English

English

Get a Quote
Products

Hot Products

Company News

Three Common Causes of Valve Leakage and Emergency Remedies
Three Common Causes of Valve Leakage and Emergency Remedies
2025-05-28

In industrial production, valves are critical components for fluid control, and their sealing performance directly impacts system safety and stability. Leakage not only reduces operational efficiency but may also lead to fluid escape, posing serious safety risks. This article outlines three common causes of valve leakage and provides corresponding emergency response recommendations to help you quickly identify issues, take action, and mitigate risks.   1. Seal Surface Wear or Damage   Cause: During long-term operation, sealing pairs (e.g., valve seat and disc, valve ball and seat) suffer from media erosion, particle abrasion, or corrosion, leading to uneven sealing surfaces and resulting in minor or significant leakage. Emergency Measures: · Minor Leakage: Adjust compression force (e.g., tighten bonnet bolts) to temporarily reduce leakage. · Severe Leakage: Immediately shut down the system to replace or regrind sealing components; replace the entire valve if necessary. Prevention Recommendations: Conduct regular inspections, select valves with appropriate materials and wear-resistant designs. For media containing solid particles, use hard-sealing structures.   2. Packing Aging or Gland Loosening   Cause: Valve stem sealing uses packing materials (e.g., graphite, PTFE), which may age, dry, or crack over prolonged use. Temperature fluctuations can also cause gland loosening, leading to leakage at the packing box.  Emergency Measures: · Tighten packing gland bolts to increase packing compression. · If ineffective, add or replace packing material. · Avoid over-tightening to prevent increased operating torque or stem damage. Prevention Recommendations: Regularly replace packing; select materials compatible with the media and operating temperature. For critical equipment, consider spring-loaded packing glands.   3. Casting Defects or Corrosion Perforation in Valve Body/Bonnet   Cause: Some low-quality valves have casting defects such as sand holes or shrinkage cavities. Prolonged exposure to corrosive media can cause localized perforation of the valve body, resulting in uncontrollable leakage. Emergency Measures: · For small leaks, temporary repairs using metal adhesives or cold welding are possible. · Large-scale damage requires immediate valve replacement. · For high-pressure or toxic/hazardous media, no pressurized repair is allowed; follow shutdown procedures strictly.  Prevention Recommendations: Purchase valves from reputable manufacturers; use corrosion-resistant materials (e.g., 304/316L stainless steel). Perform regular wall thickness inspections on critical pipelines.   Common Questions & Answers (Q&A)   Q1: Can all valve leaks be fixed by replacing packing?A: No. Packing replacement is effective only when leakage is due to packing aging or gland loosening. If the leakage stems from seal surface or valve body damage, other me...

Can Oil Pass Through a Strainer? How Pre-Filtration Works in Lubrication Systems
Can Oil Pass Through a Strainer? How Pre-Filtration Works in Lubrication Systems
2025-05-20

In any efficient and reliable lubrication system, oil cleanliness is a core factor affecting equipment lifespan and operational efficiency. Strainers, as the front-line filtration devices in lubrication systems, play a critical role in pre-filtration. However, engineers and operators often raise the following questions: Can oil pass through strainers smoothly? What exactly is the function of a strainer? How does it differ from subsequent fine filters?   This article systematically explains the role of strainers in lubrication systems, covering their working principles, pre-filtration objectives, and practical applications across different systems.   1. Can Oil Pass Through a Strainer?   Answer: Yes, but with limitations.   (1) Strainer Structure Allows Oil Flow A strainer is fundamentally a low-precision filter made of stainless steel mesh or perforated metal plates. It features uniform pores, typically sized between 80–500 μm (micrometers), allowing most clean oil to flow through unimpeded.   (2) Contaminants Are Blocked Particles such as metal shavings, seal fragments, and carbon deposits in the oil are intercepted by the strainer, preventing them from entering the oil pump or other critical components.   (3) Oil Temperature and Viscosity Affect Flow Efficiency Low temperatures or high-viscosity oil may reduce flow rates or even cause blockages. This is one reason for low oil pressure during system startup.   2. Objectives and Significance of Pre-Filtration   (1) Protecting the Oil Pump Internal pump components (gears, impellers, or plungers) are highly sensitive to solid particles. Pre-filtration prevents particles from entering the pump, avoiding premature wear or seizure.   (2) Reducing Load on Primary Filters By intercepting large contaminants, strainers allow primary filters (e.g., oil filter cartridges) to focus on finer impurities, extending their service life and maintaining stable system flow.   (3) Lowering System Failure Rates Pre-filtration reduces risks such as pump failure, orifice blockages, and lubrication breakdown caused by foreign particles, enhancing overall system reliability.   3. Typical Applications of Pre-Filtration Devices   Application System Strainer Installation Position Strainer Type Internal Combustion Engine Lubrication Oil sump → Pump inlet Coarse metal strainer Hydraulic Systems Tank outlet → Pump suction port Suction strainer or basket strainer Turbine Lubrication Systems Pump inlet Dual-chamber switchable suction strainer Transmission/Clutch Systems Oil sump → Circulation pump inlet Perforated plate + magnetic strainer   4. Design and Usage Considerations for Strainers   (1) Pore Size Selection Must Align with System Precision Requirements 80–100 μm: Typical for engine oil systems. 150–300 μm: Used in hydraulic equipment. >400 μm:  Suitable for low-pressure or open-loop systems.   (2...

Are Ball Valves Suitable for Water Systems? A Practical Guide for Engineers & Installers
Are Ball Valves Suitable for Water Systems? A Practical Guide for Engineers & Installers
2025-04-30

Ball valves, with their simple structure, easy operation, and excellent sealing performance, have become widely used control components in both industrial and residential sectors. Particularly in water supply systems, an increasing number of engineers and installers are choosing ball valves as the primary fluid control device. But are ball valves truly suitable for water systems? How should one properly select and install them to ensure long-term stable operation? This article provides a comprehensive overview from the perspectives of structural principles, performance characteristics, and application recommendations. 1. Advantages of Ball Valves in Water Systems (1) Quick Opening and Closing Ball valves can complete the opening and closing operation with a simple 90° rotation, making them easy to operate and highly responsive—ideal for emergency situations or water systems that require frequent switching.   (2) Excellent Sealing Performance High-quality ball valves are equipped with PTFE or reinforced sealing materials, enabling zero leakage. They are particularly suitable for water supply systems in residential buildings, commercial complexes, and industrial facilities where sealing performance is critical.   (3) Compact Structure and Space-Saving Compared to gate valves or globe valves, ball valves occupy less space and offer flexible installation, making them ideal for water modules with high equipment integration.   (4) Strong Corrosion Resistance Ball valves made of stainless steel, brass, or plastic materials (such as UPVC) offer excellent corrosion resistance, capable of handling various water qualities (soft water, hard water, reclaimed water) and different additives.   2. Application Scenarios Analysis Ball valves are suitable for the following types of water systems: (1) Domestic Water Systems: Such as internal building water supply, point-of-use control for sanitary fixtures, and garden irrigation systems. (2) Industrial Water Systems: Such as cooling water circulation systems, boiler feedwater systems, and water supply for cleaning equipment. (3) Water Treatment Systems: Including reverse osmosis pretreatment, greywater recycling, and wastewater transfer processes. (4) Special Applications: High-pressure hot water systems or cleaning water containing chemical additives.   However, caution should be exercised in the following scenarios: (1) High-Frequency Modulation Conditions Standard ball valves are not suitable for precise flow regulation. It is recommended to use V-port ball valves or control-type electric ball valves. (2) Water Containing Sand, Gravel, or High Levels of Suspended Solids A Y-strainer should be installed to prevent particle blockage or damage to the sealing surfaces. (3) High-Temperature Hot Water Systems High-temperature ball valves with metal sealing structures should be selected to prevent seal aging and deformation.   3. Key Selection Criteria To ensure stable operation o...

4 Inch Gate Valve
加载中...

Cast Steel 600LB 4 Inch Gate Valve Extended Bonnet BW

The gate valve, made according to API 600, is made of CF8, one kind of cast steel. The 4 inch valve is equipped a handwheel, outside yoke, bolted bonnet and extended bonnet. All the accessories are traceable.

  • Payment:

    30% when order confirmed, 70% before shipment
  • Product Origin:

    China
  • Color:

    Customization
  • Shipping Port:

    Shanghai, China
  • Lead Time:

    30~60 days Ex Works after order confirmation
  • Material:

    CF8
  • Method of Operation:

    Handwheel
Inquiry now
Product Detail

Quick Details

Type

Gate Valve

Size

4 Inch

Design Pressure

600LB

Construction 

B.B; OS&Y; Extended Bonnet

Connection Type

Bolt Welded

Operation Type

Handwheel

Body Material

CF8

Disc Material

CF8+STL

Design Code

API 600

Flange Ends

ASME B16.25

Face to Face

ASME B16.10

Inspection and Test

API 598

Temperature

-196~539℃

Medium

Water, Oil and Gas

Origin

China

 

Features

-Full Bore Design

-Superior flow rates & small friction loss

-Low torque value for closing and opening the valve

-Flexible wedge for better seating and easy operation

-Smooth finish and superior sealing for seat face

-Every valve is manufactured with specific number on body for traceability

 

Technical Drawing




Our Service

Dervos customer service is one of our biggest competitive advantages. In Dervos, we provide-

 

1.Quotation within 24 hours or no later than 3 days

This will let you meet the quotation submission deadline and enhance your working efficiency

 

2.Weekly status report of your order

In this way, you will have a clear picture of your order. You do not need to waste time on pushing us for status update

 

3.An 18-month warranty period

A warranty certificate will issued after shipment and you will not have any concern after buying valves.

 

4.Solutions to complaints within 3 days

Quick and responsible actions to complaints will protect your reputation and reduce the financial loss as much as possible.

 


Leave A Message

If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.

Related Products
Extended Bonnet Gate Valve
Extended Stem Cryogenic Gate Valve SW 1 Inch 1500LB

Made of stainless steel, the cryogenic gate valve has extended bonnet, reduced bore, non-rising handwheel, socket weld connection, complying with API 602. Quick Detail Type Gate Valve Size 1'' Design Pressure ANSI 1500 Construction Extended Stem, Bolted Bonnet, Solid Wedge ConnectionType Socket Weld (SW) OperationType Handwheel Operation Body Material A182 F316L TrimMaterial SS316L Design Code ASME B16.34 Face to Face ASME B16.10 End Connection ASME B16.11 Medium Water, Oil and Gas Origin China Available Modifications for Dervos Valves -Design Pressure -Nominal Diameter -Body Material & Trim Material -Material & Type for Packing and Gasket -Valve Operation Type -Modifications of End Connection -Available Extended Stem or Bonnet -Available By-Pass Valve -Customized Coatings & Packaging Related Knowledge Why do we use extended stem for cryogenic valves? The cryogenic valves are mainly used in low temperature liquid media, like liquefied natural gas and petroleum products. The reasons why we use extended stem for cryogenic valves are as below: 1.To maintain the temperature of stem packing in a proper level, since the very low temperature will influnce the sealing function of stem pakcing. 2.To prevent the heat outside from entering the valve and cause energy loss to the application 3.The long stem structure facilitates the quick replacement of the valve's main part through the valve cover. 4.To prevent the parts (like handwheel) over stem from freezing

Plug Valve
1 Inch Class600 Inverted Pressure Balance Lubricated Plug Valve Forged Steel,Full Bore

Quick Detail Type Plug Valve Size 1'' DesignPressure 600LB Construction Lubricated Type, Inverted Type, Pressure Balanced Type, Connection Type FNPT Operation Lever Operation Design Code API6D End Connection ASMEB1.20.1 Pressure & Temp ASME B16.34 Test & Inspection  API 598 Fire Safe API 6FA Body Material A105 Temperature Range ≤80℃ Application Water, Oil, Gas Features --Reliable sealing performance and small torque; --Full bore --Low emission packing; --Fire safe design; --Optional locking device   Technical Drawing Dimension Check Witnessing Tests Packing Why choose Dervos as your partner?   One Stop Service Here in Dervos, we can provide you with one stop service by our complete product list, it means, you don’t need to search for various suppliers for different types of valves, and it will surely save your time and energy. All you need to do is choose Dervos and we will provide complete solutions to you.   On Time Delivery Dervos keeps a high percentage of on time delivery. Why could we achieve that? Our purchasing team follows the order very closely. Plus, our QC and sales person will also do monitoring job on each order.   Strict Quality Control All the members in the QC team are very experienced and professional. For each order, they will check the raw material, manufacturing process, do the pressure testing on shell and seal, and check the valve dimension per assembly drawing. Lastly, they will inspect the painting and packaging.  

JIS Globe Valve Flanged
Marine Bronze Globe Valve DN32 5K FF Flanged

The DN32 JIS 5K globe valve is suitable for marine application. The bronze globe valve is handwheel operated with FF flange. Quick Detail Type Marine Globe Valve Size DN 32 Design Pressure 5K Connection Type FF Flange Design Code JIS F7301 Face to Face JIS B2002 Body Material Bronze Trim Material Bronze Application Water, Oil, Gas Purchasing System Late delivery time become a common issue in 2018. However, Dervos keep more than 90% on-time delivery, so how do we achieve that? It owns our purchasing department.  How do we react to a delay crisis? -Visit the factory everyday and supervise on site -Initiate related resources, such as machining workshops and skilled workers to help on expediting production What benefits could we do for you by keeping on-time delivery? -Avoid penalty from end user -Accumulate reputation -Gain client’s trust FAQ 1. Do you have your own foundry or forge shop?  No, but we have an approved list of foundries over the past decade of casting inspections, which can make sure that our castings are of good quality and all the raw materials are traceable.  2. Can you do NDE Capability radiography, MT, UT, LP? Of course, we can do all these tests upon our clients, but there will be additional charge to these tests. 3. What kind of test will you do for each order? After valve assembly, we will do hydraulic test for shell & sealing and air test. Plus, we will do dimension checking (face to face dimension, flange dimension) as per assembly drawing and standards.

Plug Valve
DN50 PN40 Sleeved Plug Valve RF WCB API599 Lever

DN50 PN40 plug valve is made according to API 599 standard. The valve body is made of A216 WCB. It has the structural characteristics of ferrule type, reduced diameter. Its connection mode is RF. And it has lever operation mode.

Swing Check Valve
4" 600LB Swing Check Valve RF WCB API6D

4" 600LB check valve is made according to API 6D standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of swing type, external pin. Its connection mode is RF.

Butterfly Valve
20" 150LB Lined Butterfly Valve API 609 Lug ASME

20" 150LB butterfly valve is made according to API 609 standard. The valve body is made of WCB. Its connection mode is Lug. And it has turbine operation mode.

DIN Single Plate WAFER Check Valve DN80 PN40
DIN Single Plate WAFER Check Valve DN80 PN40

The single-disc check valve, made of CF8, has excellent resistance to corrosion. Designed in accordance with API594, the valve is of a WAFER type.

Wafer Check Valve
18" 150LB Dual Plate Wafer Lug Type Check Valve API594

18" 150LB wafer check valve is made according to API 594 standard. The valve body is made of A395 Ductile Iron. It has the structural characteristics of double disc. Its connection mode is LUG RF.

DIN DN125 PN16 Stainless Steel Gate Valve HW-OP BB RF
DIN DN125 PN16 Stainless Steel Gate Valve HW-OP BB RF

DN125 PN16 gate valve is made according to DIN 3352 standard. The valve body is made of 1.4408. It has the structural characteristics of bolt cover, rising stem, elastic wedge, with SS316 insulation jacket and structural length of 325mm. Its connection mode is RF EN1092-1 B1. And it has hand wheel operation mode.

Butterfly Valve
WCB DN100 PN40 Three Eccentric Butterfly Valve EN593 Turbine EN1092-1 B

DN100 PN40 butterfly valve is made according to EN 593 standard. The valve body is made of ASTM A216 WCB. It has the structural characteristics of three eccentric, bidirectional one to one pressure test. Its connection mode is EN1092-1 B. And it has turbine operation mode.

DN100 PN10 3-Way Floating Ball Valve Type RF
DN100 PN10 3-Way Floating Ball Valve Type RF

The DN100 3 way ball valve is isolating valve designed to redirect the service fluid flow rather than throttling or regulating purposes. Suitable for water, steam, gas, oil, crude oil, acid, alkali and other liquids and gases without mechanical impurities.

Leave a message

    If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.

Home

Products

about

contact