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Do we need accumulators on compressors serving surge vessels. I assume without accumulators we will have a lot of banging around in the air line and it will be difficult to control the air injection ?

We have a project in the Middle East preparing design and specifications - the client has requested that the technical specifications are to be as published by CSI (construction Specification Institute. As far as we are aware the CSI provides a numbering system only - do the CSI publish...

If you are in soft deep peat them your pipe will eventually sink - laying the pipe on a raft made of geotextile/geogrid and bedding will spread the load without causing points of differential settlement. We would need to know more about just how soft the material is. I am not a lover of rocker...

Thanks again - I am sorry for not being clear - we are receiving the water from the desalination plants the RO and MSF supply are blended and then disinfected - the current disinfection is by chlorine. The client wants to change to Chlorine Dioxide. Water is stored in reservoirs providing 3 days...

Thanks for the reply - the project is in the gulf - 25% of the distillate is from MSF and the other 75% from RO. we are advised that the water can be received at up to 48 degree C - Why is it necessary to cool the desalinated water ? I assumed that only the "motive" water being drawn off the...

A flange MJ (mechanical joint) adaptor is flanged socket. It provides a flexible connection between the flange and the pipe - if you need to do any maintenance in the future you can dismantle the mechanical joint and open the flanged joint by pushing the socket onto the spigot. However some pipe...

Raising the water level in the chimney would appear to negate any purpose of the tank - the only effective storage you now have is the volume in the chimney !

In Peat i would advise with continuously welded pipe in peat not to build the pipe rigidly into the chamber all the thrusts on the valve will be taken by the welded steel pipe. Simply install the pipe through openings in the chamber and seal the annulus with flexible material to achieve a water...

The client wishes to change from CL to CLO2 to be manufactured on site from sodium Chlorite and HCL. water is desalinated water at 48 degree C volume is 50 Million gallons per day - dosing at 2 ppm, I am trying to prepare a budget estimate for the supporting infrastructure works. Question is...

We have a complex distribution system which is expected to experience a demand growth of some 50% over the next 10 years. The system has several sources of supply all from desalination plants which pump directly into the system through ground storage tanks. There are also a number of evaluated...

We have a design with 12 motors each 3.3 kV (power ratings from 300 Kw to 1000 Kw) 9 motors have VSD drives the other 3 have soft start. Incoming power supply is 11 kV. My question is why do we not transform the incoming supply to 3.3 kV instead of having one 3.3 kV transformer on each drive (12...

Thanks for the responses interesting consensus that with current computing capability we can evaluate the potential range of operation and evaluate were the system meets the pump duty range at extremes and we should be selecting a pump that best meets the potential operating range. I am now...

In the old days we often used to oversize water supply pumps - and then ended up adding orifice plates to bring them onto their duty curve - over the past 20 years I have instead evaluated worst case hydraulic scenarios (maximum and minimum) and ensured that the selected pumps best meet the duty...

Solution we have gone for is to standardize the drive size (we have a total of 4 pump groups each with two duty and one standby pump: each group as a different power rating) to that of the largest pump. We now have 12 VSD drives all the same. Some drives are therefore oversized. We will...

Thanks for the response = yes I could design a perfect system with 4 DOL duty pumps that would operate better , more efficiently and have a lower PV cost than what has been designed. But I have inherited the design too far down the road to change. What I do find is that the new breed of...

Thanks if we adopt DOL starting we would need to also install recirculation and control valves to protect the pipework. VFD will certainly protect/extend the life of all other components. Because of the criticality of the water distribution system the client is asking for standby VFDs for each...

I have inherited a water pump station design that has adopted two duty one stand-by pump sets. The pumps each rated at 1.8 MW are designed with VSD drive. The pumps are a sole source of supply to a distribution zone of a major city. The station must operate 24/7, Reliability is paramount for...

Thanks for the response. In this situation I would have adopted 4 duty and one stand-by and gone for fixed speed, however I have taken over a partially completed design with VSD and cannot go back. The client requirement for pumps and equipment is a minimum 25 year design life. My reading is...

VSD Reliability - We have 2 duty 1 stand-by pumps supplying direct into water supply distribution each pump rated at 1800 kW. We have proposed 3.3 kV - VSD drives. The system must have continuous operation and near 100% reliability. The client is concerned over the reliability of the VSD drives...

I have received results of hec-ras river modelling showing impacts of adding 1.0m high weirs designed to improve aeration in a river. I am surprised to find that the provision of a 1.0m high weir with a length equal to the full width of the river has created a 1.0m rise in water level. The...