Product Description
Product Description
Introduction
Pressure seal bonnet (PSB) globe valve relies on a sturdy special structure to ensure that the valve does not leak under the state of ultra-high working pressure, and that the seal will not be deformed or loose at the corresponding temperature. Due to the high pressure resistance and easy disassembly and maintenance, they are widely used in electric power, electrical, electromechanical equipment engineering, and electric control equipment engineering.
Features
1. The shell has high strength, reasonable structure and reliable sealing;
2. The sealing surface is abrasion resistant, with good sealing performance and long life;
3. Compact pressure seal bonnet and convenient maintenance;
4. The sealing surface of the valve disc and the valve seat is made of Stellite cobalt-based hard alloy surfacing welding, which is wear-resistant, high-temperature resistant, corrosion-resistant, scratch-resistant, and has a long service life;
5. After quenching and tempering and surface nitriding treatment, the valve stem has good corrosion resistance, scratch resistance and wear resistance;
6. The use of CZPT reinforced packing and efficient backseat design ensures that the valve stem is sealed without leakage.
Scope
| Nominal size | 2″~24″(DN50~DN600) |
| Nominal pressure | Class 900~Class 4500(PN160~PN420) |
| Standard: | ASME B16.34 |
| Body material | Carbon steel, Stainless steel, Alloy steel, Duplex stainless steel |
| End connection | RF, BW, RTJ, |
| Operation | Manual, Pneumatic, Electric, Hydraulic |
Product Parameters
Company Profile
Jitai Valve Group is a genuine valve manufacturer.
- 7000-sqm factory
- 100 employees
- 5+ senior engineers
- 30+ design patents
- 2 million sets of valves delivered
- 20 million USD annual revenue
Since 1988, we have been expert in manufacturing a wide scope of industrial valves including:
- Gate valves
- Globe valves
- Check valves
- Ball valves
- Butterfly valves
- API valves
- Steam valves
- High pressure valves
- High temperature valves
- Power Plant valves
Our Advantages
- Heavy-duty valve expert with proven expertise in harsh environment;
- Stringent quality control and traceable reports to provide zero-defect products;
- Rugged and durable configuration according to API, ASME, BS, JIS, EN standards;
- All kinds of UG, PRO/E, Solidworks software simulations ensure the efficiency and robustness for tailored components;
- Complete BV report can be downloaded on our page About us .
FAQ
1.Q:Are you are a trading company or manufacturer?
A:We are a manufacturer with 7000-sqm factory and 100 employees.
2.Q: Can you provide the assembly drawing for confirmation ?
A: Yes, we can give the relavant drawing within 24 hours.
3.Q: Can you do non destructive test for valve components ?
A: Yes, we can perform radiographic testing, penetration testing, ultrasonic testing, magnetic particle testing, etc
4.Q: How can I vist you when I am in China?
A: We are near the HangZhou Airport. If you take a plane, it takes 2 hours to reach our factory from ZheJiang , 2 hours from HangZhou, 3 hours from ZheJiang .
5.Q: Can we take sample for quality check?
A: Definitely. You can advise the model number and we will prepare the sample within 7 days.
6.Q: How can I become your distributor or agent?
A: You can send your company profile and reference list to our sales manager.
7.Q: Can you help with site maintenance and commissioning?
A: Yes, we are glad to offer our assistance whenever you need it. We can send our after sales team to address the issue within 14 days
Screw Shaft Features Explained
When choosing the screw shaft for your application, you should consider the features of the screws: threads, lead, pitch, helix angle, and more. You may be wondering what these features mean and how they affect the screw’s performance. This article explains the differences between these factors. The following are the features that affect the performance of screws and their properties. You can use these to make an informed decision and purchase the right screw. You can learn more about these features by reading the following articles.
Threads
The major diameter of a screw thread is the larger of the 2 extreme diameters. The major diameter of a screw is also known as the outside diameter. This dimension can’t be directly measured, but can be determined by measuring the distance between adjacent sides of the thread. In addition, the mean area of a screw thread is known as the pitch. The diameter of the thread and pitch line are directly proportional to the overall size of the screw.
The threads are classified by the diameter and pitch. The major diameter of a screw shaft has the largest number of threads; the smaller diameter is called the minor diameter. The thread angle, also known as the helix angle, is measured perpendicular to the axis of the screw. The major diameter is the largest part of the screw; the minor diameter is the lower end of the screw. The thread angle is the half distance between the major and minor diameters. The minor diameter is the outer surface of the screw, while the top surface corresponds to the major diameter.
The pitch is measured at the crest of a thread. In other words, a 16-pitch thread has a diameter of 1 sixteenth of the screw shaft’s diameter. The actual diameter is 0.03125 inches. Moreover, a large number of manufacturers use this measurement to determine the thread pitch. The pitch diameter is a critical factor in successful mating of male and female threads. So, when determining the pitch diameter, you need to check the thread pitch plate of a screw.
Lead
In screw shaft applications, a solid, corrosion-resistant material is an important requirement. Lead screws are a robust choice, which ensure shaft direction accuracy. This material is widely used in lathes and measuring instruments. They have black oxide coatings and are suited for environments where rusting is not acceptable. These screws are also relatively inexpensive. Here are some advantages of lead screws. They are highly durable, cost-effective, and offer high reliability.
A lead screw system may have multiple starts, or threads that run parallel to each other. The lead is the distance the nut travels along the shaft during a single revolution. The smaller the lead, the tighter the thread. The lead can also be expressed as the pitch, which is the distance between adjacent thread crests or troughs. A lead screw has a smaller pitch than a nut, and the smaller the lead, the greater its linear speed.
When choosing lead screws, the critical speed is the maximum number of revolutions per minute. This is determined by the minor diameter of the shaft and its length. The critical speed should never be exceeded or the lead will become distorted or cracked. The recommended operational speed is around 80 percent of the evaluated critical speed. Moreover, the lead screw must be properly aligned to avoid excessive vibrations. In addition, the screw pitch must be within the design tolerance of the shaft.
Pitch
The pitch of a screw shaft can be viewed as the distance between the crest of a thread and the surface where the threads meet. In mathematics, the pitch is equivalent to the length of 1 wavelength. The pitch of a screw shaft also relates to the diameter of the threads. In the following, the pitch of a screw is explained. It is important to note that the pitch of a screw is not a metric measurement. In the following, we will define the 2 terms and discuss how they relate to 1 another.
A screw’s pitch is not the same in all countries. The United Kingdom, Canada, and the United States have standardized screw threads according to the UN system. Therefore, there is a need to specify the pitch of a screw shaft when a screw is being manufactured. The standardization of pitch and diameter has also reduced the cost of screw manufacturing. Nevertheless, screw threads are still expensive. The United Kingdom, Canada, and the United States have introduced a system for the calculation of screw pitch.
The pitch of a lead screw is the same as that of a lead screw. The diameter is 0.25 inches and the circumference is 0.79 inches. When calculating the mechanical advantage of a screw, divide the diameter by its pitch. The larger the pitch, the more threads the screw has, increasing its critical speed and stiffness. The pitch of a screw shaft is also proportional to the number of starts in the shaft.
Helix angle
The helix angle of a screw shaft is the angle formed between the circumference of the cylinder and its helix. Both of these angles must be equal to 90 degrees. The larger the lead angle, the smaller the helix angle. Some reference materials refer to angle B as the helix angle. However, the actual angle is derived from calculating the screw geometry. Read on for more information. Listed below are some of the differences between helix angles and lead angles.
High helix screws have a long lead. This length reduces the number of effective turns of the screw. Because of this, fine pitch screws are usually used for small movements. A typical example is a 16-mm x 5-inch screw. Another example of a fine pitch screw is a 12x2mm screw. It is used for small moves. This type of screw has a lower lead angle than a high-helix screw.
A screw’s helix angle refers to the relative angle of the flight of the helix to the plane of the screw axis. While screw helix angles are not often altered from the standard square pitch, they can have an effect on processing. Changing the helix angle is more common in two-stage screws, special mixing screws, and metering screws. When a screw is designed for this function, it should be able to handle the materials it is made of.
Size
The diameter of a screw is its diameter, measured from the head to the shaft. Screw diameters are standardized by the American Society of Mechanical Engineers. The diameters of screws range from 3/50 inches to 16 inches, and more recently, fractions of an inch have been added. However, shaft diameters may vary depending on the job, so it is important to know the right size for the job. The size chart below shows the common sizes for screws.
Screws are generally referred to by their gauge, which is the major diameter. Screws with a major diameter less than a quarter of an inch are usually labeled as #0 to #14 and larger screws are labeled as sizes in fractions of an inch. There are also decimal equivalents of each screw size. These measurements will help you choose the correct size for your project. The screws with the smaller diameters were not tested.
In the previous section, we described the different shaft sizes and their specifications. These screw sizes are usually indicated by fractions of an inch, followed by a number of threads per inch. For example, a ten-inch screw has a shaft size of 2” with a thread pitch of 1/4″, and it has a diameter of 2 inches. This screw is welded to a two-inch Sch. 40 pipe. Alternatively, it can be welded to a 9-inch O.A.L. pipe.
Shape
Screws come in a wide variety of sizes and shapes, from the size of a quarter to the diameter of a U.S. quarter. Screws’ main function is to hold objects together and to translate torque into linear force. The shape of a screw shaft, if it is round, is the primary characteristic used to define its use. The following chart shows how the screw shaft differs from a quarter:
The shape of a screw shaft is determined by 2 features: its major diameter, or distance from the outer edge of the thread on 1 side to the inner smooth surface of the shaft. These are generally 2 to 16 millimeters in diameter. Screw shafts can have either a fully threaded shank or a half-threaded shank, with the latter providing better stability. Regardless of whether the screw shaft is round or domed, it is important to understand the different characteristics of a screw before attempting to install it into a project.
The screw shaft’s diameter is also important to its application. The ball circle diameter refers to the distance between the center of 2 opposite balls in contact with the grooves. The root diameter, on the other hand, refers to the distance between the bottommost grooves of the screw shaft. These are the 2 main measurements that define the screw’s overall size. Pitch and nominal diameter are important measurements for a screw’s performance in a particular application.
Lubrication
In most cases, lubrication of a screw shaft is accomplished with grease. Grease is made up of mineral or synthetic oil, thickening agent, and additives. The thickening agent can be a variety of different substances, including lithium, bentonite, aluminum, and barium complexes. A common classification for lubricating grease is NLGI Grade. While this may not be necessary when specifying the type of grease to use for a particular application, it is a useful qualitative measure.
When selecting a lubricant for a screw shaft, the operating temperature and the speed of the shaft determine the type of oil to use. Too much oil can result in heat buildup, while too little can lead to excessive wear and friction. The proper lubrication of a screw shaft directly affects the temperature rise of a ball screw, and the life of the assembly. To ensure the proper lubrication, follow the guidelines below.
Ideally, a low lubrication level is appropriate for medium-sized feed stuff factories. High lubrication level is appropriate for larger feed stuff factories. However, in low-speed applications, the lubrication level should be sufficiently high to ensure that the screws run freely. This is the only way to reduce friction and ensure the longest life possible. Lubrication of screw shafts is an important consideration for any screw.
