Recent content by tsenthil

Recently i came across a requirement 16 Inch to 24 Inch ANSI 600 Class Ball Valves with Solid Tungsten Carbide trims. All the quotes i have received is with Tungsten Carbide Coating and not solid Tungsten carbide. The consultant is firm on his requirement (ie Solid Tungsten Carbide). 1. Is it...

Recently i came across a requirement 16 Inch to 24 Inch ANSI 600 Class Ball Valves with Solid Tungsten Carbide trims. All the quotes i have received is with Tungsten Carbide Coating and not solid Tungsten carbide. The consultant is firm on his requirement (ie Solid Tungsten Carbide). 1. Is it...

Dear Gerhard/Jim I came across the enclosed calculation for calculating Stroking speed for linear valves.. will we use this for Rotary valves?http://files.engineering.com/getfile.aspx?folder=87b6307e-c50c-443e-9b2a-eb12a64abe1c&file=SG_Stroking_Time.xls

Can anyone help how to determine the Solenoid/Air Filetr Regulator Cv required for attaining stroking speed in a Rotary Valve I have details like this Actuator Volumetic displacement - 165 litres Ball Valve closing time reqd - 15 Secs Ball Valve Opening time reqd - 15 Secs is there any...

I2I: Noise in Flashing duty.. Is there is anyway to find Noise produced in Flashing application? I normally made some correction in Vapor pressure to make the application cavitating and find the noise and presume noise produced in Flashing is less than Cavitating service. Most of the case i end...

HI Jim, Thanks for the post.. Can you explain how additional flow will happen in a choked condition by opening the valve? Thanks Senthil

Now i think that flow direction dont have any significance in flashing application. What we need is only a Hardened Trim to counter erosion due to Flashing. May be an Angle valve with Hardned trim will help in eliminating Erosion damage.

Even for Flashing, i believe the flow direction should be similar to cavitating service as inlet in only liquid. For Flashing we higher size valve or higher Cv required to handle gas expansion in the downstream.

A Piston Actuator can be used in a unbalanced trim to counter Bath Tub Stopper effect instead of standard Spring & Diaphragm actuators. However if your liquid is cavitating and valve manufacturer uses a muli Hole anti cavitation cage, the flow to be happen over the plug. They ideally want to...

You can use a positioner/Position transmitter combination to control the position of Pneumatic Actuator. Normally Positioner like Siemens PS2 or Fisher DVC2000 or Metso ND9000 are available with inbuilt position transmitter which will give you 4-20 mA output related to your Actuator position.

Jim, Its sounds very basic but please explain 1. Is Spool Valve and Flapper/Nozzle design(Fisher DVC) same? 2. Piezo valve is the same technique used in Solenoid Valves? 3. Some vendors (Siemens Sipart)claims their positioner as Fail Freeze. Is this related to Zero Bleed?

What is Non Bleeding Type Positioners? Can anybody explain in details. I thought all positioners has to bleed while in operation.

Can we use PTFE Gland packing in Fugitive Emission Control design (Globe Valves). I heard PTFE will fail during thermal cycle tests as prescribed in ISO 15848? Also is double packing arrangement is a must for FE design?

LF2 & LCB are basically same Low Temperature Carbon Steel, which can be used up to -49 deg C. LF2 means forging and LCB is the equivalent Cast Version. Normally Forging version limited to 4". Above 4" Casting is much cheaper. Whats the minimum design temperature? If it less than -29 deg C...

Yes Jim You are very much correct. In my previous post i limited to comparison of 2 types of actuators. Thanks for your valuable inputs.