Piping: Chapter 3
Bending Pipe Part - 1
In this module, we will learn about finding the correct angle of bend from the blueprint.We will also learn about tools used for bending the pipe at desired angle. Skip to quiz!
Determine Bend Angle
Recall that pipes are used for high temperature applications in HVAC system.ipes carry high-temperature fluids such as refrigerant from one component to the other.
Recall that refrigerant travels from evaporator to the compressor through pipes. These components are located away from each other. To clear obstacles in their route we need to bend the pipe.
A pipe bend means a piece of pipe that is bent to some angle. We bend the pipe based on:
Space available
Blueprint
We take the help of a blueprint in case of commercial HVAC systems.
Recall that pipe length is decided based on the space available. Bend angle of the pipes can also be decided by the space available between two components.
For example, if the space for the bend is narrow a 45-degree bend may be required. However, if space is more narrow, then a 90-degree bend is best suited to occupy in that space. As seen in the image, 90 degree bend is used to serve the purpose.
Recall that blueprint is the map of HVAC system. We can also find angle of piping based on a blueprint. Let's see how we can make use of blueprint for finding the bend angle.
The image shows the blueprint of the HVAC system. It has different pipes connected. The angle of bend is specified near the bend.
For example, bend angle of green pipe is 90 degrees. Similarly, blue pipe is bent at an angle of 45 degrees.
Bending Tools
We now know, how to determine the bend angle. Let us look at how to bend the pipe to the desired bend angle.
A bending tool is used to bend the pipe. These tools are manually operated and do not require electricity.
There are several types of bending tools including:
Spring Bender,
Ratchet Bender, and
Hand Bender
We will go over spring bender in this topic.
Spring Bender
A spring bender is a large spring. This spring can be placed over outside of the pipe. We can also insert the spring inside the pipe to bend the pipe.
When you insert a flexible spring into a pipe or over a pipe, it supports the pipe surface. We can then start bending the pipe manually, around our knee. The spring prevents the pipe from bending too much or breaking.
Depending on the spring position there are two types of spring benders:
External spring bender, and
Internal spring bender
The spring benders are used according to the size of pipe. We need to select right size of the spring bender according to size of the pipe.
For example, external spring bender is used on pipes with a diameter less than 0.6 inches. Internal spring bender is used for a diameter in the range of 0.6 inches to 0.8 inches.
So, we should always measure pipe diameter before using spring bender. The spring bender cannot bend pipes larger than 0.8 inches. This is because we cannot bend thick and strong pipes by hand.
External spring bender is inserted externally over the pipe. This is why it is called external spring bender.
On an external bending spring, the tapered end is wider. This makes it easier for us to insert the pipe inside the spring. Let us see how to use them for bending pipe.
Feed the pipe into the spring via the wider tapered end Apply pressure to the ends of the pipe and gently form the desired bend.
Note that bending too quickly or powerfully will result in wrinkled pipe. The image shows a wrinkled bend.
Slide the spring off the pipe. If you find this difficult, try twisting as you pull to loosen the spring.
Internal spring bender is inserted internally into the pipe. This is why they are called internal spring bender.
The tapered end of an internal bending spring is slightly thinner. This allows you to feed the spring into the pipe with ease.
Internal pipe bending spring will have a ring on one end. This allows you to attach a piece of wire or string to it. This makes it easy to retrieve the spring after each use.
Feed the spring into the pipe via the narrower tapered end. Make sure you leave a ring end out so that you can retrieve it again afterwards.
If you need to insert the pipe bending spring all the way into your pipe, attach a piece of strong string or wire to the ring end. We can pull the spring out with the help of string or wire.
Locate the place where you want to bend. Place it against your knee. Gently pull back on the ends of the pipe until the desired angle is created.
Retrieve your spring from inside the pipe. Recall that twisting the spring while removing helps loosen the spring. Pull the wire or string on the ring end to remove the spring out.
A spring bender is very easy to operate than other bending tools. We only need to insert the spring into the tubing or over the tubing.
A spring bender can cause injury to the user’s knees if bending is a daily occurrence. Also, bending spring cannot bend pipes larger than 0.8 inches. These pipes are too thick and strong to bend solely by hand.
The blueprint is the map of HVAC system. It is used to find angle of the pipe bend. External spring bender is used on pipes with a diameter of less than 0.6 inches. Internal spring bender is used for a diameter in the range of 0.6 inches to 0.8 inches.
Bending Pipe Part - 2
We saw what is a spring bender in the previous module.In this module, we will go over the other bending tools used for bending the pipe:
- Ratchet bender, and
- Hand bender
We will also learn about the safety while using these tools. Skip to quiz!
Ratchet Bender
Recall that a spring bender is used to bend pipes manually by hands. So, they cannot make accurate bends. We will look into a more advanced pipe bending tool called a ratchet bender.
A ratchet bender is a tool used to bend pipes at a desired angle. They can bend the pipe upto 90 degrees. Instead of using manual force, it uses lever to bend the pipe.
This type of pipe bender is useful in tight spaces. In tight spaces, it is impossible to bend the pipe manually because of space constraints. Also, it may be impossible to use or handle other pipe benders.
Imagine bending a pipe that is already positioned against a wall. A ratchet bender can easily fit in such places.
The ratchet bender has following parts.
Bending shoe,
Cross bar assembly,
Ratchet trigger, and
Handle
Let us look into each one of them.
The bending shoe of the ratchet pipe bender is used to shape the pipe in desired angle. It is attached to the handle of the ratchet pipe bender.
The bending shoe is marked with the pipe sizes. You need to select the correct size of shoe as per diameter of pipe.
For example, we need to select ½ inch bending shoe for a ½ inch pipe. This will ensure the pipe fits inside the shoe.
Cross bar supports the pipe during bending. There are two side blocks that are mounted on the cross bar.
These side blocks need to be adjusted by turning clockwise. This ensure that side blocks align the pipe you are bending. When you bend the pipe, they keep the pipe in place.
The ratchet trigger is connected to the tool’s handle. With each squeeze, the bending shoe is pushed further upwards.
The ratchet handle has a square metal bar. Bending shoe is connected to these metal bar. Let us look at how to use this tool to bend the pipe.
As seen in the video, start by identifying the correct size bending shoe. Attach the bending shoe to your ratchet pipe bender.
Now, attach the cross bar assembly on the ratchet handle. Adjust the slide blocks to make sure they are aligned with the bending shoe.
Put the pipe between the sliding blocks and the bending shoe. Squeeze the ratchet trigger a few times to start bending. Continue squeezing the lever until the bend is complete.
To remove the tube, pull the ratchet trigger away from you. Push the bending shoe down slightly to allow you to pull out the pipe.
Hand Bender
A hand bender has a long handle that is pulled to create bends. Hand benders can be used to bend the pipe at more than 90 degrees angle. They can bend up to 180 degrees.
The hand bender consists of following parts:
Vice clamp block,
Bender die,
Tube latch, and
Carriage and form handle
A vice clamp block fixes the hand bender in one place. This feature is helpful when bending long tubing.
Recall that the bending shoe of the ratchet pipe bender is used to shape the pipe in desired angle. Bender die also shapes the pipe to the desired angle.
Tube latch is used to clamp the tube. This restricts movement of the tube while bending.
Recall that leverage is increase in force. The long carriage handle provides leverage to bend the pipe with dominant hand. The form handle is used to grasp the bender in other hand.
There is a scale on the ends of former and carrier handle. The scale attached at the end of carriage handle is carrier scale. The scale attached at the end of form handle is former scale.
The former scale is used to denote bend angle. Whereas, carrier scale shows the start of bend.
For example, we need to mark the tube at the desired distance (X) from the end of tube. This is the location of bend centre. If the length of bend from tube end is to the left of bend centre you need to align the ‘’X’’ distance mark with “L” on carrier scale.
Similarly, If the length of bend from tube end is to the right of bend centre you need to align the ‘’X’’ distance mark with “R” on carrier scale. That is how carrier scale is useful to decide start of bend for accurate bend start length from end of pipe.
We need to follow the following steps while using a deburring tool:
Step 1: Grasp the bender by the form handle or mount the bender in vise.
Step 2: Move carriage handle away from the form handle.
Step 3: Open the tube latch and insert the pipe.
Step 4: Close the tube latch.
Step 5: Rotate the carriage handle around the form handle.
This is rotated until the “0” line on the carriage scale aligns with the desired degree of bend on the former scale. This way we bend the pipe using hand bender.
Mark the tube at the desired distance (X) from the end of tube. This distance is the center of the bend from the end of tube. Place the tube in the bender as described in steps 1-5 above.
If the bend is to the left of the mark, align the mark on the tube with the “L” line on the carriage scale. If the bend is to the right of the mark, align the mark on the tube with the “R” line on the carriage scale.
With the mark on the tube appropriately aligned, move the carriage handle. We need to move it until “0” line on the carriage scale aligns with the 90 degree line on the form scale. We can also make 45 degree bend in the similar manner. Let us see how to do that.
Repeat the same procedure for placing the tube in the bender as described in steps 1-5 above. Align the mark on the tube with the “L” line or “R” line on carriage scale.
With the mark on the tube appropriately aligned, move the carriage handle. We need to move it until “0” Line on the carriage scale aligns with the 45 degree line on the form scale. This way we bend the pipe at 45 degrees using a hand bender.
Pipe Bender Safety
We should always follow general safety guidelines while bending the pipe. Protecting yourself using Personal Protective Equipment (PPE) is a must in the workplace.
We should always use safety glasses to reduce the risk of eye injury. Wear gloves to protect hand cuts from sharp edges of pipes and tools. Use safety shoes to avoid injuries from sharp objects that can prick your feet.
We should inspect the bender before each use for damage. The bender should be properly cleaned. This will prevent slipping of handles from your grip during use.
We need to lubricate all the joints of the bender to ensure that it works smoothly. We need to make sure the bender is completely and properly assembled.
We should not exceed the capacity or pipe size stated by pipe bender’s manufacturer. Read the user manual for the pipe bender to know its capacity.
We should not use handle extensions such as a piece of pipe for leverage. If it slips or comes off, it can increase the risk of serious injury.
Ratchet Bender can bend the pipe upto 90 degrees. Hand benders can be used to bend the pipe at more than 90 degrees angle. Safety precaution is followed while using any of these tools.
Question #1: A blueprint shows _________. (Select all that apply)
Bend angle of the pipe
Length of the pipe
Material of the pipe
Temperature of the pipe
Scroll down for the answer...
Answer: Bend angle of the pipe
Length of the pipe
A blueprint is the map of HVAC system. It shows the the location, length and bend angle of the pipe used in HVAC system.
Question #2: External spring bender is inserted internally over the pipe.
True
False
Scroll down for the answer...
Answer: False
External spring bender is inserted externally over the pipe.
Question #3: How to pull back the spring from the place after bending?
Twisting the spring while removing
Using spring remover
Using blueprint
Placing the spring against your knees
Scroll down for the answer...
Answer: Twisting the spring while removing
Twisting the spring while removing helps loosen the spring. It will help the spring to come off easily.
Question #4: What is the use of bending shoe?
To shape the pipe
To remove the pipe
To rotate the pipe
To attach side blocks
Scroll down for the answer...
Answer: To shape the pipe
The bending shoes of the ratchet pipe bender is used to shape the pipe in desired angle. It is attached to the handle of ratchet pipe bender. The bending shoes are marked with the various tube sizes.
Question #5: What is the function of side blocks?
To shape the pipe
To keep the pipe in place while bending.
To rotate the pipe
To loosen the pipe
Scroll down for the answer...
Answer: To keep the pipe in place while bending.
Recall that side blocks need to be adjusted by turning clockwise.
They keep the pipe in place while bending.
Question #6: Ratchet trigger has square metal bar that is used to connect bending shoe.
True
False
Scroll down for the answer...
Answer: False
Recall that The ratchet handle has a square metal bar. Bending shoe is connected to these metal bar.
Question #7: How do you remove the tube after bending operation is completed?
Rotate cross bar assembly
Pull the ratchet trigger away from you
Slide the tube sidewards
Hold the ratchet handle and rotate bending shoe
Scroll down for the answer...
Answer: Pull the ratchet trigger away from you
To remove the tube, pull the ratchet trigger away from you. Push the bending shoe down slightly to allow you to pull out the pipe.
Question #8: Hand bender can be used to bend the pipe at an angle of_________.
90 degrees
More than 90 degrees
75 degrees
-60 degrees
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Answer: More than 90 degrees
Hand benders can be used to bend the pipe at more than 90 degrees angle.
Ratchet Bender can bend the pipe upto 90 degrees.
Question #9: What is the use of former scale?
To show length of pipe
To show bend angle
To show carriage handle strength
To make small circles
Scroll down for the answer...
Answer: To show bend angle
Recall that the scale attached at the end of form handle is former scale. This scale is used to denote bend angle.
Question #10: What is the use of carrier scale?
To show start of bend
To show bend angle
To show carriage handle strength
To make small circlesScroll down for the answer...
Answer: To show start of bend
Recall that the scale attached at the end of carriage handle is carrier scale. This scale is used to denote start of bend.
Question #11: How can 100 degree bend be formed using hand bender?
By rotating carriage handle until the “0” line on the carriage scale aligns with the 100 mark on former scale.
It is not possible to bend more than 90 degrees.
Using bender die of 100 degree
By rotating carriage handle until the “0” line on the carriage scale aligns with the 10 mark on former scale.
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Answer: By rotating carriage handle until the “0” line on the carriage scale aligns with the 100 mark on former scale.
The carriage handle is rotated until the “0” line on the carriage scale aligns with the desired degree of bend on the former scale.
In this case, for 100 degrees the ‘0’ line on carriage scale should align with 100 mark.