Tools & Hardware

Disc Springs for Valves, also be known as Belleville Springs for Valves, Belleville Washers for Valves ... Disc springs are widely used in various types of valves such as Ball Valves, Regulating Valves, Globe Valves, Pigging Valves, and Sea Valves. The load of Disc Springs is large with small deflection, they can provide sufficient valve seat sealing force. The role of the Disc Spring inside the valve is to maintain sufficient contact pressure on the joint. Using Hegong Disc Springs Stacks either in series or parallel, obtain the required force and stroke, to meet the needs of each valve. Disc Springs Stacks apply a pressure and absorb the contraction and expansion that may occur due to pressure, temperature, or relaxation. Depending on the working environment, Belleville Springs for Valves can be produced by material such as Inconel750, Inconel718, 17-7PH. These materials have good corrosion resistance and high temperature resistance, can also provide adaptable working loads under harsh conditions and high temperature environments. Disc springs are the key part to fix Ball Valve, its performance will directly affect the sealing effect of the valve. When we design and manufacture Disc Springs for Ball Valves, we should pay attention to the following points.

Disc Springs for Ball Bearing, also be known as “Bearing Preload Disc Springs”, they are assembled with the radial ball bearings, act as a compensator of thermal expansions during their working. Using Disc Springs to preload radial ball bearings, helps to maintain positioning accuracy, eliminate shaft end play, and minimize vibration and shaft deflection by distributing the load evenly around the bearing race, extends the bearing life, eliminate excessive running noise. In most cases, the outer race of the ball bearing is preloaded with the Disc Spring, and in some cases it is desirable to preload the inner race of ball bearing.  The recommended load value is achieved when the disc spring is deflected to 75% of the initial cone heights (ho). The proper designed ho/t ratio makes a load of disc spring remains nearly constant for a large deflection range.  Disc springs for valves are designed to operate within 20%-80% of their total deflection. Misuse can result in overload, bigger error, or premature fatigue failure. If your working environment requires disc springs to work outside this range, HEGONG SPRING ® engineers can provide guidance or recommend other solutions. Be free to contact with our engineers Tech@DiscSpringsMFG.com.

Cryogenic Disc Springs made of Cryogenic(high temperature) resistant material as Inconel 718 , 750 , Nimonic 90 , these disc springs are applied for high temperature&cryogenic(from -50°C up to +500°C) environment and ultra-high temperature&cryogenic(from -250°C up to +700°C) environment. Cryogenic Disc Springs(High Temperature Disc Springs) are widely used in Valves, Heat Exchangers, Boilers, Industrial Furnaces & Ovens, Cryogenic Technology, Special Chemical circumstances, etc. HEGONG Cryogenic Disc Springs are designed & manufactured according to DIN2092 & DIN2093, GB/T 1972-2005, and ISO 19690. The engineers of HEGONG SPRING ® are pleased to design the springs for the specific applications together with the customer’s R&D department. Be free to contact with our engineers Material: The common material for wholesale Cryogenic Disc Springs include: 30W4CrVA, H13, X22CrMoV12-1, CuBe2, Inconel 718, Inconel 750, Nimonic 90.

High Temperature Disc Springs High Temperature Disc Springs made of high temperature(Cryogenic) resistant material as Inconel 718 , 750 , Nimonic 90 , these disc springs are applied for high temperature&cryogenic(from -50°C up to +500°C) environment and ultra- high temperature&cryogenic(from -250°C up to +700°C) environment. High Temperature Disc Springs (Cryogenic Disc Springs) are widely used in Valves, Heat Exchangers, Boilers, Industrial Furnaces & Ovens, Cryogenic Technology, Special Chemical circumstances, etc. Hegong High Temperature Disc Springs are designed & manufactured according to DIN2092 & DIN2093, GB/T 1972-2005, and ISO 19690. The engineers of HEGONG SPRING ® are pleased to design the springs for the specific applications together with the customer’s R&D department. Be free to contact with our engineers.

Corrosion Resistant Disc Springs, made of stainless steel, such as SUS301, SUS302, SUS316, 17-4PH, 17-7PH, 15-7Mo, their resistant to corrosion is higher than general Disc Springs made of spring steel, so they also be known as "Stainless Steel Disc Springs". Stainless Steel Disc Springs are also widely used in National Defense, Metallurgy, Petrochemical, Wind Power, Engineering, Food Processing Equipment, etc.  In addition to Stainless Steel Disc Springs , High Temperature Disc Springs, Cryogenic Disc Springs are suitable for high temperature or Cryogenic applications, you can choose according to the application requirement. Corrosion Resistant Disc springs manufacturer are designed & manufactured according to DIN2092 & DIN2093, GB/T 1972-2005, and ISO 19690. The engineers of HEGONG SPRING ® are pleased to design the springs for the specific applications together with the customer’s R&D department. Be free to contact with our engineers.

Disc spring can be used in a single piece, as well in multi pieces with different combinations. disc springs stack set is usual to use disc spring stacks with various combinations to meet your specified applications. Description The required various load/deflection characteristics of Belleville disc springs China can be obtained from the various stacking combinations. The stack combination methods and load&deflection relation as the table below. The designed & expected load/deflection characteristics of disc springs stack just be reached under the correct installation. A guiding element is necessary to keep the Hegong disc springs stack in position. This should preferably be a mandrel. HEGONG SPRING® can deliver disc springs stack pre- assembled on a guiding element and highly recommend this way. Advantages of wholesale disc springs stack: 1. Provide specific load/deflection data for the whole set of disc springs stack. (HEGONG SPRING®’s load testing machines can measure loads up to 4000KN) 2. Small load tolerance 3. Easier to install

Belleville Disc Springs also was called "Disc Springs" "Conical Disc Springs", include disc spring stacks, Corrosion Resistant Disc Springs, High Temperature / Cryogenic Disc Springs, Disc Springs for Ball Bearing, Disc Springs for Valves. Disc Springs are widely used in petrochemical, electric power, metallurgy, engineering, machine tools, national defense, and other industries. Bearing Preload Disc Springs manufacturer Description The Disc Spring concept was first invented by a Frenchman Louis Belleville in 1865. So, disc spring is commonly known as Belleville Springs. And sometimes it also was called "Conical disc springs" "Belleville Disc Springs" or "Belleville Washers". Hegong Disc Springs are conically washers and have a rectangular cross- section, which is loaded in the axial direction. It has a small volume and large energy storage compared to traditional helical springs and can be used as a single disc spring or in the stack (stack in parallel, in series or parallel & series combination). The standards for disc springs mainly include DIN2092 (Calculation) / DIN2093 ( Quality Specifications-Dimensions ) of Germany, JIS B 2706- Japan, GB/T 1972-2005 of China and ISO 19690 : 2017 ( HEGONG SPRING ® is the drafting team member for international standard ISO 19690 : 2017 and Chinese national standard GB/T 1972-2005 ). Among them, DIN2093 is most widely used in the world. belleville washer design are designed & manufactured according to DIN2092 & DIN2093, working for dynamic or static applications. The engineers of HEGONG SPRING® are pleased to design the springs for the specific applications together with the customer’s R&D department. Be free to contact with our engineers. Tech@DiscSpringsMFG.com. Genera , lly, disc springs include disc spring stacks, Corrosion Resistant Disc Springs, High Temperature / Cryogenic Disc Springs, Disc Springs for Ball Bearing, Disc Springs for Valves. Surface Condition And Corrosion Protection: Polish Phosphating and oil Mechanical Zinc Plating Chemical Nickel Plating Docromet / Geomet Coating Electrophoresis Tolerance: The Tolerance is according to DIN2093 standards Belleville Spring Washers exporter Specification: The following specification table covers the "standard" sizes and some non- standard sizes. HEGONG SPRING ® customizes Belleville Disc Springs as well. The max OD is up to 1000mm. If you require the custom Belleville Disc Springs, please contact our sales engineers.

CONTACT US +8613131745018 valvehr@jhyvalve.com 86 , -317-8030-499 Contact Now Product Description Ductile Iron Flange Type DI Gate Valve Product Description: DI Gate Valves are designed and manufactured to meet the highest standards of quality and performance, and are available in a wide range of pressure classes, structure types, and temperature ranges. DI Gate Valves are suitable for a variety of applications, including high pressure, low pressure, medium pressure, and normal temperature systems. These valves are available in PN10, PN16 pressure classes, flange type structure, and manual power. DI Gate Valves are manufactured to BS, DIN, GOST, ANSI, and JIS standards, and feature GGG50 gate valve technology. DI Gate Valves are renowned for their durability, reliability, and safety. Technical Parameters: Parameter Details Power Manual Application Potable Water Supply;Industrial Fields,For Fire Pipes Color Red, Blue ,customizable Size DN50-DN600, DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350, DN400 Standard BS,DIN,GOST.ANSI,JIS Structure Flange Type Pressure Class PN10,PN16 End Connection Flanged Material Ductile Iron Temperature of Media High Temperature, Low Temperature, Medium Temperature, Normal TemperatureDN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 0DN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 1DN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 2 Applications: JHY is proud to present its latest BS gate valve, the DN100. It is a ductile iron gate valve, made with a flanged end connection. It is ideal for potable water supply and industrial fields, as well as fire pipes. The DN100 is designed to handle high, low, medium and normal temperature. It is powered manually, for maximum convenience. The DN100 is the perfect solution for any situation requiring a robust and reliable gate valve. JHY stands by its quality and is sure that the DN100 will provide excellent services for many years to come. It is an excellent choice for any industrial application. Support and Services: DI Gate Valve provides technical support and services to ensure its products are running at their optimal performance. Our team of experts is available to answer any questions and provide timely solutions. Our technical support team is available 24/7 and can provide assistance with installation, troubleshooting, and maintenance. Furthermore, we offer a range of preventive maintenance services, including routine inspections, adjustments, and repairs. Our services also include product upgrades and customized solutions to meet customers’ specific needs. DN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 3DN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 4 Packing and Shipping: DI Gate Valves are packaged and shipped in a standard box. The box should include the following items: DI Gate Valve Installation instructions Safety and operation instructions Product warranty information The box should be securely sealed and clearly labeled with the product name and shipping address. It should also include a tracking number for tracking the shipment. DN250 DN350 DI Gate Valve Ductile Iron PN16 Gate Valve Flange Type 5

Consuelo is from a hydraulic equipment manufacturing company in Spain, and has been engaged in procurement for less than 3 years. At the beginning of last year, their excavator was complained. After checking, it was judged that the hydraulic cartridge counterbalance valve was leaking, and the valve spool was worn. According to the feedback from the original hydraulic cartridge counterbalance valve manufacturer, the valve spool is made of 12L14 free- cutting steel, which is commonly used in the industry. The only solution is to replace the hydraulic cartridge counterbalance valve with new ones, which means that the valves will need to be replaced every 8 months. Consuelo knew that his boss and customer would not be satisfied. He tried to find a new manufacturer of hydraulic cartridge counterbalance valve, but failed. Consuelo found AAK on Google, and noticed that AAK had introduced some customer cases about the difficult and complicated problems of the hydraulic cartridge counterbalance valve, and sent an email asking: Can AAK hydraulic cartridge counterbalance valve achieve no internal leakage and be durable for more than 1 year? After communication, we learned that the hydraulic cartridge counterbalance valve produced by the original cartridge valve manufacturer had internal leakage after being used for about 8 months. According to the schematic diagram of the hydraulic system provided by Consuelo, combined with the working conditions of the excavator, AAK engineers found that it was not only the problem of changing the material of the valve spool, but also the problem of optimizing the structure of the original hydraulic cartridge counterbalance valve. After 40 days, AAK sent 6 samples of hydraulic cartridge counterbalance valve. Last week, Consuelo said that he would purchase 120 hydraulic cartridge counterbalance valves to replace the ones currently used on the excavators. The excavators installed with AAK hydraulic cartridge counterbalance valve have been used for 10 months, and there is no complaint of leakage. AAK improved the original hydraulic cartridge counterbalance valve from the 3 aspects: 1. Change in material selection. AAK hydraulic cartridge counterbalance valve spool is made of 20CrNi2MoV high carburized bearing steel, which is more suitable. We never consider the general standard of the industry, but what material is most suitable for the working condition. 2. The change of the seal, the inner cone of the check valve spool and the lower end face of the valve seat form a line seal, the outer cone of the control valve spool and the through hole on the valve seat form a line seal, and the lower through hole section of the relief valve spool and the valve seat form a line seal. Three lines are sealed to ensure no leakage. 3. With the change of valve operation, the overflow valve spool slides to control the on-off of the oil outlet and the oil return port, with the help of the coordination of the control valve spool and the valve seat. Whether the load rises or falls, the check valve spool is opened and closed from twice to once, and the valve spool life is doubled. AAK hydraulic cartridge counterbalance valve, has no internal leakage and is durable. You can also try it! https://www.aakindustry.com/info-detail , /cartridge-counterbalance-valves-aak505

4 hydraulic valve manufacturers, made samples for 5 samples, but none of them were able to produce the hydraulic cartridge check valve with a length diameter ratio of 25:1 successfully. AAK adopted a special slender shaft processing technology, and the sample passed the testing successfully at one time, the parameters of the hydraulic cartridge check valve were up to standard, and the surface roughness was improved by 0.3%, and the geometric accuracy was improved by 0.8%. German customer was satisfied. Cheney is a senior buyer of hydraulic cartridge valves in Germany. He is good at dealing with different abnormal conditions of hydraulic valves, such as stuck valves, leaks, cavitation etc. But this time, he was trapped by a hydraulic cartridge check valve with the ratio of shaft length to diameter greater than 25. Four hydraulic cartridge valve manufacturers, made samples for 5 times, spent 10 weeks, but without any results. Compared with conventional valves, this slender shaft hydraulic cartridge check valve has poor rigidity, easy deformation, large vibration, difficult cutting control, and strict requirements for processing technology. This is the root cause of the failure of most hydraulic cartridge check valve manufacturers. Cheney sourced for nearly 1 week, but still no hydraulic valve manufacturer is willing to take over. When he was browsing B2B, he saw AAK and noticed that AAK had an article about the hydraulic valve with long length diameter ratio, so he left us a message. After several rounds of email communication, Cheney seemed to see the hope and sent the drawing of the hydraulic cartridge check valve to us. 2 weeks later, AAK sent 8 samples of slender shaft hydraulic cartridge check valve. 7 days later, Cheney emailed that the parameters of AAK slender shaft hydraulic cartridge check valve were up to standard, its functions were normal, its surface roughness was improved by 0.3%, and its geometric accuracy was improved by 0.8%, which surprised their engineers. The reason why AAK succeeded in the first time is due to following 3 points: 1. Selection of drill bit and fixture: match the appropriate long drill bit from 3 aspects of hardness, heat resistance and impact toughness, and adopt the clamping method of one clamp and one top, at the same time use flexible movable center to compensate thermal deformation elongation, so that the slender shaft can stretch freely after being heated to avoid thermal deformation. 2. Control of cutting amount and cutting fluid: reasonably select the drilling amount according to the length diameter ratio. During cutting, the cutting fluid shall be fully poured to inhibit the rise of working temperature, thus inhibiting the thermal deformation. 3. Sharp tool control: the tool change frequency is increased by 3 times. Effectively reduce the friction and heat between the trolley knife and the workpiece, and control the thermal deformation from the source. In recent years, AAK has successively supplied a Spanish customer with hydraulic cartridge check valves with the same length diameter ratio, and it is repeatedly ordered 4 times a year. Although it is difficult to machine the hydraulic cartridge check valve with long length diameter ratio, AAK has unique skills. The slender shaft hydraulic cartridge check valve of AAK, is purchased by a Spanish customer 4 times a year. Welcome to have a small try! https://www.aakindustry.com/info-detai , l/hydraulic-cartridge-check-valves-aak358

A few days ago, I received samples of hydraulic directional control valves produced by other manufacturer from my old customer Ahmik. Ahmik is from Israel and started purchasing hydraulic directional control valves from AAK 2 years ago. In August of the previous year, they developed a high-pressure hydraulic manifold and needed to purchase a hydraulic directional control valve. Ahmik purchased the hydraulic directional control valve from a manufacturer that has been cooperating for 3 years. After 6 months, there was leakage in the valve, especially severe wear and tear. The original hydraulic valve manufacturer stated that the high-pressure hydraulic directional control valve can only hold a service life of 6 months at present. Ahmik didn't quite believe it, so he sent me a sample to see if it could achieve a service life of over 1 year. We disassembled the original manufacturer's hydraulic directional control valve sample and frankly, the manufacturing quality is not poor. Why not wear resistant? Based on the hydraulic schematic and operating instructions provided by Ahmik, we understand that the problem lies in the material selection of the valve body. The original manufacturer used 45 Cr material to produce valve bodies, which is not a big mistake, because this is a commonly used material for valve bodies. AAK never follows industry trend in material selection and strictly selects materials according to the working conditions. If the service life of this hydraulic directional control valve needs to be over 1 year without any damage, while ensuring machining accuracy, efforts need to be made on the material of the hydraulic directional control valve, especially the wear resistance of the valve body. I recommended Ahmik to use 3Cr3Mo3W2V hot working die steel to produce the valve body of this hydraulic directional control valve. If the original manufacturer was unwilling to use this material or if the processing is difficult, AAK can complete it. 3 days later, Ahmik asked me to copy the original hydraulic directional control valve sample, because the original hydraulic valve manufacturer is not confident in achieving a service life of more than 1 year. Indeed, the processing difficulty of 3Cr3Mo3W2V hot work mold steel is higher than that of 45 Cr, and the accuracy error is large. However, AAK has already had multiple factual cases of processing this material. The hardness and wear resistance of 3Cr3Mo3W2V hot working die steel are the preferred choice for producing high-pressure hydraulic valve bodies, but most hydraulic valve manufacturers in China choose 45 Cr. This material also has one characteristic, the entire cross-section and mechanical properties of the material are very consistent, ensuring that the valve body is more resistant to impact and corrosion during the system operation process, and is safe for 1 year. AAK hydraulic directional control valve, under high pressure, is still safe for 1 year, you can also give it a try! AAK HYDRAULIC VALVES (590) 2023-05-23 https://www.aakindustry.com/info , -detail/directional-control-valves-aak590

At the beginning of last year, Leander contacted me under the introduction of one of our old customers in Greece. I learned that their company sold a batch of large excavators to South America. During operation, the pressure supply is often insufficient. They know that there is a problem with the hydraulic cartridge pressure control valves, especially the valve body is obviously worn. The original manufacturer of the hydraulic cartridge pressure control valve was evasive and regarded that the wear was caused by the high-frequency and high- pressure work of the excavator, because the valve body was made of 11L44 steel, which was the industry standard. Leander was helpless and his boss was angry. The boss asked him to find the manufacturer of the hydraulic cartridge pressure control valves with durability of more than 2 million times. Leander wasted more than a week but without any gain. According to the drawings and working condition parameters of the hydraulic cartridge pressure control valve provided by Leander, the material selection is the key if the service life of this hydraulic cartridge pressure control valve is more than 2 million times. The next day, I replied to Leander that AAK was 95% confident, I couldn't say 100%. Leander sent the trial order later. 35 days later, the trial order of the 50 pcs of hydraulic cartridge pressure control valves were sent. More than 1 month later, Leander informed by email that AAK hydraulic cartridge pressure control valves had been installed on the excavator. Their engineer specially tested the performance, which can be achieved 2 million times. I told him that AAK manufacturing quality benchmarked HydraForce, and the performance of 2 million times is not a slogan, but a fact. Leander is relaxed and no longer worried about customer complaints. For the hydraulic cartridge pressure control valve with more than 2 million times, AAK separated the peers from 3 aspects: 1. The valve body of this hydraulic cartridge pressure control valve is made of Japanese SCM415 steel, and its mechanical property is more than 70% stronger than 11L44 steel. After carburizing and heat treatment, its hardness is more than HRC66, and its wear resistance is more than 3 times higher, ensuring wear resistance of more than 2 million times. 2.The machining of SCM415 material, is proceeded with special diamond reamer, equipped with American precision honing machine, the precision of valve hole after finishing can be controlled below 0.8μm, the possibility of leakage is eliminated. 3.100% inspection, AAK independently developed durability testing equipment, implemented NFPA/T2.6.1 standard, and each hydraulic cartridge pressure control valve was inspected. Most hydraulic cartridge valve manufacturers conduct spot checks and do not have good testing equipment. Leander told me privately that his boss thinks highly of him more and more, and has suggested him take AAK as their preferred supplier of hydraulic cartridge pressure control valves. AAK hydraulic cartridge pressure control valve, with the performance of more than 2 million times, you can also have a small try! https://www.aakindustry.com/info-detai , l/hydraulic-cartridge-pressure-control- valves- , 357

Erasmus is from a hydraulic equipment company in Colombia. He has been purchasing smoothly, but a batch of hydraulic cartridge directional control valves stumped him. The loader sold by their company less than 1 year has been complained of shaking. During after-sales service, it is found on the site that the valve spool of the hydraulic cartridge directional control valve is stuck during operation, which is caused by the deviation of the valve hole accuracy. The original manufacturer advised that there should be not many pieces of hydraulic cartridge directional control valve was stuck and could be replaced, but there were more and more complaints later. The boss was not satisfied with Erasmus's purchase this time, asked him to replace the manufacturer of the hydraulic directional control cartridge valve, and requested that the service life of the valve be more than 18 months. Erasmus contacted more than 10 cartridge valve manufacturers. They either disliked the small quantity or needed 60 days of production. Erasmus became very anxious. Erasmus found AAK hydraulic valve in B2B and left a message to us: Can you produce the hydraulic cartridge directional control valve in 40 days with a service life of 18 months? I guess he encountered problem when he purchased the hydraulic cartridge directional control valves. After communication, I learned his dilemma in purchasing. According to the drawing of hydraulic cartridge directional control valve provided by Erasmus, this is not difficult, but the key is performance. 2 days later, we received the PO for the hydraulic cartridge directional control valve. Erasmus said that although the price of AAK hydraulic cartridge directional control valve was 20% higher than that of the original cartridge valve manufacturer, he still chose AAK because he valued the 18 months of service life. After 40 days, AAK sent 40 samples of hydraulic cartridge directional control valves. Last week, Erasmus informed by email that the AAK hydraulic cartridge directional control valve had been installed on the equipment for 1 year, and there was no customer complaint. Most surprising to his engineers, AAK valve hole accuracy reached 0.3μm, but the original directional control valve manufacturer is above 0.7μm. I told him, if no accident, there will be no worries for 18 months. AAK constantly improves the performance of the hydraulic directional control cartridge valve from 3 aspects. Although the price is 20% higher than that of peers, the service life is twice that of peers. 1. In processing, this hydraulic cartridge directional control valve uses OKK ultra precision machine tool of Japan, and its nano level numerical control system ensures that the processing accuracy can reach 0.01~0.3 μm. The precision of shape and contour is 0.003 ～ 0.1μm. 2. In terms of detection, the German small micropore diameter tester is used to detect the valve hole of each hydraulic directional control cartridge valve. 100% full inspection, and the measurement accuracy is within 0.1μm. 3. In terms of assembly, most of hydraulic directional control valve manufacturers adopt the selective assembly method. AAK uses the unified assembly method, and the assembly efficiency is twice that of peers. Not only fast, but also stable. Although the price of AAK hydraulic directional control cartridge valve is 20% higher than that of its peers, its service life is twice that of its peers. You can also try a small order! https://www.aakindustry.com/info-det , ail/directional-control-valve-aak433

Esperanza is from Spain and has over 1 year of procurement experience from hydraulic cartridge valve manufacturers in China, which has been relatively smooth. At the beginning of this year, Esperanza encountered difficulties in purchasing the CV08-20 hydraulic check valve. She purchased 120 pcs of CV08- 20 hydraulic check valves from an old supplier. After 4 months, 4pcs of the hydraulic check valves were found to have leaks, a less than 2% of leakage. The manufacturer of CV08-20 hydraulic check valves advised that he cannot guarantee that each hydraulic check valve has no leakage, but is willing to offer 4 pcs for free replacement. Esperanza's biggest concern is that the quality of this manufacturer is unstable, and they have to find another hydraulic cartridge valve manufacturer in China. Esperanza left a message on AAK website: Does AAK have CV08-20 hydraulic check valve? Can AAK guarantee that the first order of all 120 pcs of hydraulic one-way valves be leak free? I asked if she had encountered any leakage problem on the CV08-20 hydraulic check valve. After communication, we learned that the original hydraulic cartridge valve manufacturer cannot guarantee that each hydraulic check valve has no leakage. Although the CV08-20 hydraulic check valve is relatively conventional, for manufacturers, the competition lies in the stability of manufacturing quality and the details of subsequent quality inspection. As long as these 2 steps are strictly controlled, it is not difficult for all 120 pcs of hydraulic check valves to have no leakage. After 3 rounds of communication, the PO was confirmed. We shipped the goods at the end of March. Yesterday, Esperanza sent us an email. The CV08-20 hydraulic check valves shipped by AAK have been used for 6 months and no leakage has been found. They need to order another 260 pcs of CV08-20 hydraulic check valves and need the soonest delivery date. I told him that the service life of AAK valve is at least twice that of its original manufacturer. After production, each valve needs to be tested for pressure holding and leakage. The AAK inspection personnel first insert the hydraulic check valve body into the rubber tube of the manual pressure maintaining tester, then pinch the pressure punching airbag, wait until the pressure gauge pointer is at the standard pressure value position, stay for 5 seconds, and observe if there is any change in the pointer. If the pointer does not drop within 5 seconds, it indicates that the valve is holding pressure normally. Second, the hydraulic check valve is installed in the automatic pressure maintaining tester. After startup, the hydraulic check valve is compressed and the pressure value will be automatically displayed on the pressure gauge of the equipment. If the pressure value is fixed for 5 seconds and the pointer does not change again, it indicates that the hydraulic check valve pressure maintaining test has passed. Most hydraulic check valve manufacturers only do one testing on the valve for pressure holding performance, while AAK conduct testing in 2 steps. The first step is to test the valve body to ensure that there is no leakage during the installation process. The second step is to measure the pressure holding capacity of the entire valve, including the fit between the valve spool and valve cage. AAK hydraulic check valve, focuses on stable manufacturing quality, and has 2 tests for pressure holding to avoid leakage. You can give it a try! AAK HYDRAULIC CARTRIDGE VALVES (691) 2023-10-12 https://www.aakindustry.com/info , -detail/check-valves-aak691