Reciprocating Compressor Valve Failure: Diagnose, Repair, Prevent
If reciprocating compressor valve failure occurs, it’s always a good idea to learn how to diagnose, repair, and prevent this problem. Below is a helpful informative guide of what you need to know.
Reciprocating compressor valve failure can cause system lags and also affect the seamless operation of processes.
However, knowing how to diagnose, repair, and prevent compressor valve failure will ensure that the system reaches its natural life expectancy.
What’s more, a good working valve that performs according to plan will help in the even and effective distribution of compressed air for several processes.
That being the case, the need to ensure the long lifespan of the valve lies in the fact that it is one of the most significant parts that help in the regulation and flow of pressurized air.
What Causes Reciprocating Compressor Valve Failure?
The major culprits of reciprocating valve failure are environmental and mechanical factors.
Let’s take a closer look at each.
1. Environmental Factors
It is needful for a reciprocating compressor to be operated in a conducive environment where the machine is not constantly exposed to dirt and air-bound oil and mist.
A conducive workspace will not have elements and activities that could cause damage to the valves and other important components, which could further lead to performance issues.
Specifically, these environmental factors include:
- Improper lubrication: Stale or acidic lubricants can damage the metallic part of the valve.
- Corrosive contaminants: Corrosive elements that touch the valve can cause its metallic part to wear off.
- Foreign material: Foreign material in the reciprocating compressor can affect the valve’s inner lining and block airflow.
2. Mechanical Factors
Mechanical factors can also cause compressor valve failure, and these issues may develop internally in the compressor.
For instance, system overload or overheating can cause high levels of stress on the valve, thereby degrading this component.
Similarly, a compressor that is not used according to the manufacturer’s instruction may lead to a breakdown of the valve.
Some mechanical causes of compressor valve failure are:
- Spring failure: A wear down of the spring attached to the valve, due to stress could cause the improper functioning of the valve.
- High-cycle fatigue: The compressor’s operation at high cycles over a long time can lead to stress which could affect the valve.
- Off-design operation: Reciprocating compressors are of various models each suited to certain purposes. Hence, the use of a compressor beyond the operations which it was designed for could wear down the valve.
How to Diagnose Reciprocating Compressor Valve Failure
Here are some common signs that will help you to diagnose reciprocating valve failure, they include:
1. Overly High Suction Pressures
One of the signs of valve failure is high suction pressure which may be higher than the normal.
An obvious sign of poor system health is when surges in suction pressure are coupled with lower-than-normal discharge pressure.
Thus, these are two inter-related, valve-reliant functions that are performing contrary to system standards.
2. Low Discharge Pressure
Compressors discharge pressurized air at specific consistencies depending on the specification of the system settings.
However, a weak and inefficient discharge from a reciprocating compressor could be a sign of valve failure.
When the pressure appears inadequate, the valve passage may have been blocked.
In some cases, low discharge pressure is usually accompanied by excessive suction pressure.
3. Overly High Discharge Temperature
Low head pressure is evident when a discharge valve is unable to seal securely.
Here’s what it looks like:
At each upstroke, the air is discharged from the cylinder and this air can become pressurized within seconds.
Some of the air may eventually re-enter the cylinder through the unsecured valve seal.
Consequently, the subjection of air to this short cycle could cause more-than-normal high discharge temperatures.
4. Quiet Compressor
A compressor operating at low volumes may be something to applaud, but if the machine is working more quietly than usual, it becomes a thing of concern. The machine may be unable to operate at its full capacity.
Therefore, if your compressor has a fading sound or hums quietly, then there could be failing valves in the system.
How to Repair Reciprocating Compressor Valve Failure
Troubleshooting will enable you to repair reciprocating compressor valve failure. Try the following depending on the sign that is evident:
1. High Discharge Pressure
You need to inspect the unloading system to determine the cause of extremely high discharge pressure in your compressor.
The high discharge pressure can either be caused by a faulty unloading valve, instrument error, or extremely high demand on the system.
2. Low Discharge Pressure
Like the excessively high pressure, a compressor’s low pressure can be caused by a faulty unloading valve, instrument error, or leakage in the system.
Thus, you need to inspect the system for valve wear, leakage, or instrument problems.
3. High Discharge Temperature
When it comes to a high discharge temperature, you also need to ascertain the culprit by inspecting the LP valve and unloading system.
High discharge temperature can be linked to a faulty unloading valve, instrument error, or a worn LP valve.
4. Knocking Valves or Piston Rings Noise
Knocking noises emerging from the valves or piston rings could be due to insufficient head clearance, excessive cross-head clearance, or improper lubrication.
This issue can easily be tackled by inspecting the lubrication and adjusting the heads.
You need to ascertain if the lubrication was applied excessively or in insufficient quantities. Likewise, inspect to determine if the lubrication is old or acidic.
If either of these is the case, you need to wipe away the grease and apply the proper quantity of a new coat of a recommended grade.
How to Prevent Reciprocating Valve Failure
To prevent reciprocating valve failure in the near future, you need to do the following:
1. Examine Line Temperatures
You need to check the line temperatures on your latest chart if you suspect that your reciprocating compressor has a faulty valve.
Here, determine if the temperature is in line with the expected arc for the month or if there has been a sudden spike or dip in the chart since the first time you suspected a valve problem.
2. Check for Low Compressor Amp Draw
A reciprocating compressor can draw normal current levels while in operation or there could be infrequencies as a result of certain inability on the system.
Nonetheless, a low compressor amp draw will give the idea that there may be performance issues with your valve.
3. Check Compressor Shell for Overheating
Overheating can be attributed to bottled pressure in the compressor.
What happens here is the system’s inability to process air at a pace according to the program.
As such, heat may mount inside the compression chamber, thereby causing the shell to overheat.
Nonetheless, this issue can also be caused by a failed compressor valve.
4. Examine Valve Bypass When the Compressor Is Off
If the system is inactive yet the valve sounds like it is active, then it is a sign of valve failure.
The valve could make whooshing or whistling noise even after the compressor has been turned off due to stalling.
The failed valve is trying to complete processes that should’ve been done while the system was operating.
Reciprocating compressor valve failure is easy to diagnose, repair, and prevent if you’re informed on how best to go about each of these.
Once your valves are in order, their long life span will be assured instead of being tampered with by environmental and mechanical factors.
Hence, employ these tips to diagnose compressor valve problems, and fix them easily.
The best part is, you can prevent these problems from occurring in the future, and therefore, reduce the frequency of maintenance on your reciprocating compressor.
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