DN800 Unidirectional Knife Gate Valve

When your large-diameter pipeline requires reliable unidirectional sealing and optimal flow control with superior cutting performance, the DN800 unidirectional knife gate valve delivers exceptional efficiency and operational reliability. This robust DN800 unidirectional knife gate valve is engineered for large-scale applications demanding reliable shutoff in single flow direction — whether you’re managing water treatment facilities, industrial process systems, or pipelines where consistent flow direction and tight sealing are essential. The advanced unidirectional sealing design ensures positive shutoff with optimized flow characteristics, while maintaining the superior cutting action of our proven large-diameter knife gate technology. With focused single-direction performance and heavy-duty construction, it provides dependable service in demanding large-pipeline applications where directional flow control is critical.

Ready to achieve reliable unidirectional control in your DN800 pipeline systems? Contact us today for a DN800 unidirectional solution engineered for your specific flow requirements. Let TOT Valve secure your operations with proven large-valve reliability.

The TOT Valve You Can Depend On – DN800 Unidirectional Excellence When Large-Scale Performance Matters

When your large-diameter process requires reliable sealing in a specific flow direction, optimal flow characteristics, or emergency isolation with maximum efficiency, you need the superior performance of our DN800 unidirectional knife gate valve. With advanced single-direction sealing technology, this large knife gate valve provides reliable shutoff, exceptional flow characteristics, and outstanding durability — all while maintaining the reliable cutting action that makes knife gates ideal for challenging large-pipeline media.

The unidirectional design provides optimized flow control and consistent sealing performance throughout the valve’s service life, making it the preferred choice for large-scale water treatment, industrial process, and infrastructure applications with defined flow direction requirements.

Why DN800 Unidirectional Knife Gate Valve Works for You?

DN800 unidirectional knife gate valve features

Optimized unidirectional sealing provides reliable shutoff with enhanced flow efficiency
Specialized DN800 design with engineering optimized for 800mm large-diameter applications
High flow capacity handles up to 18,000 m³/h with minimal pressure loss
Directional flow optimization maximizes flow coefficient and minimizes turbulence
Streamlined seat configuration ensures superior sealing performance in primary flow direction
Corrosion-resistant construction with stainless steel components for extended service life
Knife-edge gate efficiently cuts through large debris, settled materials, and fibrous media
Multiple actuation compatibility supports manual, pneumatic, electric, and hydraulic operation
Reduced pressure drop design optimized for single-direction flow characteristics
Heavy-duty stem assembly withstands high thrust loads typical in DN800 applications
Emergency isolation capability for rapid pipeline shutoff

DN800 Unidirectional Knife Gate Valve Main Technical Specifications

Large-Diameter Performance, Unidirectional Technology, DN800 Knife Gate Valve

Specification	Details
Valve Size	DN800 (NPS 32″)
Design Standard	MSS SP-81, AWWA C515, EN 593
Pressure Ratings	PN6, PN10, PN16
Maximum Flow Rate	18,000 m³/h at 8.0 m/s velocity

Parameter	PN6	PN10	PN16
Working Pressure	6 Bar	10 Bar	16 Bar
Test Pressure	9 Bar	15 Bar	24 Bar
Max Velocity	2.0 m/s	2.5 m/s	3.0 m/s

Standard	Face-to-Face	Flange Type	Weight Range
MSS SP-81	108mm	ANSI B16.5	580-950 kg
AWWA C515	120mm	AWWA C207	620-1020 kg
EN 593	108mm	EN 1092-2	590-970 kg

DN800 Dimensional Specifications & Materials

Component	Material	Dimension	Standard
Body	WCB/CF8M	Ø800mm bore	ASTM A216
Gate	316L SS	11mm thickness	ASTM A240
Flange	WCB/CF8M	Per rating	ASME B16.5
Stem	316L SS	Ø70-90mm	ASTM A276

Unidirectional Sealing Performance

Flow Direction	Sealing Class	Test Pressure	Leakage Rate
Primary Direction	Class VI	6-16 Bar	≤0.05 ml/min/inch
Tight Shutoff	Class V	6-16 Bar	≤0.1 ml/min/inch
Emergency Seal	Class VI	6-16 Bar	≤0.05 ml/min/inch

Actuation Options for DN800 Service

Manual Operation:

Parameter	Value	Unit	Notes
Gear Ratio	45:1	–	Recommended
Operating Torque	5,500	Nm	At rated pressure
Handwheel Size	650	mm	Standard
Operating Force	950	N	Rim force

Pneumatic Operation:

Parameter	Value	Unit	Notes
Actuator Size	Ø400	mm	Cylinder diameter
Air Pressure	6-7	Bar	Supply requirement
Operating Time	75-150	sec	Variable speed
Air Consumption	180	L/cycle	Per operation

Electric Operation:

Parameter	Value	Unit	Notes
Motor Power	4.0-5.5	kW	Variable speed
Operating Time	210-420	sec	Programmable
Control Accuracy	±0.2	%	Position feedback
Power Consumption	18-28	A	At 380VAC

Hydraulic Operation:

Parameter	Value	Unit	Notes
Cylinder Force	350-550	kN	Output force
System Pressure	140-210	Bar	Operating range
Cycle Time	50-200	sec	Variable control
Flow Requirement	100-180	L/min	Hydraulic flow

Advanced Unidirectional Technology

Flow-Optimized Design: Enhanced flow coefficient with reduced pressure drop

Directional Sealing: Optimized seat geometry for superior primary direction performance

Streamlined Profile: Internal geometry minimizes flow disturbance and cavitation

Debris Management: Large gate opening accommodates substantial debris passage

Thermal Compensation: Design accounts for thermal expansion in large-diameter service

Vibration Resistance: Heavy-duty construction minimizes flow-induced vibration

Application-Specific Configurations

Water Treatment Plants:

Feature	Specification	Benefit	Standard
Seat Material	EPDM	Potable water safe	NSF-61
Body Material	CF8M	Corrosion resistance	ASTM A351
Actuation	Electric	Remote control	IEC 60034
Coating	Fusion Bond Epoxy	Long-term protection	AWWA C550

Industrial Process:

Feature	Specification	Benefit	Standard
Seat Material	Viton/PTFE	Chemical resistance	ASTM D2000
Body Material	Duplex 2205	High strength	ASTM A890
Actuation	Pneumatic	Fast response	ISO 5599
Design	Fire-safe	Emergency safety	API 607

Slurry Applications:

Feature	Specification	Benefit	Standard
Seat Material	Nitrile/Urethane	Abrasion resistance	ASTM D2000
Body Material	A216 WCB	Impact resistance	ASTM A216
Gate Design	Heavy-duty	Extended life	MSS SP-81
Actuation	Hydraulic	High force	ISO 4413

Performance Testing & Validation

Flow Testing:

Test Type	Standard	Parameter	Acceptance
Cv Verification	ISA-75	Flow coefficient	±5% of calculated
Pressure Loss	ISO 5167	ΔP measurement	≤0.35 Bar @ rated flow
Flow Profile	ASME PTC 25	Velocity distribution	Per specification
Cavitation	IEC 60534	Sigma limits	Per application

Sealing Testing:

Test Type	Standard	Pressure	Leakage Limit
Seat Test	MSS SP-81	1.1 × rated	Class VI
Body Test	API 598	1.5 × rated	No visible leakage
Cycling Test	API 598	500 cycles	No degradation

Installation & Engineering Services

Pre-Installation Services:

Site Survey: Pipeline analysis and installation planning
Foundation Design: Structural requirements and anchor bolt layouts
Flow Analysis: CFD modeling for optimal valve positioning and flow optimization
Piping Design: Upstream/downstream piping recommendations

Installation Support:

Rigging Plans: Certified lifting procedures for heavy valve assemblies
Alignment Services: Precision alignment for optimal performance
Flow Direction Verification: Ensuring proper installation orientation
Testing Protocols: Complete commissioning and performance verification
Documentation: As-built drawings and performance certificates

Maintenance & Service Support

Predictive Maintenance:

Component	Monitoring	Frequency	Action
Seat Wear	Torque trending	Monthly	Replace at limit
Stem Condition	Visual inspection	Quarterly	Lubricate/adjust
Gate Edge	Thickness measurement	Semi-annual	Monitor wear
Actuator	Performance data	Continuous	Trend analysis
Body Integrity	NDT inspection	Annual	Report findings

Service Capabilities:

Field Service: On-site maintenance and repair capabilities
Refurbishment: Complete valve restoration to original specifications
Upgrades: Actuator and control system modernization
Training: Comprehensive maintenance training programs

Flow Direction & Installation Guidelines

Proper Flow Direction:

Arrow Marking: Clear flow direction indicators on valve body
Inlet Configuration: Optimized for upstream flow conditions
Outlet Design: Streamlined for downstream flow recovery
Installation Notes: Critical orientation requirements for optimal performance

Installation Best Practices:

Upstream Length: Minimum 5D straight pipe recommended
Downstream Length: Minimum 3D straight pipe for flow recovery
Support Requirements: Adequate pipeline support to prevent valve stress
Access Provision: Sufficient space for maintenance operations

Quality Certifications & Compliance

Manufacturing Standards:

ISO 9001:2015 Quality Management System certification
ISO 14001 Environmental Management System compliance
OHSAS 18001 Occupational Health and Safety certification
PED 2014/68/EU Pressure Equipment Directive compliance

Performance Standards:

MSS SP-81 Knife Gate Valve Standard compliance
AWWA C515 Large Diameter Valve Standard
API 598 Valve Inspection and Testing Standard
EN 12266-1 Industrial Valve Testing Standard

Contact TOT Valve today for technical consultation and competitive quotation on your DN800 unidirectional knife gate valve requirements for large-diameter pipeline applications.