	50.9	25
DN65	40	25	28.9	27.5	31.8	25
DN65	50	40	46.2	44	50.9	25
DN65	65	63	72.8	69	79.8	40
DN80	50	40	46.2	44	50.9	25
DN80	65	63	72.8	69	79.8	40
DN80	80	100	115.6	110	127.2	40
DN100	65	63	72.8	69	79.8	40
DN100	80	100	115.6	110	127.2	40
DN100	100	160	185.0	176	203.5	40
DN125	80	100	115.6	110	127.2	40
DN125	100	160	185.0	176	203.5	40
DN125	125	250	289.0	275	317.9	60
DN150	100	160	185.0	176	203.5	40
DN150	125	250	289.0	275	317.9	60
DN150	150	400	462.4	440	508.7	60
DN200	125	250	289.0	275	317.9	60
DN200	150	400	462.4	440	508.7	60
DN200	200	630	728.3	690	797.7	60

Note: For very small flows in DN20 and DN25, select HLS Model.

 

Flow characteristic defines the relationship between the percentage of opening (stem travel) and the percentage of maximum flow passing through the valve, at constant differential pressure. The HTS Series offers two inherent characteristics: Equal Percentage (EQ%) and Linear.

 

3.1 Table R50 - Flow Percentage vs. Travel

Values in green represent the recommended design range (40-80% travel).

 

Travel L (%)	Equal Percentage EQ% (Q/Qmax %)	Linear (Q/Qmax %)
0%	2%	2%
10%	11.8%	3%
20%	21.6%	4.37%
30%	31.4%	6.5%
40%	41.2%	9.6%
50%	51%	14.1%
60%	60.8%	20.9%
70%	70.6%	30.9%
80%	80.4%	45.7%
90%	90.2%	67.6%
100%	100%	100%

 

3.2 Cage Comparison and Selection

The cage is the internal element that defines the valve's flow characteristic. In the HTS Series, the cage is interchangeable, allowing the flow characteristic to be changed in the field without replacing the valve body.

 

Equal-Percentage Cage - V-Port

The equal-percentage cage, identified in the component images, has the following confirmed factory characteristics:

-      Material: CF8 (equivalent to AISI 316, Austenitic Stainless Steel)

-      Port pattern: V-notch / parabolic (V-notch) on the cylindrical wall

-      Nominal Cv: 100 (in the size corresponding to DN80 Port-80)

-      Nominal stroke: 40 mm

-      Leakage standard: Class IV (metal seat) or Class V/VI (soft seat) according to ANSI B16.104

The V-notch creates a flow opening that increases exponentially with stem travel. This geometry ensures that each equal increment of travel produces the same PERCENTAGE increase in flow, which provides high control stability in applications where differential pressure varies with flow rate.

 

Linear Cage - Rectangular Ports

The linear cage uses rectangular or uniform section ports or slots. The flow area increases proportionally and directly with stem travel, producing a linear relationship between opening and flow at constant differential pressure.

 

Characteristic	Equal-Percentage Cage (EQ%)	Linear Cage
Port Pattern	V-notch / parabolic (V-notch)	Rectangular ports / uniform slots
Standard Material	CF8 (AISI 316 equiv.) - Stainless Steel	CF8 or WCB depending on service
Typical Cv available	Cv = 100 in DN80 (Kv=86.5)	Cv = 110 in DN80 (Kv=95)
Inherent Rangeability	50:1 to 75:1	50:1 to 75:1
Flow Behavior	Exponential: Q/Qmax increases exponentially with travel	Proportional: Q/Qmax proportional to travel
Optimal Design Zone	40% - 80% travel (green zone)	40% - 80% travel (green zone)
Ideal Applications	Temperature control, pressure control, variable flow with high control ratio	Level, mixing, applications with constant or nearly constant pressure drop
Behavior at Low Opening	More stable and predictable (smooth curve)	Can be unstable at very low opening
Leakage Standard	Class IV (metal) or Class VI (soft seat) ANSI B16.104	Class IV or Class VI ANSI B16.104

 

When to Specify Each Cage

Specify EQ% (Equal Percentage) Cage when...	Specify Linear Cage when...
-      Process temperature control -      Pressure control with variable pressure drop -      Flow control with high turndown ratio (>10:1) -      Systems where dP decreases as flow increases (centrifugal pumps) -      Applications requiring high sensitivity at low openings -      Chemicals, reactors, heat exchangers	-      Tank level control -      Fluid blending -      Relatively constant pressure drop across the system -      Applications where a direct aperture/flow relationship is desired -      Distribution control in water or gas networks

 

The selection of the valve body material depends on the process fluid, temperature, pressure, and chemical aggressiveness. The HTS Series is available in the following ASTM materials:

 

Code / Material	Standard	Min. Temp.	Max. Temp.	Typical Service
WCB	A216 WCB	-5°C	+425°C	Water, steam, hydrocarbons, general service
WC6	A216 WC6	-5°C	+538°C	High-temperature steam, hot oil
LCB	A352 LCB	-45°C	+350°C	Low-temperature services, LNG
CF8	A351 CF8	-196°C	+538°C	304 stainless steel - acids, treated water, clean chemicals
CF8M	A351 CF8M	-196°C	+538°C	316 stainless steel - chlorides, concentrated acids, pharmaceutical industry
CF3	A351 CF3	-196°C	+538°C	Stainless steel 304L - weld without post-annealing
CF3M	A351 CF3M	-196°C	+538°C	Stainless steel 316L - welding, high corrosion

 

For carbon steel bodies (WCB/WC6/LCB): the trim (plug and seat) is SS 304/316. For stainless steel bodies (CF8/CF8M/CF3/CF3M): the trim is also SS 304/316, with an operating temperature range from -196 to +538°C depending on the plug's surface treatment.

 

The trim comprises the plug + seat assembly. Correct selection determines the leakage class and the operating temperature range:

 

Plug Type	Seal Surface	Leakage Class (ANSI B16.104)	Temperature	Application
Metal (Stainless Steel)	Mirror polished SS	Class IV (<0.01% max Cv)	-196 to +538°C	Steam, gas, high T fluids, severe service
Soft RPTFE	RPTFE coating	Class V/VI (<0.00001% max Cv)	-80 to +200°C	Tight shut-off, water, chemicals, clean fluids
Stellite (ST)	Stellite welding	Class IV/V	-196 to +538°C	Erosive/corrosive fluids, high pressure steam
SS (Polished Stainless Steel)	Stainless Steel SS	Class IV/V/VI	-196 to +538°C	Cryogenic service, ultra-high purity

 

ANSI B16.104 Leakage Criteria

-      Class IV: Leakage <0.01% of max Cv. Polished metallic plug and seat.

-      Class V: Leakage <0.0005 ml/min per inch of seat per PSI. Metal with Stellite treatment.

-      Class VI: Leakage <0.00001% of max Cv. Soft seat (RPTFE or other elastomer). Maximum tight shut-off.

 

The bonnet protects the stem packing and must be selected based on the process fluid temperature:

 

Bonnet Type	Temperature Range	Description / Application
Standard (Plain)	-17 to +230°C	General water service, low/medium pressure steam, hydrocarbons
Extension Type 1	-45 to -17°C and +230 to +566°C	Low temperature and high temperature services. The extension protects the packing from extreme process temperatures
Cryogenic Extension Type 2 (Integral)	-196 to -100°C	LNG, liquid nitrogen and other cryogenics. Integral body welded type
Cryogenic Extension Type 2 (Welded)	-196 to -100°C	Welded alternative for deep cryogenic service (-196 to -100°C)
Bellows Seal	-196 to +566°C	Zero leakage to atmosphere. Ideal for toxic, carcinogenic, radioactive or high-value fluids. Meets emission standards
Steam Jacket	According to process	Maintains fluid temperature. For viscous fluids that solidify, resins, sulfur, asphalt

 

The actuator converts the instrument air signal (4-20 mA via I/P, or direct 3-15 PSI) into linear stem movement. The HTS Series offers three types of actuators:

 

7.1 Actuator Types

-      Single-acting diaphragm actuator (PZMA/PZMB): The most common. Nylon diaphragm with EPDM rubber layers. Integrated return spring. Simple and economical.

-      Single-acting piston actuator: Greater force for large sizes (DN65 to DN200). Return spring.

-      Double-acting piston actuator: No spring. Requires air supply on both sides. Greater force available. Requires safety solenoid (fail-safe).

 

7.2 Fail-Safe Action

Parameter	FO Action (Air to Close)	FC Action (Air to Open)
Code	FO - Fail Open	FC - Fail Close
Mechanism	Direct actuator + spring closes	Reverse actuator + spring opens
Fail position (no air)	Valve OPENS	Valve CLOSES
Typical application	Emergency cooling, pressure relief, fire water injection	Fuel flow control, hazardous chemical dosing
ISA Standard	ISA-5.1: Direct actuator	ISA-5.1: Reverse actuator
Diaphragm spring range	20-100 kPa / 40-200 kPa / 80-240 kPa	20-100 kPa / 40-200 kPa / 80-240 kPa
Piston spring range	125-375 kPa	125-375 kPa

 

The actuator converts the instrumentation air signal (4-20 mA via I/P, or 3-15 PSI direct) into linear stem movement. The HTS Series offers three types of actuators:

 

7.1 Actuator Types

-      Single-acting diaphragm actuator (PZMA/PZMB): The most common. Nylon diaphragm with EPDM rubber layers. Integrated return spring. Simple and economical.

-      Single-acting piston actuator: Greater force for large sizes (DN65 to DN200). Return spring.

-      Double-acting piston actuator: No spring. Requires air supply on both sides. Greater available force. Requires a safety solenoid (fail-safe).

 

7.2 Fail-Safe Action

Parameter	FO Action (Air to Close)	FC Action (Air to Open)
Code	FO - Fail Open	FC - Fail Close
Mechanism	Direct actuator + spring closes	Reverse actuator + spring opens
Fail position (no air)	Valve OPENS	Valve CLOSES
Typical application	Emergency cooling, pressure relief, fire water injection	Fuel flow control, hazardous chemical dosing
ISA Standard	ISA-5.1: Direct actuator	ISA-5.1: Reverse actuator
Diaphragm spring range	20-100 kPa / 40-200 kPa / 80-240 kPa	20-100 kPa / 40-200 kPa / 80-240 kPa
Piston spring range	125-375 kPa	125-375 kPa
Supply Pressure	0.14 / 0.25 / 0.4 / 0.5 MPa	0.14 / 0.25 / 0.4 / 0.5 MPa

 

7.3 Optional Actuator Accessories

-      P/P or I/P Positioner (recommended for control precision)

-      Air filter regulator

-      Side or top handwheel for manual operation

-      Limit switch for position feedback

-      Solenoid valve for fast on/off or additional safety shutdown

-      Position transmitter (motion transmitter) 4-20 mA

-      Booster relay to increase response speed

-      Lock-up valve to retain position on air failure

-      Air lock relay

 

This procedure follows ISA 75.01 methodology for Cv calculation and HTS selection criteria to ensure correct design:

 

Step	Action	Criterion / Formula
1	Define process conditions	Q (m3/h or MMSCFD), P1 (bar), P2 (bar), T (deg C), fluid, density/SG, Pv (vapor pressure)
2	Calculate required Cv or Kv	ISA 75.01 Formula: Cv = Q / (N1 * sqrt(dP/SG)) for liquid. See calculator at cematic.com.mx
3	Apply safety factor	Safe_Cv = Calculated_Cv x 1.20 (minimum 20% margin)
4	Select design opening	Target range: 40% - 80% of travel (60-70% recommended)
5	Calculate valve Cv to order	Valve_Cv = Safe_Cv / design_opening (e.g. Safe_Cv / 0.70)
6	Select DN size	Choose from Table 1 (HTS): Valve_Cv <= EQ% Cv or Linear Cv depending on characteristic
7	Verify actual opening	actual_opening = (Safe_Cv / Valve_Cv) x 100%. Must be between 38% and 82%
8	Select flow characteristic	EQ% for variable pressure/temperature/high rangeability. Linear for level/constant pressure
9	Select body material	CF8/CF8M for chemicals/stainless steel; WCB for general service; LCB for low temperatures
10	Define bonnet type	According to process temperature (see Bonnet Table)
11	Select seat	Metal-ST for steam/high T; RPTFE for tight shutoff; Stellite for erosion
12	Define actuator action	FO if valve must open on failure; FC if valve must close on failure
13	Specify positioner	Recommended whenever required: hysteresis <1% F.S., linearity +-1% F.S.
14	Verify allowable differential pressure	Consult HTS Allowable Differential Pressure Table according to actuator and seat size

 

Support tool: Use the Cv Calculator available at cematic.com.mx to automate steps 2 to 7 with flow characteristic and design point graphs.

 

9.1 Metal Seat - Diaphragm Actuator (HTS Reference)

The maximum allowable differential pressure depends on the seat diameter, the actuator spring range, and whether a positioner is used. Representative examples (PZMA-5 air-to-close actuator, dg=40mm seat):

-      20-100 kPa spring, no positioner: dP max = 0.32 MPa

-      20-100 kPa spring, with positioner: dP max = 0.84 MPa

-      40-200 kPa spring, with positioner: dP max = 1.10 MPa

-      80-240 kPa spring, with positioner: dP max = 2.15 MPa

For exact values, consult the complete HTS datasheet tables (NO. TT2018-01-0802). For high differential pressures in large sizes, a piston actuator is recommended.

 

To quote or order the HTS valve, provide the following information:

-      Nominal size: DN [mm] or NPS [inches]

-      Port: seat size [mm]

-      Nominal pressure: ANSI Class XXX or PN X.X MPa

-      End connection: RF / FF / BW / SW / Rc

-      Body material: WCB / CF8 / CF8M / LCB / etc.

-      Flow characteristic: EQ% or Linear

-      Seat type: Metal (SS) / Soft RPTFE / Stellite

-      Bonnet type: Standard / Extension T1 / Extension T2 / Bellows / Steam jacket

-      Action: FO (air to close) or FC (air to open)

-      Actuator type: Diaphragm / Piston SA / Piston DA

-      Spring range: 20-100 / 40-200 / 80-240 kPa

-      Supply pressure: 0.14 / 0.25 / 0.4 / 0.5 MPa

-      Accessories: Positioner / Handwheel / Limit switch / etc.

-      Fluid, temperature, pressure P1/P2, nominal flow rate (for Cv verification)

 

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