About Us

Our entire organization including production, inventory and Quality management systems are run by MRP software system. GMS Hydraulic aims to abolish all sources of wastage from entire steps of production. So production becomes faster, cheaper and better thanks to Six Sigma principles. Our products are tested under test machines which are equipped with electronic control systems. After quality and function tests are made successfully, goods are dispatched to our customers.

70% of our valves export to all continents of the World. Valves are produced by the highest casting techniques. Designs and production made by well equipped CNC machines and well trained CNC operators. Management policy of our company, aims continuous improve and innovation.

GMS Hydraulic closely follows developments in the industry, as a result of the importance given to quality management systems; GMS received ISO 9001 Quality Management System and EU Directive 97/23/EC CE mark.Our entire organization including production, inventory and Quality management systems are run by MRP software system. GMS Hydraulic aims to abolish all sources of wastage from entire steps of production. So production becomes faster, cheaper and better thanks to Six Sigma principles.

Our products are tested under test machines which are equipped with electronic control systems. After quality and function tests are made successfully, goods are dispatched to our customers. 70% of our valves export to all continents of the World. Valves are produced by the highest casting techniques.
Designs and production made by well equipped CNC machines and well trained CNC operators. Management policy of our company, aims continuous improve and innovation. GMS Hydraulic closely follows developments in the industry, as a result of the importance given to quality management systems; GMS received ISO 9001 Quality Management System and EU Directive 97/23/EC CE mark.


 

In hydraulic projects directional control valves are used in various. Almost in every project there is at least one directional control valve in the system.. Due to high volume of consumption there are many companies around the world who produces spool valves.  How you should choose the right spool valve and what should be specifications of the spool valve.   Typically hydraulic valves are made of cast iron. Sand cores are used inside the cast iron hydraulic valve to create cavity for internal rooms and oil drain.

In this phase casting and sand core production technology is the most important point. If the sand core is not in high quality the cavity which needs to be created will not be created so directional control valve will not work properly. On the other hand there can be other problems due to cast iron. These types of casting problems are mainly seen on Far Eastern oriented directional control valves.

One of the other main points which have big effect on quality of directional control valve is internal cleanliness of the valve body. After casting process the directional control valve body should be cleaned with special treatments against slag dirt and sand core dirt. Remnants inside the hydraulic valve is not only because of casting but also is because of chips after machining. These remnants have huge effect on performance of spool valves.  Contamination level  of  directional control valve which works under pressure lower than 140 bar  is 20/18/15 and filtration level is 20 micron, however contamination level  of  directional control valve which works under pressure higher than 200 bar is  18/16/13 and filtration level is 5 micron. If contamination and filtration standards are not applied, dirt damages all system components and spool valve.  Professional companies use special techniques for cleaning valves. On the other hand, test bench monitoring system checks and calculate contamination level of the oil. So testing procedure does not increase contamination level of the monoblock valve.

Designing spool for monoblock valves needs experience and special calculations. Dimension of the spool, grooves, notches and overlaps has huge effect on characteristic of the monoblock valve.  For instance in excavator application smooth opening and proportional movement is very important so characteristic of the spool is the main factor in this application.  Not only design but also quality of the spool is important. To catch high quality level spool material and grinding is important. Internal leakage of the monoblock valve gives idea about grinding and honing quality.  Internal leakage level of the monoblock valves are given by manufacturers. For instance internal leakage of GMS brand monoblock valve is 2-3cm3/min at 100 bars. When the internal leakage increases monoblock valve loses load holding function.  In a field test it is tested with a loaded front loader. If the internal leakage of the monoblock valve is high the bucket of the front loader will fall early when compared to a monoblock valve which has lower internal leakage.

Another undesirable circumstance in hydraulic systems is heat. Generally heat occurs because of friction and kinetic energy turns into heat energy.  Meanwhile pressure drop occurs and pressure drop is the reason of energy loses in monoblock valves. To prevent energy lose high permeability monoblock valves should be chosen for hydraulic systems.  A monoblock valve which has 45 liter permeability can go up to 70 liter however there will be high pressure lose and overheating.  Important point is not the permeability of the monoblock valve important point is permeability in which pressure how many liter.