1- When use a globe valve or a gate valve?

2- What is the difference between a horizontal check valve and a swing check valve?

3- What is the meaning of the words "PN" and "DN" stamped in body valve?

4- How can I calculate the loss of charge in Mipel valves?

5- What is the Standard for the Mipel Relief Valves ( Figures 037 and 038 )?

6- Mipel Relief Valves ( Figures 037 and 038 ) can be used as Safety Valves?

7- What is the set range for Mipel Relief valves?

8- How many "MCW" ( meter water column ) can a Mipel Relief Valve support?

9- What is the maximum temperature that a Mipel Relief Valve support?

10- What is the class of pressure for the Mipel Ball Valves?

11- How to use the table "pressure x temperature" for Mipel Ball Valves.

12- What is the hole diameter in the stainless steel strainer inside the inside the Mipel Y Strainer ( Figure 085 ) and what is its equivalence in "Mesh"?

13- I have a swing check valve installed in line but it is not retaining the flow. What can be happening?

Answers:

1- When use a globe valve or a gate valve?

Gate valves are use to block or unblock the flow. This means that they must work totally opened or closed different from globe valves that can be used to regulate or block the flow.

2- What is the difference between a horizontal check valve and a swing check valve?

The difference is the class of pressure and the loss of charge. The horizontal check valves present bigger loss of charge compared with swing check valves.

3- What is the meaning of the words "PN" and "DN" stamped in body valve?

3) The stamps "PN" and "DN" are correlated to the pressure of work and size of valve respectively. See the following table:

4- How can I calculate the loss of charge in Mipel valves?

4) The loss of charge is given applying the formula:
hf = k . ( v² / 2g ) where:
hf = loss of charge ( in "MWC" )
k = coefficient of loss of charge ( informed by Mipel )
v = flow speed ( in meters / second )
g = gravity acceleration ( 9,81 m/s² )

5- What is the Standard for the Mipel Relief Valves ( Figures 037 and 038 )?

There is no standard. It is an own project by Mipel.

6- Mipel Relief Valves ( Figures 037 and 038 ) can be used as Safety Valves?

No. Relief Valves ARE NOT Safety Valves and CANNOT be used like this.

The difference between Relief Valve and Safety Valve:

Relief valves are recommended to be used in liquids, compressed air or even in some inert gases, when we need realize small pressure compensations in automatic and gradually way, with the valve opening or closing gradually as such as the pressure of the system increase or decrease, respectively.

Safety valves are recommended for use in steam and gases, when the necessity is to have a dispositive capable of relieving pressure in an instantaneous way. Generally Safety valves have a dispositive of effect "POP ACTION" ( instantaneous action of open and close ) that are nor present in Relief valves.

7- What is the set range for Mipel Relief valves?

From 10 PSI up to 150 PSI ( 1,1 up to 10 Kgf/cm² ).

8- How many "MCW" ( meter water column ) can a Mipel Relief Valve support?

Considering that 1 Bar = 10 MWC and that the Mipel Relief valve can be regulated until 10 Bar, it can support until 107 MWC.

9- What is the maximum temperature that a Mipel Relief Valve support?

The Mipel Relief valve supports the maximum temperature of 183° Celsius working regulated for its maximum pressure that is 10 Bar.

10- What is the class of pressure for the Mipel Ball Valves?

The ball valves do not follow the normal standard "PN/Pressure Class". To determinate what pressure they can support we must use the table "Pressure x Temperature".

11- How to use the table “pressure x temperature” for Mipel Ball Valves.

The use of the table is simple: there are in it two axes ( one representing pressure in PSI and the other representing temperature in °Celsius ). The proportion is reversed, what means that higher temperature of the flow lower will be the pressure supported by the valve.

I.E.: if pressure of the flow in the line is 400 PSI, the flow can have a temperature between 20°C up to 30°C ( see table ). In case of bronze valves the same table can be applied to all sizes.

Important: this table makes reference only to liquid flows and is not related for steam. The relation pressure x temperature of steam is different of the one showed in the table of Mipel Ball valves.

12- What is the hole diameter in the stainless steel strainer inside the inside the Mipel Y Strainer ( Figure 085 ) and what is its equivalence in “Mesh”?

In sizes ¼” up to 2” : stainless steel strainer with 95 holes by cm². Hole diameter: 0,5 mm ( Mesh 30 )

In sizes 2.1/2” and 3”: stainless steel strainer with 43 holes by cm². Hole diameter: 0,8 mm ( Mesh 20 )

13- I have a swing check valve installed in line but it is not retaining the flow. What can be happening?

Verify:

If disc is jammed;
If there is the presence of residues in the pipe line that can be jamming the disc;
If the inclination angle that valve is installed cannot be favorable for the closing action of the valve and favorable to open the disc.