A flange is a category of gasket made to fix two sections of pipe together, or act as a removable plug at the end of a single pipe. All flanges are round disks with holes for bolts around the rim, but the commonalities end there. There is a variety of flanges to suit every purpose, from blocking high-pressure pipes to attaching two pipes of incompatible material. Also known as pipe flanges or flange gaskets, flanges are most often selected in place of other fittings to make cleaning and repairs more feasible.

Blind Flange

The simplest, most straight-forward flange in design, a blind flange is a solid disk used to block the end of a pipe. It’s anomalous in that most flanges are open in the center, allowing the contents of the pipe to move through it. Sometimes, there is a slight indent around the rim, creating a niche for the pipe to fall into. Blind flanges are also known as blank flanges, and referred to as flat face or raised face depending on the presence of an indent.

Weld Neck Flange

Named after the neck shape protruding from the center, a weld neck flange is designed for quick welding. The neck, which extends from the center, is thin and malleable in order to melt quickly. It’s generally butt-welded to the pipe before the disk portion of the flange is affixed to the rim with bolts.

Slip-on Flange

The one-piece version of the lap joint flange, the slip-in flange has a short length of pipe extruding from one end, creating a sleeve for a pipe to nestle into. The pipe is then fillet-welded both along the disk and the inner rim of the flange, adding extra support. 

Lap Joint Flange

The close cousin of the slip-on flange, the lap joint flange comes in two pieces: a disk with a hollow center and a neck piece which fits perfectly inside the hole. This second piece, called the stub-end, is secured to a pipe using a fillet weld.

Threaded Flange

The same shape as a slip-on flange, a threaded flange is a disk with extra material extruding from one end, plus threading to feed the pipe onto the flange. Unlike most flanges, they can be securely attached with or without welding, making them perfect for pipe sections that need regular cleaning. 

Socket Weld Flange

Following the basic design of the slip-on flange, the socket weld flange gets its name from the shoulder, or extended rim at the end of the stub-end. When installed, the pipe is nestled inside the socket of the flange and welded into place. The socket helps steady the pipe during the welding process, and add additional surface area for a successful weld.

Orifice Flange

An orifice flange is a specialized piece designed to house an orifice meter. The basic design is two weld neck flanges back to back, with a gap in the center for the meter. An orifice meter is an excellent tool for tracking the flow speed within a pipe, making this somewhat complex flange a worthy investment. 

Expander Flange

Designed to serve as both a gasket and a reducer, an expander flange is a weld neck flange with a hub that widens at the far end. The neck, working as a funnel, channels the contents into the small opening at the base of the flange, where it’s bolted to the next section of pipe. 
If we don’t have your flange in stock, we will make it to order. We are also glad to consult on the types of flanges and other pipe fittings needed for your project. Please contact us so we can get started building your custom fittings ASAP.

On the microscopic level, high-density polyethylene has a clean, linear structure that makes the plastic light and strong. It can be manufactured and shipped at low costs, saving companies millions in materials. The simple material is waterproof, UV-resistant, and flexible under pressure, making it the perfect material for numerous uses.

Cost-Effective Uses of HDPE Sheets

Piping

HDPE is commonly recognized as the most cost-effective piping material. Pipe-grade HDPE retains its flexibility at temperatures down to -220˚ Fahrenheit, making it a great candidate to distribute cold liquids underground.

 

What the plastic is infamous for is being tricky to bond. Luckily, bonding techniques have been perfected since HDPE’s invention in the 1930’s. The most cost-effective technique is called electrofusion. Two pipe components are fitted together with a specially designed electrofusion fitting, which is then slowly heated to the melting point. The two pipes then weld into one.

Food Containers

Where HDPE shines brightest is in the consumable goods industry. It’s flexible, strong, and non-leaching. That makes it the perfect container for everything from cereal to ice cream. Best of all, consumers can drop HDPE containers right into the recycling bin when they’re done.

Unlike PVC and polystyrene, HDPE does not leach into water, making it a safe and healthy food container. Not surprisingly, HDPE is the preferred material for baby bottles and disposable cups.

Chemical Bottles

HDPE does not interact with most chemicals. It can safely contain laundry detergent, household cleaner, motor oil, or antifreeze. Adding a pigment to the plastic increases its strength and lengthens the shelf life of the product.

Toys

Being both durable and flexible, HDPE toys usually bounce instead of breaking. The material is safe for infants and toddlers as it does not leech in liquids. Being UV-resistant, HDPE also retains its color for longer than most plastics.

When Not to Use HDPE

This plastic is immune to most chemicals, but will oxidate in acids. For containing acids, we recommend PCTFE. PCTFE is a durable, waterproof plastic with a variety of uses, but is not as cost-effective as HDPE.

Like most plastics, HDPE melts quickly when exposed to open flame. When working with fire, there are two options. One is to treat the plastic with a flame-retardant layer. The other is to use metal instead of plastic.

HDPE is the best budget plastic. That is why it is the material of choice for consumable goods containers everywhere. To see where your company can save, consult Specified Fittings for free.

When selecting a type of plastic, you have to consider s strength, flexibility, heat resistance, and solubility. No single plastic is perfect for every use, but there is one plastic out there that can take on almost any job: HDPE.

HDPE, or high-density polyethylene, is the most widely used type of plastic in the world. This versatile material is in hard hats and shampoo bottles. It’s the lining of your cereal box and the jug of milk in your fridge. It can last for decades underground exposed to mold, mildew, insects, and rushing water. It’s not a question what HDPE can do. It’s a question what it can’t do.

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When something goes wrong with the plumbing, the key is finding the weak link or improper pipe fitting in the construction. Each pipe fitting has a specific job and must be able to handle the demands. Some must be able to withstand intense amounts of heat and pressure. Some must be water-tight while others must be air-tight. Pipe fittings must be compact, flexible, and sturdy enough to handle specific circumstances. The success of a project begins by selecting the right pipe fittings for the job.

Types of Pipe Fittings

Adapters and Bushings

An adapter creates a direct connection between two pipes of different diameters. Using a pipe fitting of this type cuts out a lengthy and complex process of attaching two dissimilar pipes. While an adapter has two male sides, a bushing has one male and one female side. In some cases, such as when two uncommon pipe varieties must be connected, an adapter or bushing must be custom-made. Adapters and bushings are equipped to handle high pressure, but their cousins, the coupling and the nipple, are not.

Caps and Plugs

To put it simply, a plug has threading and a cap does not. To stop low pressure water, a simple cap will do the trick. When the pressure is exceedingly high, such as inside a fire extinguisher, a sturdy plug must be screwed on tightly. It takes special equipment to remove a high pressure plug. Caps, on the other hand, may be glued or soldered permanently in order to prevent access.

Elbows

To avoid putting the pipes under unnecessary pressure, plumbing is built with straight lines of pipe. Any corner or angles are handled with an aptly named pipe fitting called the elbow. The most common elbow angles are 45 and 90 degrees, but they can be custom made to fit any situation. They can be screwed into place or glued to the adjacent pipes.  

Tees and Crosses

A tee or cross is any pipe fitting with more than two openings. A tee has 3 openings while a cross has 4. Both are used to facilitate a great variety of plumbing challenges. For example, water may come into a house in one pipe then split apart when it hits a tee. One pipe heads to the water heater while the other splits off around the house. Some tees and crosses have faucets attached so that water can pass through when the faucet is on but is blocked off when the faucet is off. There is no pump attached to the faucet, so the water pressure must be strong enough to force water up the pipe but not strong enough to break the plumbing.

A healthy pipe system is built with the right pieces. Whether the pipes are carrying hot gasses or high-pressure water, the demands can be very different. Each pipe fitting must be able to handle the challenges. When selecting a pipe fitting, the question is not just what it needs to be shaped like but what it needs to be able to handle.