The Chinese and Asian Art Forum. For Fans, Collectors and Dealers.

Basic Rules For the BidAmount Asian Art Forum: Talk about whatever you want. You can even discuss and offer things that are for sale if they are authentic. Maximum image file size per post is 2 MB. Images of 700pxl x 700pxl are optimal if saved at a medium resolution. Be respectful of others and enjoy yourself. Click the YouTube link for a brief tutorial on using the forum. You can also EMBED Videos by cutting and pasting from You-Tube, Vimeo etc.

NOTE: To post an item or add a new post, click open the category title from the FORUM LIST, and CLICK the Blue ADD TOPIC button.

sf fas

Group: Registered

Joined: 2021-12-30

New Member

About Me

http://www.aborflow.com/pump/

Characteristics of Centrifugal Pumps

Pumps are generally

grouped into two broad categories—positive displacement pumps and dynamic

(centrifugal) pumps. Positive displacement pumps use a mechanical means to vary the

size of (or move) the fluid chamber to cause the fluid to flow. On the other hand,

centrifugal pumps impart momentum to the fluid by rotating impellers that are

immersed in the fluid. The momentum produces an increase in pressure or flow at the

pump outlet.

Positive displacement pumps have a constant torque characteristic, whereas

centrifugal pumps demonstrate variable torque characteristics. This article will

discuss only centrifugal pumps.

A centrifugal pump converts driver energy to kinetic energy in a liquid by

accelerating the fluid to the outer rim of an impeller. The amount of energy given

to the liquid corresponds to the velocity at the edge or vane tip of the impeller.

The faster the impeller revolves or the bigger the impeller, then the higher the

velocity of the liquid at the vane tip and the greater the energy imparted to the

liquid.

Characteristics

Creating a resistance to the flow controls the kinetic energy of a liquid

coming out of an impeller. The first resistance is created by the pump volute

(casing), which catches the liquid and slows it down. When the liquid slows down in

the pump casing, some of the kinetic energy is converted to pressure energy. It is

the resistance to the pump’s flow that is read on a pressure gauge attached to the

discharge line. A pump does not create pressure, it only creates flow. Pressure is

a measurement of the resistance to flow.

Head—Resistance to Flow

In Newtonian (true) fluids (non-viscous liquids, such as water or gasoline),

the term head is the measurement of the kinetic energy that a <a

href="http://www.aborflow.com/pump/centrifugal-pump/" target="_self">centrifugal

pump creates. Imagine a pipe shooting a jet of water straight into the air. The

height that the water reaches is the head. Head measures the height of a liquid

column, which the pump could create resulting from the kinetic energy the

centrifugal pump gives to the liquid. The main reason for using head instead of

pressure to measure a centrifugal pump’s energy is that the pressure from a pump

will change if the specific gravity (weight) of the liquid changes, but the head

will not change. End users can always describe a pump’s performance on any

Newtonian fluid, whether it is heavy (sulfuric acid) or light (gasoline), by using

head. Head is related to the velocity that the liquid gains when going through the

pump.

All the forms of energy involved in a liquid flow system can be expressed in

terms of feet of liquid. The total of these heads determines the total system head

or the work that a pump must perform in the system. The different types of head—

friction, velocity and pressure—are defined in this section.

Gear Pump Operation and Maintenance

1. Introduction

A gear pump uses two meshing, toothed cogs to force water from the inlet of

the pump through to the outlet. Figure No. 1 shows a simplified drawing of an

external teeth <a href="http://www.aborflow.com/pump/gear-pump/"

target="_self">gear pump on the left along with the alternate arrangement of

internally pointing teeth.

2. Gear pump Design

Gear pumps use toothed gears turning inside a close tolerance housing to draw-

in liquid and then squeezing it out ahead of them. Paddle steamers used the same

principle of operation. These pumps are positive displacement pumps and anything

drawn into them will be forced out. As a consequence they can generate very high

discharge pressures. Materials of construction vary from metals of various types

and hardness through to plastics of various types and hardness.

Maintaining the close tolerances between the housing and the cogs is critical

to efficient operation. The clearance between the edges of the teeth and the

housing and the ends of the cogs and the back and front walls of the housing are

very small. Between the teeth and housing it is in the order of 0.1 mm (0.004”)

while the clearances between the front and back faces of the gears and the ends of

the housing are only 0.025 mm (0.001”). The fine clearances reduce liquid re-

circulation back from the high-pressure discharge to the low-pressure suction side

and make these pumps one of the most efficient available.

Gear pumps usually have one shaft penetration through the housing for

connection to the drive. The gear shafts on the smaller pumps can be supported in

journal bearings within the ends of the housing and are lubricated by the product.

On larger pumps rolling element bearings mounted in bearing housings are used. To

prevent surface to surface contact wear of teeth the product does the lubrication.

3. Gear pump Uses

The design of a gear pump lends itself to use with clean liquids. Insure they

draw liquid from well above the bottom of the supply tank in clear liquid space.

Both low and high viscosity liquids can be pumped. If food grade <a

href="http://www.aborflow.com/" target="_self">products sensitive to shear

(i.e. where the churning action of the pump breaks cells and fibres) are to be

pumped the size of the pump will need to be increased and the speed reduced.

The design also produces good suction characteristics and they can be used to

draw clean, low viscosity liquids from a good depth or distance. Where high

viscosity liquids are pumped, or if drawing from a depth or distance, make it easy

for the liquid to flow into the pump. Install large diameter suction lines, keep

them short and where possible always put the pump lower than the supply tank so the

suction is under positive head pressure from the stored liquid.

The very fine tolerances prevent pumping anything with a solid or particulate,

as it would be squashed between the teeth and destroy the pump. If there is risk of

solids being drawn into the pump it is necessary to install a suction line strainer

that can be easily cleaned. Use as fine mesh screen as is possible without greatly

increasing the suction pressure loses else the pump will cavitate. If the

particulate is so fine that it passes through the screen it is better to choose a

different design of pump.

Being a positive displacement pump there deliver very precise quantities for

each revolution and this means they have good dosing characteristics regardless of

their speed. Gear pumps make good chemical additive dosing pumps provided material

compatibility issues are addressed.

4. Gear pump Installations

When using a gear pump a pressure relief valve must be fitted to protect the

pump if deadheaded against a closed <a href="http://www.aborflow.com/valve/"

target="_self">valve or blockage. The PRV can be piped back to the suction side

of the pump or into the supply tank.

Pumps driven by belt drives have the added protection that the belts will slip

in the pulleys if the pump is deadheaded. Insure bearings with a heavy-duty radial

load carrying ability are installed if the pump is to be belt driven. If a drive

coupling is used between the motor and the pump it is critical to align the shafts

precisely to within 0.05 mm (0.002”) from motor shaft end to pump shaft end using

laser or reverse dial indicator methods. Shaft misalignment produces orbital motion

that loads the bearings and distorts the shaft as it turns. Flexible shaft

couplings will transmit these loads.

These pumps require solid, firm mounts on solid metal bases and plinths. If

direct in-line drive through a shaft coupling is used the entire pump set must be

mounted on a solid steel frame with pump feet positions machined flat to within

0.025 (0.001”) tolerance

5. Maintenance Issues

Gear pumps require good, robust installation, a PRV to protect the pump from

overpressure and an assured supply of clean liquid. Those with outboard bearings

require the bearings to be lubricated. Mechanical seals introduce there own set of

problems and if possible select pumps that do not use them. If mechanical seals are

fitted it becomes critical that shafts run true and the process pressures and flows

are steady and do not fluctuate wildly to load up the bearings and gear teeth

unevenly.

The gear teeth must not be run dry. Unlubricated teeth will rub together and

wear away. If these pumps are run dry and temperatures rise the cogs will expand

and start rubbing on the housing. This will tear-up the housing and teeth. Either

the pump is destroyed or the fine housing clearances are lost which then allows

recirculation within the pump. The best protection against dry running is to

install a flow switch in the suction line that turns power off to the pump if there

is no flow.

Ball Valve - How They Work

A ball

valve is a shut off valve that controls the flow of a liquid or gas by means of

a rotary ball having a bore. By rotating the ball a quarter turn (90 degrees)

around its axis, the medium can flow through or is blocked. They are characterized

by a long service life and provide a reliable sealing over the life span, even when

the valve is not in use for a long time. As a result, they are more popular as a

shut off valve then for example the gate valve. For a complete comparison, read our

gate valve vs ball valve article. Moreover, they are more resistant against

contaminated media than most other types of valves. In special versions, ball

valves are also used as a control valve. This application is less common due to the

relatively limited accuracy of controlling the flow rate in comparison with other

types of control valves. However, the valve also offers some advantages here. For

example, it still ensures a reliable sealing, even in the case of dirty media.

What are the different types of Butterfly valves?

Each of the three different types of Butterfly valves are adapted to work with

different pressures and usage. They include:

Zero offset Butterfly valves which have the lowest pressure rating and relies

on the flexibility of rubber

Double offset Butterfly valves which are used in slightly higher-pressure

systems which, by creating a cam action during operation to lift the seat out of

the seal, produces less friction, reducing the tendency for wear and results in

high performance

Triple offset Butterfly valves which are best suited for high-pressure systems.

Why are butterfly valves good for use as a fluid flow control valve?

One of the key features that promote Butterfly valves as a fluid flow control

valve is that they are smaller and weigh less than the alternatives. Providing they

are sized correctly, Butterfly valves can offer a wider control range than similar

valves, such as globe or ball valves and take up less space.

As well as the size and weight advantages, Butterfly valves also have a higher

capacity and lower flow restrictions. They are also the valve of choice for

economical reasons as they offer lower installation costs. This is down to

Butterfly valves being line size and not requiring pipework reducers.

Applications where Butterfly valves can be used as a fluid flow control valve

There is a wide range of applications for when <a

href="http://www.aborflow.com/valve/butterfly-valve/" target="_self">Butterfly

valves are ideal for use as a fluid flow control valve. They can be used for

capacity lines on shops and perform well within slurry and water applications with

high volume.

Some of the applications, where the different types of Butterfly valves that BM

Engineering stock, can be used include:<br style="box-sizing: border-box; margin-

bottom: 0px;"/>Cooling water, air, gases and fire protection

Slurry

Vacuum services

High pressure, temperature water, and steam services

Compressed air applications

Compressed gas applications.

Occupation

http://www.aborflow.com/pump/

Social Networks

Member Activity

Forum Posts

Topics

Questions

Answers

Question Comments

Liked

Received Likes

Received Dislikes

0/10

Rating

Blog Posts

Blog Comments

Thanks for visiting "The BidAmount Asian Art Forum | Chinese Art"

If you sell on eBay, or have a shop feel free to post images and descriptions and links.

Check back often for discussion about the latest news in the Chinese art and antique world. Also find out about the latest Asian art auctions at Sotheby's, Christie's, Bonhams and Tajans.

Auction results for: fine porcelain, ceramics, bronze, jade, textiles and scholar's objects. As well as Japanese, Thai, Vietnamese and other Asian cultures.

Thank you,

Peter Combs

Topics and categories on The BidAmount Asian Art Forum | Chinese Art

Kangxi vases, Kangxi dishes and chargers, Kangxi ritual pieces, Kangxi scholar's objects, Qianlong famille rose, Qianlong enamels, Qianlong period paintings, Qianlong Emporer's court, Fine porcelain of the Yongzheng period. Chinese imperial art, Ming porcelain including Jiajing, Wanli, Xuande, Chenghua as well as Ming jades and bronzes.

Join the BidAmount Chinese and Asian art discussion board and forum today

The BidAmount Asian Art Forum | Chinese Art

A free Asian art discussion board and Asian art message board for dealers and collectors of art and antiques from China, Japan, Korea, Thailand, Cambodia, Vietnam and the rest of Asia. Linked to all of the BidAmount Asian art reference areas, with videos from plcombs Asian Art and Bidamount on YouTube. Sign up also for the weekly BidAmount newsletter and catalogs of active eBay listing of Chinese porcelain, bronze, jades, robes, and paintings.

Ancient Chinese Art - Ancient History Encyclopedia

The art of calligraphy - and for the ancient Chinese it certainly was an art - aimed to demonstrate superior control and skill using brush and ink. Calligraphy established itself as one of the major Chinese art forms during the Han dynasty (206 BCE - 220 CE), and for two millennia after, all educated men were expected to be proficient at it.

Arts of Asia | The Museum of Fine Arts, Houston

The Museum’s collections of Asian art span nearly five millennia and encompass the cultures of China, the Himalayas, India, Japan, Korea, and Southeast Asia. In 2007, the Museum launched an initiative to create dedicated galleries for the collection, beginning with a gallery for the arts of Korea ...

Chinese Art: Characteristics, History - Art Encyclopedia

Chinese art is full of symbolism, in that artists typically seek to depict some aspect of a totality of which they are intuitively aware.

China Online Museum - Chinese Art Galleries: Home

China Online Museum is the finest online museum of Chinese art. It features Chinese calligraphy, painting, ceramics, bronzes, carving, and other artworks.

Chinese Ceramics & Works of Art | Christie's

Chinese Ceramics & Works of Art. Overview Upcoming auctions Contacts Auction results ... Christie’s sales of Chinese ceramics and works of art showcase centuries of Chinese history. Held throughout the year in London, New York, Paris and Hong Kong, they attract a wide audience of collectors and connoisseurs vying for pieces as diverse as ...

Fine Chinese Paintings | Christie's

Explore Asian Art Week. Contact the Specialist Department. Chinese Paintings ... Senior Specialist, Head of Sale. ehammer@christies.com. Tel:+1 212 641 5760. Bid in-person or online for the upcoming auction:Fine Chinese Paintings on 10 September 2019 at New York. Bid in-person or online for the upcoming auction:Fine Chinese Paintings on 10 ...

Asian Art Week | New York | September 2019 | Christie's

Discover an abundance of must-see art from all corners of a vast continent at Christie’s NY Asian Art Week. From contemporary classical and Chinese paintings to works with exemplary provenance from the Art Institute of Chicago, our Rockefeller Paza galleries will be full of ancient treasures and contemporary masterworks in a salute to the vibrant arts of Asia.

Chinese Art from The Art Institute of Chicago | Christie's

Sold to benefit The Art Institute of Chicago’s Asian Art Acquisition Fund, the sale features 84 lots with a focus on Ming and Qing porcelains, and offers a rare insight into the taste for collecting Chinese ceramics and works of art in the Midwest from the end of the 19th century through the 1980s. Highlights include two Wanli wucai garlic-head vases, a Qianlong mark and period, blue and ...

Chinese Art in Hong Kong: A Brief ... - Christie's Education

Specialist, Chinese Paintings, Christie's London Dr Malcolm McNeill is a Specialist in Chinese Paintings at Christie’s, based in London. He previously worked as an assistant curator of the Chinese collections and the Victoria and Albert Museum in London, as a researcher at the British Museum, and as a translator and tour guide at the National Palace Museum in Taipei.

The Christie's Education 2020 Conference: The Chinese Art ...

The Christie's Education 2020 Conference: The Chinese Art Market 18 Jun 2019 Christie’s Education is delighted to announce our first international academic conference in Asia which will take place in Hong Kong from 26-27 November 2020 at the Hong Kong Convention and Exhibition Centre and will run in parallel with Christie’s Hong Kong Autumn Auctions.

Chinese Art | Sotheby's

The summer Chinese Art sale in Hong Kong will feature works of art from several private collections, including Qing porcelains and textile from the collection of the legendary Chinese art dealer A. W. Bahr (1877–1959), fine gilt bronze Buddhist sculptures from an old Hong Kong collection, an East Asian collection of Qing dynasty wine cups and jades, and a Japanese collection of Song ceramics ...

Chinese Art Auctions - Chinese Paintings ... - Sothebys.com

Sotheby's Chinese Works of Art Department holds two auctions each year in London, New York, Hong Kong and Paris.

Chinese Art | Sotheby's

Chinese Art - View Auction details, bid, buy and collect the various artworks at Sothebys Art Auction House.

Important Chinese Art | Sotheby's

With more than 340 Chinese works of art dating from the Neolithic to the Republic periods, highlights of this sale include a selection of Qing Imperial monochromes from the collection of Arnold and Blema Steinberg, early ceramics from the Art Institute of Chicago and Chinese porcelain and works of art from the collection of Henry Arnhold.

Important Chinese Art | Sotheby's

Results: Sotheby's Asia Week achieved $52.4 million in six strong auctions, exceeding pre-sale estimates. With 76.5% of lots sold and 60.3% of lots surpassing high estimates, the Asian art sales at Sotheby's indicate continued collector interest in the finest works of art from China, India and and the Himalayas.

Important Chinese Art | Sotheby's

Today's sale of Important Chinese Art will proceed as planned with sessions at 10 AM and 2 PM EDT. Sotheby's will be monitoring the weather conditions throughout the day and will be available to coordinate alternative bidding options should conditions make it difficult for clients to attend the auction in person.

Bonhams : Chinese Works of Art

Bonhams Chinese Art department is renowned for offering the finest works of art representing the richness and breadth of China's artistic heritage, particularly Imperial porcelain, white and spinach green jades, cloisonné and Buddhist art. Specialised international auctions are held globally, including London, Hong Kong and San Francisco.

Bonhams : Chinese Works of Art

Bonhams : Chinese Works of Art We use cookies to remember choices you make on functionality and personal features to enhance your experience to our site. By continuing to use our site you consent to the use of cookies. Please refer to our privacy and cookie policies for more information.

Bonhams : Fine Chinese Paintings and Works of Art

Bonhams Fine Art Auctioneers & Valuers: auctioneers of art, pictures, collectables and motor cars. We use cookies to remember choices you make on functionality and personal features to enhance your experience to our site. By continuing to use our site you consent to the use of cookies. ... Chinese Art (US) General enquiries

Bonhams : Fine Chinese Art

Bonhams : Fine Chinese Art We use cookies to remember choices you make on functionality and personal features to enhance your experience to our site. By continuing to use our site you consent to the use of cookies. Please refer to our privacy and cookie policies for more information.

Bonhams : Asian Art

Bonhams Fine Art Auctioneers & Valuers: auctioneers of art, pictures, collectables and motor cars Bonhams : Asian Art We use cookies to remember choices you make on functionality and personal features to enhance your experience to our site.

Bonhams | Asian Art in London

Bonhams are international auctioneers of fine Chinese and Japanese art. We specialise in rare Imperial and Export Chinese ceramics and works of art, as well as Japanese ceramics, fine and decorative works of art from the Neolithic Period to the 20th century. View on map

Bonhams : Asian Art

The BidAmount Asian Art Forum | Chinese Art

The Chinese and Asian Art Forum. For Fans, Collectors and Dealers.

NOTE: To post an item or add a new post, click open the category title from the FORUM LIST, and CLICK the Blue ADD TOPIC button.

Super Globals

Options and Features

Thanks for visiting "The BidAmount Asian Art Forum | Chinese Art"

Topics and categories on The BidAmount Asian Art Forum | Chinese Art

The BidAmount Asian Art Forum | Chinese Art